26 de octubre de 2023

A review of the literature on sclerotia in Leucocoprinus species and other Agaricales


Whilst there are many fungi known to produce sclerotia, documentation of them in Leucocoprinus species is lacking with only a few species recorded as producing them and little information on each. As L. birnbaumii is one of the most common species to find in plant pots and has sclerotia which are readily visible owing to their size, colouration and vast numbers spreading across the top of the soil this may be suggestive of sclerotia facilitating transmission via potting soil. It seems probable that other Leucocoprinus species found in plant pots can also spread via sclerotia, but that they simply produce less visible sclerotia which go unreported. Culturing Leucocoprinus cretaceus in a sterile substrate has produced abundant sclerotia followed by mushrooms and sclerotia have also been found in cultures of L. cepistipes and L. cepistipes cf. var. rorulentus both from plant pots. This review was initially intended to research which Leucocoprinus species sclerotia had previously been documented in. However besides from Mattirolo's 1918 study there appears to be little documentation of sclerotia in Leucocoprinus species. Sclerotia are not documented in many Agaricales in general but studies of sclerotia in some Coprinopsis species reveal some universal traits that are applicable to other species. Minute sclerotia have subsequently been found stuck to the stipe of Conocybe cf. macrospora from a plant pot demonstrating how easily these structures could be overlooked if not specifically looking for them. This literature review is therefore presented in order to summarise information such that it may assist in future research into sclerotia.

1. Introduction

The presence of sclerotia in Leucocoprinus species appears to be an under-studied subject with little to no documentation of sclerotia in anything other than Leucocoprinus birnbaumii and only a small number of Agaricales documented as producing sclerotia.[1] The large number of observations of L. birnbaumii provides good evidence for how abundantly sclerotia are produced by this species as they are readily seen but it may not be so apparent with other species as they do not get documented and are not easily seen in observation photos. The yellow to whitish-beige sclerotia of L. birnbaumii are frequently visible on the top of soil in plant pots, in bags of compost or against the glass of terrariums and vivariums growing amongst the coir. At a little under 1mm in size (500-800µm),[2] these small, hard structures are easily seen with the naked eye and indeed frequently become noticed.

As these sclerotia are produced in such vast numbers and are of such a discreet size they could be easily distributed through potting soil when plants are repotted or propagated from root suckers. This may provide an explanation for how this species was introduced into greenhouses and plant pots from tropical plants brought back by early explorers and why it continues to be a common find in plant pots. Such structures could function similarly to resting spores allowing the species to lay dormant in soil until conditions are right to grow.

Houseplant blogs and forums are a good source for observations of these sclerotia because when people find them in their pots they tend not to know what they are looking at and so automatically worry that it may harm their plants and hence are inclined to seek advice online. Posts asking if they are mold, spider mite or insect eggs are common - as are people responding and diagnosing it as one of these things. The fear of the unknown is such that people will often panic and replace all their soil or dowse it in vinegar, hydrogen peroxide or even odder home remedies which seem unlikely to work and more likely to harm the plant than taking no action would.

Search engine image results are therefore full of observations of Leucocoprinus sclerotia misdiagnosed as something else entirely. Many people do however recognise them as a common fungus that is harmless for the plant and so reassurance usually comes, occasionally with an identification of them as L. birnbaumii but very rarely with the explanation that they are sclerotia. When they do get identified as L. birnbaumii, they're usually either dismissed as primordia, mycelium or no further description is provided. Despite sclerotia in L. birnbaumii being documented a long time ago and being commonly observed ever since it appears that information about them just has not been widely disseminated. Given the lack of awareness and scarcity of information on the sclerotia which are so readily visible in L. birnbaumii it is perhaps no surprise that there appears to be little information on sclerotia in other Leucocoprinus species. It may be that it is only via culturing these species that their sclerotia production can properly be documented and explored.

Observation 68805306 - Leucocoprinus birnbaumii sclerotia Credit: @zorille Observation 175638202- Leucocoprinus cretaceus sclerotia in culture Credit: @mycomutant Observation 134794364- Leucocoprinus sp. sclerotia Credit: @pogona_vitticeps

2. Taxonomic history of Leucocoprinus sclerotia and previous studies

Sclerotia of Leucocoprinus species appear to have been observed and described many times since the 1800s with some early classifications of them as fungi imperfecti belonging to an unknown species before observations of them were made with the associated mushrooms. The taxonomy on them however is confusing and filled with many erroneous entries and mistaken information, much of which is addressed by Oreste Mattirolo in his incredibly comprehensive 1918 text (in Italian).[3] This work appears to the be the most comprehensive study of Leucocoprinus sclerotia to date with much of the taxonomy addressed by Mattirolo and so the key points will be summarised here along with collating the other sources.

Paul Christoph Hennings may have been the first to describe the sclerotia in a Leucocoprinus species along with the associated mushrooms in 1898 when they were noted growing on soil in the hothouses of Heinrich Hildmann's cacti gardens in Birkenwerder, Germany. The early taxonomy of Leucocoprinus species however is just as confusing and conflated as that of the sclerotia and so Hennings attributed them to L. cepistipes, though described the mushrooms as golden yellow suggesting he was actually describing L. birnbaumii. This confusion is common owing to a number of early illustrations and descriptions which conflated several species or considered them all the same, only varying in colour. The sclerotia are described as small, barely 1mm in size, light yellow and felt-like which does match the appearance of sclerotia in L. birnbaumii. Hennings compares them to Sclerotium mycetospora Nees ex Fr.[4]

2.1. Sclerotium mycetospora and S. sinapispermum

Nees covered Sclerotium species extensively in his own work[5] but the description of Sclerotium mycetospora comes via Fries in 1822. They are said to be like mustard seeds in habit, gregarious, starting pubescent and white. He notes they favour the light, grow amongst the bark in hothouses and grow into Agaricus volvaceus and so they are compared with Sclerotium pubescens which he says also grow into Agarics:[6]

S.? mycetospora, liberum, subtectum, globosum, lævo, stramineo-album, basi tenui byssinae insidens.
S. mycetospora. Fr. Nees in litt.
Habitus seminis Sinap. albæ, gregarium; primo obsolete pubescens, album; mox glabriusculum, stramineum. Observante Cel. inventore astate, favente luce! (h. e. non obtectum in Agaricum volvaceum excrescit. Inter corticem in Caldariis. (v. s.)
Cum status modo elementaris & e vegetatione, luce priva, personatus sit, strictissime omittendus; tamen ad indolem reliquorum, quibus simillimum, illustrandam maxime confert, quare inserere non dubitavi, Cf. Scl. pubescens, fungorum etc, quæ etiam Agaricos progignunt.

In 1863 Gérard Daniel Westendorp described Sclerotium sinapispermum as growing from tan bark in a hothouse in Menen, Belgium. They were noted as being spherical, smooth, 0.5-1mm in diameter and starting yellowish before maturing to orange and then red-brown with a distressed surface when dry and free from the mycelium:[7]

Scler. sinapispermum n. sp.
Péridium sphérique, d'un demi à un mill. de diamètre; à l'état frais d'abord jaunâtre puis orangé, lisse et adhérent par un point; à l'état sec libre, d'un rouge brun et légèrement chagriné à la surface. Chair cornée blanche.
Sur la tannée, dans une serre chaude à Menin, chez l'horticulteur Vander Plancken.

This description seems to strongly align with that of Leucocoprinus sclerotia in regards to the dimensions, colour and habitat. The note of them adhering to a point is also of great relevance as this trait becomes very apparent and at times quite frustrating when trying to study the sclerotia in various Leucocoprinus species. They will readily stick to a needle tip, scalpel or any instrument used to manipulate them. As such attempts to locate them on a slide or dissect them can prove frustrating although in practice it does mean that isolated sclerotium or small clusters can be purposefully collected for study simply with the tip of a needle.

In 1867 Jean Kickx suggested that S. sinapispermum was synonymous with S. mycetospora.[8] In 1889 Victor Fayod noted that Sclerotium mycetospora belonged to Volvaria volvacea (now considered a synonym of Volvariella volvacea).[9] This association however seems to only be based on the previous one with Agaricus volvaceus and Fayod does not provide any more information. Sclerotia were also noted by Adalbert Ricken in 1915 who cited Hennings description and attributed them to Lepiota cepaestipes, describing the cap of the mushroom as whitish, yellowish or even sulphur yellow.[10]

In 1918 Sclerotium mycetospora was categorised by Mattirolo as having white sclerotia and classified as Lepiota incerta.[3] In 1948 Karel Cejp reclassified this as Leucocoprinus flos-sulphuris var. incerta.[11]

The association with Volvariella volvacea makes the identity of the species Fries was describing unclear and the mention of Sclerotium pubescens also growing into an Agaric species is confusing. Christiaan Hendrik Persoon described Sclerotium pubescens in 1801 as gregarious, globose and pale with a hairy base and said they were found in Autumn on the gills of a decaying Agaric mushroom, the type of which is not further specified. This does not sound like a species which grows into an Agaric mushroom but rather a fungus that decomposes them. Little other detail is provided besides them being 1 line wide.[12] This would correspond to ~2mm or ~2.25mm so seems too large for the sclerotia of a Leucocoprinus species unless it is greatly rounded up. Collybia tuberosa and similar species grow on decomposing mushrooms and produce sclerotia which are around this size or larger so may provide an explanation.

Additional sources of confusion for Leucocoprinus sclerotia may be some Aspergillus and other mold species growing on decomposing mushrooms. It is not uncommon to see observations in which sclerotia of L. birnbaumii are found alongside Aspergillus or other molds which are either decomposing the mushrooms or consuming material in the plant pot. If both were found together it could easily cause confusion with the assumption that they were related due to their similar appearance. The sclerotia and associated mycelium do have an appearance similar to many molds.

Observation 142511321- Aspergillus growing on a mushroom Credit: @pipsissewa Observation 142511321- Aspergillus close up Credit: @pipsissewa
Observation 150294254- Hypomyces species on polypore Credit: @komille277 Observation 3922092- Moldy Leucocoprinus Credit: @williamgarner

2.2. Sclerotium hirsuta and Periola hirsuta

Periola hirsuta was Elias Magnus Fries' 1822 reclassification[13] of Sclerotium hirsuta as described by Heinrich Christian Friedrich Schumacher in 1803.[14] As Mattirolo points out however there are numerous issues with the reclassification and description as Periola. This description is provided by Fries:[13]

P. hirsuta, obconica, hirsuta, ochroleuca.
Scl. hirsutum. Sehum. Saell. 2. p. 187. Fl.Dan. t.1320,
Sparsa, simplex, superficialis, 2 lin. fere longa, subturbinata, intus pallida, versus basin umbrina. Substantia carnoso-gelatinosa. Ad Rhizomorpham subcorticalem supra truncos vetustos fagineos. Sept. (v. ic.)

The habit described here misses some critical features of the original description and seems to suggest growth on old Beech trunks. Fries also cites Florae Danicae Iconum tab 1320 (MCCCXX).[15] This illustration appears to be something unrelated. Based on the illustration and the description provided by Fries it would seem doubtful that this is a description of Leucocoprinus sclerotia at all. However the original description by Schumacher[14] provides more detail:

S. hirsutum, obconicum subturbinatum, hirsutum, ochroleucum, intus pallidum basin versus umbrinum; substantia carnoso-gelatinosa.
In vasis exsiccatis subcorneis trunci cæfi Fagi sylvaticæ. Septembr.

It specifically notes that they were growing in vessels containing the dried Beech bark - a common habitat in which to find Leucocoprinus species with many of the early descriptions being from bark beds in hothouses. Given this context the more appropriate translation of vasis may be vases or plant pots but no further information is provided.

Mattirolo addresses these issues and states that the illustration represents greatly enlarged structures and that it did not correspond to the truth, the specimens having been communicated to the artist by Schumacher rather than observed and drawn by the same person. He notes that the size given by Fries of 2 lines long corresponds to 4.5mm, stating that this is about five times larger than the actual size and that Fries arrived upon this size by measuring the fungi depicted in the illustration rather than observing specimens personally.

Mattirolo notes the importance of the colour description given and provides a definition[3] (translated from Italian via Google):

Ochroleucus, means exactly one color, albo-flavidus, corresponding to that of candle wax; but not to that of beeswax. This name derives from ochros == yellow earth, and leucos == white. Since it is important for our study to fix exactly the value of the Chromotaxia colors of P. A. Saccardo. Editio alter. Patavii, 1894.

Kew's website notes that confusion can arise over colour citations given in Chromotaxia due to the alteration of the colours in the book with age.[16] So this definition, which is just buried amongst the references in the footnotes on the page is more useful than it may appear as the surface of the sclerotia can indeed appear wax like with some variation in colour between species.

Mattirolo goes on to cover, in great detail the string of errors surrounding P. hirsuta that resulted in another seemingly erroneous illustration being created by August Karl Joseph Corda in 1837-38 in Icones Fungorum. A citation of volume II, tab XIII, fig. 160 is given however this appears to be a transposition error as the illustration is actually figure 106.[17]

Corda describes the entire outer surface as being covered in flakes and polygonal spores arranged one after the other like beads on a thread and says that these spores were able to germinate and produce new fruiting structures.[17] In 1910 Teodoro Ferraris also illustrated and described P. hirsuta with conidia and stated that it was affiliated with Volutella.[18]

Mattirolo concludes, based on his own contamination prone attempts at cultivation of the sclerotia, that the spore bearing conidia described by these authors as being present on the surface of P. hirsuta are either the result of mold such as Penicillium growing on the sclerotia or the internal tissue of the sclerotia spilling out when crushed. Based on my own observations however I would posit another theory - that these authors may not have even been observing the sclerotia.

Fig. 1 - Chaetomium contaminant found in L. cretaceus culture. Fig. 2 - Corda's illustrations including Periola hirsuta Fig. 3 - L. cretaceus sclerotia from agar erupting with crystals.

The Chaetomium species (fig. 1) that has contaminated many of my own attempts to culture Leucocoprinus species would appear to resemble Corda's illustration of Periola hirsuta (bottom left corner of fig. 2). In some cultures this was observed to be growing side by side with the sclerotia and the immature forms of them were initially indistinguishable to the naked eye, appearing only as tiny white specks scattered gregariously across the substrate. As the Chaetomium developed further it became greenish yellow and ultimately dominated in most of these cultures eventually colonising the entire jar and appearing like a greenish black or grey mold throughout. This appearance is not wholly dissimilar to a jar colonised by L. cretaceus in which the vast number of mature, black sclerotia amongst the white mycelium results in an overall grey, mold like look.

In others where Leucocoprinus sclerotia were noted and aborted primordia were present, spores resembling those of Chaetomium were also found amongst the crushed sclerotia when examined under the microscope. This initially caused confusion in identifying the sclerotia as whilst the number of spores was comparatively few it could appear as if they were spilling out of the crushed sclerotia. Chaetomium spores are somewhat similar in appearance to those of L. cretaceus so it was not clear if the spores were left over from inoculation or if they belonged to the Chaetomium species. Attempts to culture these sclerotia however instead produced jars filled with Chaetomium. They are immediately distinguishable from sclerotia when examined microscopically due to the vast numbers of spores that spill across the slide when crushed - a feat that was easy with the Chaetomium, which offered little resistance compared to the sclerotia that took force to crush.

Additional confusion was caused by the crystals that spilled out of some crushed sclerotia that were cultured on agar (fig. 3), at low levels of magnification these looked as if they could have been spores and were quite polygonal in form, as many crystals are. At higher levels of magnification it became abundantly clear that they were crystals and they were also noted in agar around the tips of the hyphae that were forming into sclerotia. This potentially suggests that this aggregation of crystals represented the crystals collected from many hyphae as a store of nutrients in the centre of the sclerotia however whether this phenomenon is just the product of growing in an agar mix with a high sugar content has not been evaluated yet. Distilled water was not used for this agar mix and the water has a high mineral content so Calcium oxalate crystals are also a possibility. Some crystals appeared colourless whilst others had a brownish yellow colour, similar to that of the malt extract agar itself so there may have been multiple different crystalline structures present. Some crystals have also been noted in the sclerotia of L. cretaceus and L. cepistipes cultured on water agar but such crystalline structures have so far not been observed in sclerotia collected from other substrates so may simply be from the agar.

With or without crystals, the sclerotia and the Chaetomium could reasonably be conflated and confused and it may be that they are only easily distinguished with a modern microscope and camera to compare images. This common soil fungus which appears somewhat similar to the sclerotia of Leucocoprinus species may explain the confusion in this illustration and Corda's description. When the outer casing of the sclerotia turn black with age they appear quite similar to the black centre of the Chaetomium fruiting bodies and the yellowish green hairs on them could appear like some other mold. Additionally, as neither Corda or Ferraris remark on the hardness of the structures or note any difficulty in crushing them beneath a cover slip it does not seem likely that they were actually examining Leucocoprinus sclerotia. The hardness is such that mounting them for examination is not trivial and so it seems like it would be impossible not to make note of this trait.

Interestingly it was Corda who gave L. birnbaumii the specific epithet that it has today in the third volume of Icones Fungorum, it famously being named for a Mr Birnbaum, a gardener in Prague who found the species growing amongst pineapples in hothouses in the Salmovský gardens. Yet in his description of L. birnbaumii Corda does not note sclerotia.[19]

Other mycologists of the time seem to provide vastly different descriptions of P. hirsuta that more closely fit those of the sclerotia of a Leucocoprinus species. In 1899 Domenico Saccardo provided a description of P. hirsuta from sphagnum moss in plant pots in a greenhouse in the Treves garden in Padua, Italy:[20]

Sporodochi superficiali, rotondi, internamente duretti o carnoso-gelatinosi. Conidi globoso-ovoidei, tipicamente disposti a catenella, fra le setole, continui, ialini.

— Sporodochi sparsi, quasi rotondi, un po' pelosetti, 0,5-0,7 mm. diam., esternamente bianchi ed all'interno duretti e di color nocciuola pallido; ife del contesto irregolarissime, intrecciate, ramose, 6-10 μ. di grossezza, le periferiche ialine, filiformi, un po' ramose, grosse 3 μ., spesso granulose. Conidi globoso-cubici, ialini. Sulle foglie degli Sphagni sparsi sui vasi, in una serra del giardino Treves a Padova.

Whilst this description still mentions conidia the description otherwise sounds like a good match for the sclerotia of a Leucocoprinus species. The size of 0.5-0.7mm, almost round and hairy structure and the external white colour with a pale hazelnut colour internally are consistent if examining sclerotia that are still encased in their mycelial envelope. As is the description of them as hard or fleshy and gelatinous since this can change with maturity. Dried material from this collection is stored in a herbarium so could be further evaluated.

Mattirolo states that he communicated details on this species in 1900 to P. A. Saccardo having made a collection from the sphagnum moss used as a substrate in orchid greenhouses in Florence and Turin. This was followed by a further collection by D. Saccardo in 1904 from orchid greenhouses in Rome where it was described as growing easily even on the bare backs of vases and not being harmful to the orchids or other moss covered plants. This is describing a typical trait of L. birnbaumii sclerotia which is commonly seen in observations on iNaturalist and houseplant forums. They have a tendency to grow on the underside and around the base of terracotta pots and in the drip trays, often in vast numbers. The association with orchids has also been frequently noted with professionals in the modern Orchid industry regarding them as problematic due to their appearance reducing the decorative value of the plants.[21]

In 1918 Sclerotium hirsuta was categorised by Mattirolo as being the species with the ochroleucus sclerotia and was classified as Lepiota flos sulphuris,[3] a reclassification of Schnizlein's Agaricus flos sulphuris.[22] In 1948 Karel Cejp reclassified it as Leucocoprinus flos-sulphuris.[11]

Observation 20014723 - L. birnbaumii sclerotia in sphagnum moss Credit: @captaxon Observation 35644569 - Leucocoprinus sclerotia in drip tray Credit: @carlesbeebe Observation 18189317 - Leucocoprinus sclerotia Credit: @mira_l_b Observation 160794482 - Leucocoprinus sclerotia in drip tray Credit: @bmack

2.3. Lepiota flos-sulphuris and Lepiota lutea (Mattir.)

In 1851 Adalbert Schnizlein described Agaricus flos sulphuris growing from moss used to top the beds in a hot house in the botanical garden. He says it often appeared after the moss had been in use for one and a half years and whilst he does not explicitly describe sclerotia, he does note that the mushrooms arise in many places simultaneously in great numbers in masses agglomerated by mold, which he described as a very pretty sight. This is accompanied by an illustration of Agaricus (Lepiota) cepaestipes Sowerby, but it is completely yellow, again suggesting that it was L. birnbaumii which was observed.[22] Schnizlein cites Ludwig Rabenhorst's description of Agaricus cepaestipes that is similar to his observation but white[23] and so the name Agaricus flos sulphuris meaning flower of sulphur was used instead because of the yellow colouration.[22]

Mattirolo acknowledged that William Withering's Agaricus luteus, Corda's 'strangely named' Agaricus birnbaumii and others may have been analogous to the yellow species he was observing however he settled upon Lepiota flos-sulphuris to distinguish it from Lepiota lutea which he also described. Lepiota flos-sulphuris was described as scaly, flocculose and bright sulphur yellow with concolourous gills and orange flecks in the centre of the cap. A spore size of 8-10 x 4-6 μm is given. Mattirolo only noted this species growing in greenhouses with tropical plants so concluded it was a species of tropical origin that was introduced to Europe with these plants, though noted it could spread to others and was not dependent on them.[3]

Mattirolo observed ochroleucus sclerotia associated with this species which had a creamy coloured mycelial envelope that was 10 µm thick on average whilst the overall sclerotia reached just 1mm diameter on average. The mycelial envelope hardly disappeared when rolled between the fingers and a repeated force was required to remove it, resulting in yellowish brown colouration showing through and the sclerotia becoming smaller. When fresh they resist crushing and 'escape the razor cut' and when dried they have the hardness of grains of sand. They retain their colour in alcohol with the mycelial coating not changing in character or colour. The sclerotia grow very close to each other with a yellowish bysoid mycelium holding them together.[3]

Lepiota lutea was described as very close in its general appearance but with the sulphurous yellow colour of the mushroom being lighter and lacking the orange colouration. It has a slightly swollen but not bulbous stipe which is scaly or hairy but lacks the flocculose coating. More importantly the spore size is far smaller at 4-5 x 3-4 μm and so it is clearly distinct. Mattirolo noted this species as growing on terra di castagno and on old trunks of various species. It was not exclusive to the greenhouse environment with it being found outside in the regions of Piedmont and Lombardy, Italy always on terra di castagno. From this he concluded that this species was not of tropical origin and was native to Europe. Sclerotia were not observed in this species.[3]

Terra di castagno is a substrate of decomposing chestnut wood which literally translates as 'chestnut earth' or 'chestnut soil', though does not yield results in English for these search terms. Italian results describe it as very acidic, nutritious and excellent for almost all plants.

Recent ITS sequences posted to iNaturalist with accompanying photos do suggest multiple species going under the name of L. birnbaumii and genbank results are fairly inconsistent with many sequences submitted under this name that are only 90-95% matches with others. It appears that there are in fact a number of similar yellow Leucocoprinus species found in plant pots which routinely get confused. Observation 135980665 by @sarahmycena and 26909898 by @pycnoporus with sequences provided by @stevilkinevil appear to show paler specimens than is seen with 126103447 by @kev317. The sequences for these are distinct as is observation 19645434 by @alan_rockefeller from a pile of wood chips in California which likewise differs genetically and appears to have a slightly different colouration. Appearances can vary however due to rain or watering washing out the yellow pigment in some specimens resulting in a pale looking cap with brighter yellow centre and so distinguishing specimens via macroscopic characteristics is complicated by environmental conditions.

Observation 57857449- Immature mushroom Credit: @roalvagcoral Observation 57857449- Washed out mushrooms Credit: @roalvagcoral Observation 107519035- Immature mushrooms Credit: @kwhelan Observation 107519035- Washed out mushrooms Credit: @kwhelan

This does not appear to be the case with Mattirolo's Lepiota lutea however as it has a spore size more consistent with that of Leucocoprinus straminellus or L. medioflavus. The photos Mattirolo includes are in black and white but do look similar to the few confirmed photos that are available online or in papers for these species and his illustration (fig. 4) also confers with them, showing pale mushrooms with a brighter yellow centre. By contrast Mattirolo's illustration of Lepiota flos-sulphuris (fig. 5) looks like L. birnbaumii.

Differentiating Leucocoprinus straminellus, L. flavescens and L. medioflavus in photos is as yet unclear to me especially given the virtually identical white variants Leucocoprinus straminellus var. albus and L. medioflavus var. niveus.[24] Observations for these species are not as common as for L. birnbaumii but are by no means rare either so in time it should be possible to acquire enough samples to try and distinguish them. For the time being I have just been collecting observations of them here in order to better compare them. Many of these observations appear to match what Mattirolo was observing with Lepiota lutea. I have so far only examined the spores of one such specimen with a similar macroscopic appearance and a small spore size that fell within this range. Attempts to culture it however resulted in very slow growth that ultimately succumbed to contamination with efforts to save it proving futile vs the contaminants that grew far quicker. A culture was left to grow on wheat bran for some months however and in this period no sclerotia were observed though further study would be needed.

iNaturalist observation 134794364 by @pogona_vitticeps seems to show a pale species with a brighter yellow centre developing abundant sclerotia in a bag of potting soil however the mushrooms are under developed or possibly deformed and so it is not clear what they are. A similar appearance is found in observation 173147298 and 174912287 by @jarenjaren and this one has recently been sequenced with the results showing only a 92-93% match with L. birnbaumii and a 96% match with L. straminellus. So L. medioflavus might be the correct identity for this observation but microscopy will be required to confirm. Observation 183108232 by @hikasukepon also appears similar and has microscopy which also suggests L. medioflavus as a probable ID.

Fig. 4 - Lepiota lutea Fig. 5 - Lepiota flos-sulphuris Fig. 6- Lepiota incerta with sclerotia

2.4. Lepiota incerta

Mattirolo described Lepiota incerta as a new species so no synonyms are listed. The cap and gills are described as straw-white (stramineo-albo) with a stem that is flocculose with a bulbous white base and Isabelline (pale cream brown) around the annulus. The spore size is given as 8-10 x 4-6 μm, the same as for Lepiota flos-sulphuris but also similar to many species of Leucocoprinus that have been described by others. He describes minute scales in the centre of the cap but when he says 'ad centrum tantum carnosulo' 'only fleshy in the centre' it is unclear if this is in reference to the thickness of the flesh or a fleshy colour, since his illustration (fig. 6) does show a brownish or creamy brown colour around the centre that is not otherwise noted in the description.[3]

With this species, Mattirolo observed white sclerotia with a diameter greater than 1mm with a tomentose, milky white mycelial envelope that was 3-4 µm thick. It disappeared easily when handled between the fingers resulting in the sclerotia becoming much smaller and a hazelnut colour showing through. They had a more gelatinous consistency making them more easily crushed and dissected and when dried they were not as hard as the ochroleucus ones. In alcohol they immediately lost the white colour with the mycelial envelope becoming transparent and a distinct brown colour showing through. The sclerotia grew spaced apart and linked together by white mycelial cords but lacked the bysoid mycelium.[3]

Mattirolo compared the mushrooms with Lepiota cristata, Lepiota tenella (=Leucocoprinus tenellus), Lepiota serena (=Leucoagaricus serenus), Lepiota morieri (=Cystolepiota seminuda) and Lepiota brebissoni (=Leucocoprinus brebissonii). The greatest affinity was noted as being with Agaricus (Lepiota) straminellus (=Leucocoprinus straminellus), the dried specimens of which are said to be so similar as to appear identical.[3]

It is unclear to me which species Mattirolo was observing but based on the illustration I believe the best contender could be Leucocoprinus ianthinus given that it is also commonly observed in plant pots. However based on some differences apparent in the macroscopic features and different microscopic features noted by many authors it seems likely that there may be two similar species so some of these observations could be L. lilacinogranulosus. As this species is currently considered a synonym by Species Fungorum and Mycobank observations of L. ianthinus may represent a collection of both species.

iNaturalist observations would suggest that Leucocoprinus brebissonii is commonly found in the wild worldwide with many observations especially on the West coast of the United States but it does not seem to be a common find in plant pots. A review of the over 700 observations of this species on iNaturalist (research grade, casual and 'needs ID') has not turned up any definite observations of this species in plant pots.

By contrast the over 300 observations of L. ianthinus on iNaturalist suggest they are almost exclusively found in plant pots. There are some observations from the wild in Florida, Georgia, Alabama and Louisiana which commonly get suggested as L. ianthinus by the iNaturalist algorithm and indeed do look quite similar, though it is currently unclear which species they are. There are also similar observations from Australia, though these generally have some slight differences in appearance to the American ones and it is possible that L. austrofragilis may match some of the Australian ones.

It is not clear where L. ianthinus is actually native to or how it became introduced into Europe and the rest of the world. Exploring the taxonomy on some of the common houseplants of tropical origin like Pothos (Epipremnum aureum), Montserra and Dieffenbachia with which these mushrooms are commonly found could suggest possible origins, especially in cases where the plants were introduced to hothouses in Europe shortly before the mushrooms were described (Pothos and Agaricus ianthinus were both described in the 1880s). However as the description of L. ianthinus does not give any information on the nearby plants in the hothouse at Kew in which it was found and the text on Pothos does not explicitly mention when or if specimens were sent to Kew this is at most speculative and inconclusive.

Flora Agaricina Neerlandica gives a spore size for Leucocoprinus brebissonii of 8.5-13 x 5-8 μm or 9.3-11.5 x 5.6-7 μm on average and for L. ianthinus it notes 8-12 x 5.5-7.5 μm or 9.4-10.4 x 6.5-6.7 μm on average.[25] Mattirolo's Lepiota incerta is close at 8-10 x 4-6 μm but would not seem to be a strong match to the range given here. Derek A. Reid gives a smaller spore size for L. ianthinus of 6.5-10 x 5.75-6.5 μm in contrast to a size for L. lilacinogranulosus of 7.5-9.75 x 5-7 μm or 6-7 x 4.75-6 μm. L. lilacinogranulosus var. subglobisporus is noted as having globose or subglobose spores at 4.5-6 x 4.2-5 μm.[26] Jean Louis Émile Boudier produced illustrations of Leucocoprinus tenellus which appear similar to Mattirolo's illustration of Lepiota incerta[27] however a spore size of 12-14 x 7-8 μm is given.[28] Mattirolo noted this species as being related but differing in colour, type of annulus and spore size.

Other similar looking species have been described such as Leucocoprinus otsuensis from Japan in 1953 by Tsuguo Hongo which was said to be closely related to L. brebissonii but being easily distinguished by the scales on the cap, which are dark brown. The spore size given is 9-11 x 6.5-7.5 μm or 10-13 x 6-8 μm.[29] Species Fungorum lists the current name as Lepiota otsuensis Hongo whilst Mycobank has it as a synonym of L. brebissonii.

The uncertainty of which species Mattirolo was dealing with is reflected in the name incerta which is Latin for uncertain, a name which Mattirolo said he gave the species as it signified his thoughts. It is easy to see why Karel Cejp considered this species to be a variant of Leucocoprinus flos-sulphuris given the identical spore size, the presence of similar sclerotia and Mattirolo's uncertainty as to its identity.

It could even be tempting, were Mattirolo's work less detailed and thorough, to dismiss them as just the same species. The illustration of Lepiota incerta has a colouration quite similar to that of many Leucocoprinus species when they are old or dried where the yellow colours become more grey brown or beige. The larger, white sclerotia that are gelatinous and less hard could represent a more immature form which appears larger before the softer tissue hardens and loses water content. Collecting hundreds of observations of Leucocoprinus sclerotia in an iNaturalist project has made it possible to easily compare them and look for differences and similarities. Colours appear quite variable from a distinctly yellow to white or more of a beige colour but bright yellow mushrooms that appear to be L. birnbaumii are present in enough of these observations to suggest that these sclerotia belong to the same species regardless of colour, hence distinguishing the sclerotia by colour may not be reliable. Sclerotia in L. cretaceus and L. cepistipes also appear white when immature and it seems likely that if other Leucocoprinus species produce sclerotia they will be similarly white like the mycelium.

Additionally the yellow pigment present in the sclerotia or mycelium of L. birnbaumii leaches out and diffuses into a solution of 10% Potassium hydroxide (fig. 7). This may be Birnbaumin A or B, the same 1-Hydroxyindole pigments that have been isolated from the fruiting bodies via methanol extraction.[30] Considering the solubility of this pigment it may be possible that when tap water is used to water potted plants the Sodium hydroxide that it can contain results in sclerotia that lose the yellow colouration and appear white. Possibly reactions could also occur with naturally occurring hydroxide ions produced in water as a result of an ionisation reaction or with other substances either added to drinking water, such as chloramine or chlorine or found naturally in it such as various dissolved minerals.

Mattirolo notes that the sclerotia of Lepiota flos-sulphuris and of Lepiota incerta were confused by previous authors due to both living on the same substrate in greenhouses. However his own study was also conducted in this environment with attempts to culture either the sclerotia or mushrooms being unreliable and failing due to contamination. Therefore the bulk of his observations were made on specimens growing in the greenhouse and the associated sclerotia were identified by their proximity or attachment to the mushrooms rather than through observation in isolated cultures.

Fig. 7 - Yellow pigment of L. birnbaumii sclerotia diffusing in KOH Observation 176917949- L. birnbaumii and L. ianthinus Credit: @tx_tea

Since Mattirolo's work is comprehensive and was conducted over many years with sclerotia illustrated at the base of the mushrooms and as the appearance of dried Lepiota incerta is compared to other herbarium specimens, it seems safe to rule out these species simply being the same.

It is however worth noting that he was never able to successfully culture the sclerotia to produce mushrooms and every attempt to grow them, by his own admission, succumbed to contamination and failed. He was able to demonstrate that no conidia were present on the sclerotia, as other authors had claimed, by observing their growth for years in the greenhouses of Turin and Florence. He was regrettably not able to further study their growth in isolation however due to cultures failing. He describes his attempts at cultivation as fruitless despite trying many times over the years.

The main issue that plagued Mattirolo's efforts to culture these species appears to be a combination of contamination and perhaps less than ideal substrates. He tried sphagnum moss, grapes, plums, terra di castagno and 'various jellies' or gelatines though does not mention what processes were used to sterilise these substrates or to provide a sterile growing environment. He describes sclerotia and cultures readily falling prey to mold, often after the appearance of colourless 'brilliant' water droplets/exudation which turned yellow and opaque followed by mold appearing.

In a culture of Leucocoprinus cretaceus grown on malt extract agar I observed similar exudation appearing shortly after the development of the sclerotia, which were produced in abundance compared to the water agar formula that had little growth. The droplets were at first crystal clear and gave the top of the substrate a brilliant, glistening appearance like early morning dew on grass. They persisted for several days and grew to a similar size as the sclerotia themselves before some yellow orange discolouration occurred within the liquid. These droplets ultimately disappeared, either through evaporation or reabsorption leaving the sclerotia looking dry, however no contamination occurred within this culture. The exudation appears to be related to the development of the sclerotia and the result of losing water as they mature, harden and dry. This has only been noted on agar however and not observed in jars of rice, wheat bran or wood so it is unclear if it is affected by the saturated substrate providing excessive water. Such exudation is commonly remarked upon in studies of sclerotia in many different species however and appears to be a common trait.

Mattriolo's experimentation appears limited by the tools, materials and knowledge of the era. He notes that attempts to cultivate cultures from isolated sclerotia only resulted in contamination whilst cultures from myceliated substrate were able to produce new mycelium and hyphal knots that formed into small sclerotia, before they too fell prey to contamination. The sclerotia production never reached that which happened naturally in pots in greenhouses even when attempts were made to control the temperature.

It may be for this reason that he stated that Lepiota cretacea (now known as Leucocoprinus cretaceus) did not produce sclerotia since they are not easily observed in specimens growing naturally in soil but are readily apparent in cultures, especially in high nutrient substrates.

In his observations of the species that he described as Lepiota flos-sulphuris, Mattriolo notes that the sclerotia and mushrooms are only observed on the Sphagnum moss lining the tops of pots after they have been in the pot for at least one year. He states that if the moss is removed and replaced with new moss it takes another year before sclerotia or mushrooms reappear. He also notes similar with the growth in terra di castagno when used to cultivate tropical plants.

These observations match those we see today with people regularly noting mushrooms or sclerotia only appearing in their plant pots after they've already had the plant for several years, which adds to their surprise and confusion when they find them. It is also important to note that Mattriolo was writing from a time before the modern potting soil mixes we use today were formulated. Commercially available potting mixes comprised of peat moss wouldn't arrive until the 1960s and it is only more recently that coco coir has come to replace this out of environmental concerns. Earlier observations of Leucocoprinus species almost always note bark beds as these were commonly used in hothouses however Sphagnum, terra di castagno and modern potting soil mixes may provide a more ample habitat that encourages greater production of sclerotia. These substrates may provide a similar environment to the light, airy and moist topsoil of rainforest floors and are likewise rich in undigested organic material. This could explain why the sclerotia of Leucocoprinus birnbaumii are observed so readily today yet were not so commonly remarked upon in earlier observations.

2.5. Cenococcum xylophilum & Leucoagaricus meleagris

There are some additional descriptions which resemble the sclerotia of L. birnbaumii which were not covered by Mattirolo. In 1829 Fries described the Cenococcum genus as containing two species with C. geophilum citing Sowerby's Lycoperdon graniforme as a synonym and C. xylophilum as a new species. Cenococcum are described as small black balls about the size of vetch seeds which are not rare but are easily overlooked amongst black soil. At first the interior is similar to the exterior but then becomes filled with powdery spores and leaves a hollow in the centre with brown spores noted in C. geophilum and white spores in C. xylophilum. However no spore measurements or descriptions are otherwise given.[31]

Lycoperdon graniforme was found in woodland in England where it appeared like shot pellets lying on top of the ground. They were brittle and cracked easily revealing a black powder and are illustrated as little more than rough black balls containing this powder.[32] This can surely be disregarded as Leucocoprinus sclerotia however as the description of Cenococcum xylophilum is heavily based on direct comparison with C. geophilum it was necessary to explore this.

C. geophilum was found in England amongst beech woodland or dried up basins in Autumn and a variant is also noted from France. C. xylophilum is described as having a pale purplish floccose thallus with mature peridia that are only loosely attached. The outside is said to be similar to sclerotium but the inside is floury whitish. It was found in woodland in Petropoli, Russia.[31]

The sclerotia of C. geophilum are similar in appearance to the sclerotia of Leucocoprinus cretaceus appearing as they do as small black balls. However as it is an Ascomycete fungus that is ectomycorrhizal this is clearly unrelated.[33]

In 1900 Jean Louis Émile Boudier and Narcisse Théophile Patouillard reclassified Cenococcum xylophilum as Coccobotrys xylophilus. It was noted as being a true sclerotium and described as having minute 1-2mm wide, hard irregularly round or pear shaped structures with an ochreous-yellow exterior with a black surface beneath followed by a reddish layer under that and a paler centre. This centre area is more friable with a pale ochreous colour that often turns red or whitish when it dries out. They were found during April in bark beds in a hothouse growing palms. These numerous growths arise from rhizomorphic mycelium that is ochreous-fawn in colour. The outer layer of the sclerotium is said to be exfoliated by boiling lactic acid and not coloured by the addition of a hot solution of cotton blue added to the acid. The interior of the cells is filled with granular protoplasm which starts white before becoming ochraceous. The protoplasm is stained with iodine in the same manner as glycogen/starch. The granular structure simulates the appearance of spores though Boudier and Patouillard do not describe finding any spores and since no mushrooms are described it does not appear that fruiting bodies were observed and associated with the sclerotia.[34]

The colour, hardness and habitat described here as well as the black and ochreous-yellow layers does sound like the sclerotia of L. birnbaumii. However the size given is much larger and it is unclear what the repeated mentions of a red colour refer to. The French text only says 'rouge', several times and the Latin uses 'rufis' so it is not clear what particular shade is being described. Reddish brown could be an adequate description of the orangy brown colour seen prior to the black colour developing in the sclerotia of L. cretaceus and when L. cepistipes is cultured on agar a reddish brown colour is sometimes present in the old mycelium surrounding the sclerotium, with similar noted in descriptions of some Coprinopsis species however this colour is more brown than red.

Coccobotrys xylophilus is described as being very reminiscent to the Emericella genus with a citation that points to Patouillard's Emericella variecolor (now known as Aspergillus stellatus). The similarity that is referenced appears to be the presence of the hairy, yellowish, globose or pear shaped tubers which are 1-3mm high and scattered or grouped on rotten wood.[35] However it is noted that C. xylophilum is very different from this species by virtue of the sclerotia.

In 1900 Charles van Bambeke described the 'very rare and hardly known spherical grained mycelium' of Coccobotrys xylophilus as an asexual morph belonging to Lepiota meleagris (now known as Leucoagaricus meleagris). The specimens studied by Bambeke were found growing on the tan bark in a hothouse in Belgium. Little further detail is added to describe them.[36]

However it is noted by Else Vellinga that the material examined by Boudier and Patoulliard and Bambeke was not the same as the Cenococcum xylophilum examined by Fries.[37] This is indeed very evident by the differences in the descriptions given and as such it is unclear which species were being described by these authors, suffice to say that some of them do resemble the sclerotia of a Leucocoprinus species.

2.6. Additional studies

In 1948 Karel Cejp reclassified Mattirolo's Lepiota flos sulphuris as Leucocoprinus flos-sulphuris and Lepiota incerta as Leucocoprinus flos-sulphuris var. incerta. Cejp personally observed L. flos-sulphuris growing in greenhouses as well as L. cretaceus, L. cepistipes and L. meleagris. Little further information is provided on the sclerotia of L. flos-sulphuris however and sclerotia were not observed in any of the other species.

Cejp states that L. flos-sulphuris can be easily confused with the similar yellow species described from greenhouses Leucocoprinus luteus (With.) Pat. and Lepiota lutea (With.) Godfrin. He notes that the authors of them were probably not familiar with the sclerotia always created by L. flos-sulphuris but goes on to state that Agaricus cepaestipes and Agaricus cretaceus did not produce sclerotia.[11]

This speaks to the distinctive nature of sclerotia in Leucocoprinus birnbaumii such that they are far more easily observed than those of L. cepistipes or L. cretaceus which would be easily missed without culturing these species.

Cejp states that Corda's Agaricus birnbaumii is probably identical to L. flos-sulphuris. His reclassification of Lepiota incerta does not appear to have been based on personal observation however and no further information was provided on this species with Cejp stating that it differs only in the colour of the mushrooms. Cejp also says that Leucocoprinus flos sulphuris var. nigrescens-minor is a variety which is just a coloured form with mainly black coloured scales on the cap. The citation given points to Agaricus cepaestipes var. nigrescens Baglietto[38] but there does not appear to be any information in this description to assume an association with L. flos-sulphuris. There does appear to be a variant or species similar to L. cepistipes but with a darker centre to the cap which is seen occasionally in observations so this is likely what Baglietto was describing.

A study in 1962 was successful in culturing sclerotia of Leucocoprinus luteus (now considered a synonym of L. birnbaumii) on wheat chaff until they fruited. Warcup and Talbot state that they were unable to determine whether sclerotia had previously been noted in this species. However they cite L. cepaestipes as a similar species that possesses pale or light yellow sclerotia so this may just be another example of the taxonomy being confused with these species.[39]

In 2011 a study on sclerotia of L. birnbaumii found in a plant pot in Japan confirmed via genetic sequencing that the sclerotia were the same species as the mushrooms.[2] This study does not cite any of the sources used here that reference sclerotia or any of the early descriptions of the Sclerotium species so it seems that the authors were unaware of them. This would not be surprising as this study appears to be the only modern one which discusses sclerotia in a Leucocoprinus species in any detail.

3. Sclerotia in Agaricales

The 2014 study 'How many fungi make sclerotia?' provides an excellent place to start researching sclerotia with many sources collated. When it comes to Agaricales the list of species is short and incomplete but it does provide some genera to research further. The study lists the following saprotrophic Agaricales as producing sclerotia: Leucocoprinus luteus, Pleurotus tuber-regium, Coprinus lagopus, Coprinopsis sclerotiorum, Agrocybe arvalis, Psilocybe caerulescens, Stropharia tuberosa, Collybia tuberosa, Omphalia lapidescens and an unnamed Rimbachia species with a citation to the same Warcup and Talbot study that documented sclerotia in Leucocoprinus luteus, however I've been unable to find a description of it in that study. Three ectomycorrhizal species are also listed: Cortinarius calochrous, Hebeloma sacchariolens and an undescribed Entoloma species first documented in 'How many fungi make sclerotia?' Additionally one plant pathogen, Typhula incarnata is listed from the Agaricales.[1]

Many of these species, or their close relatives are common to find in potted plants. If it is to be considered that the sclerotia of L. birnbaumii may facilitate distribution of this species via potting soil, compost and potted plants then it is also necessary to explore the growth habits of other sclerotia producing species to evaluate whether sclerotia production appears to correlate with growth in potted plants in other species. Additionally such an investigation can reveal whether species in any other genera produce sclerotia similar to those of L. birnbaumii.

The iNaturalist potted plant mushrooms project has been collated manually via a mix of keyword searches, manual review and casual browsing. It is not a complete list of species found in plant pots and for many reasons does not and cannot provide a perfectly accurate representation of which of these species are the most common. For instance whilst Leucocoprinus birnbaumii is almost certainly one of the most common mushrooms to find in plant pots it is also one of the most spectacular, eye-catching and distinctive. People may be more likely to upload photos of this bright yellow mushroom that shows up and surprises them whereas the drab mushrooms produced by many species in the Psathyrellaceae family may not warrant so much attention, especially not after becoming used to them routinely showing up with seedlings every year. The project does however provide a useful reference for which species are typical to find in plant pots and which are not and enables easy comparison of these observations.

It would be remiss of any discussion on sclerotia not to mention H. J. Willetts comprehensive 1971 study 'The survival of fungal sclerotia under adverse environmental conditions'. This study covers commonalities observed amongst sclerotia such as the presence of melanin in the rind, the exudation of droplets observed during maturation as well as the potential resilience to contamination and extremes of heat and cold.[40] As such it is an invaluable tool in studying sclerotia despite it primarily being focused on plant pathogens, which are beyond the scope of this review. Coprinus stercorarius is briefly mentioned however. Other taxa that are discussed by Willetts with citations to studies on their sclerotia are:

Alternaria solani, Aspergillus, Aspergillus alliaceus, Aspergillus alliaceus, Aspergillus nidulans, Aspergillus phoenicis, Botrytis allii, Botrytis cinerea, Botrytis convoluta, Botrytis fabae, Ciborinia, Claviceps, Claviceps purpurea, Colletotrichum coccodes, Cordyceps, Fusarium solani, Helminthosporium sativum, Macrophomina phaseoli, Mucor hiemalis, Mycosphaerella ligulicola, Neurospora crassa, Papulospura, Phymatotrichum omnivorum, Pyronema domesticum, Rhizoctonia solani, Sclerotinia, Sclerotinia fructicola, Sclerotinia fructigena, Sclerotinia gladioli, Sclerotinia laxa, Sclerotinia laxa f. mali, Sclerotinia libertiana, Sclerotinia sclerotiorum, Sclerotinia trifoliorum, Sclerotinia (Monilinia) spp., Sclerotium cepivorum, Sclerotium rolfsii, Typhula, Typhula gyrans, Typhula intermedia, Typhula sclerotioides, Verticillium, Verticillium albo-atrum, Verticillium dahliae.

3.1. Sclerotia in Psathyrellaceae

Sclerotia appear to have been documented more extensively in Coprinoids than in Leucocoprinus species with numerous common species producing tiny sclerotia with traits similar to those seen in Leucocoprinus species as well as some with far larger sclerotia. Psathyrellaceae are very common finds in plant pots with numerous species across many genera routinely appearing in potting soil. Generally they appear to differ in behaviour from Leucocoprinus species with Coprinoid mushrooms often showing up in freshly moistened soil used to start seedlings whereas Leucocoprinus seem more common in older houseplants.

Coprinopsis lagopus has been documented as producing sclerotia with the purpose attributed to remaining dormant until favourable conditions for germination arise.[41] A study in 1975 on agar cultures described the mature sclerotia as dark brown to black spheroidal structures up to 0.5 mm in diameter with a difference noted between the hyaline interior flesh (medulla) and the outer rind. Sclerotia produced submerged in the agar as opposed to those in the aerial mycelium were noted as being larger at 0.5-1 mm in diameter with an irregular shape and pale brown colour. The rind was suggested as serving as a protective layer for the interior flesh during conditions adverse to normal growth and an extreme outer layer of dead hyphal cells was noted that was thought to be the product of surplus materials during sclerotial develop and presumed not to serve a purpose. This study however considered Coprinus cinereus (now known as Coprinopsis cinerea) to be synonymous with Coprinus lagopus (Coprinopsis lagopus) so it is unclear which species was studied.[42]

When different strains of Coprinopsis lagopus were cultured the majority produced sclerotia with marked differences in the number produced by different strains. Some strains were unable to produce sclerotia and four genes were identified as being involved in the production of sclerotia.[43]

Coprinopsis lagopus has thousands of observations on iNaturalist, though as this species is more commonly known than others it is likely that some observations may be for similar species. There are numerous, morphologically similar or identical species in Coprinopsis sect. Lanatulae[44] but iNaturalist has vastly more observations identified as Coprinopsis lagopus than it does ones left at the section level or identified as any of the other species within this section. Nonetheless there are many observations of Coprinopsis lagopus in plant pots.

Coprinopsis cinerea was isolated from rice husks and when cultured was documented as producing brown, globose to ellipsoidal sclerotia which are 70-180 (200) μm in diameter with a rind comprised of yellow to dark brown pseudoparenchymatous tissue. The internal medulla is comprised of pale brown prosenchymatous tissue.[45]

These are overly not common terms to encounter and indeed this study in some instances uses the term 'pseudochymatous', perhaps erroneously as this yields few results when searched. So it seems necessary to define these terms since they are routinely used in descriptions of sclerotia and speak to the commonality between the features of sclerotia in disparate species.

Pseudoparenchyma is defined by the Collins dictionary as 'a compact mass of tissue, made up of interwoven hyphae or filaments, that superficially resembles plant tissue'.

Prosenchyma is defined by the Collins dictionary as 'a plant tissue consisting of long narrow cells with pointed ends: occurs in conducting tissue'.

This terminology is perhaps not ideal for describing features in fungi rather than plants but they are used commonly enough and they do serve well to distinguish the appearance of the interior and exterior flesh of sclerotia. Whilst both the external and internal tissue of sclerotia that are crush mounted have a highly cellular pattern they are easily distinguished from each other visually by the shape and appearance of this pattern.

Coprinopsis cinerea has also been cultured from rice husks in iNaturalist observation 152704280 by @raingel. Observations for this species are otherwise quite few and none appear to be from plant pots. Similar sclerotia have been documented in Coprinopsis sclerotiger having been isolated from elk dung and cultured on agar[46] however this species is poorly known with only a single observation on iNaturalist at present.

The brown colouration of the external rind in Coprinopsis cinerea may be attributed to the presence of melanin.[47] This may be universal to sclerotia with melanin also noted in other studies and potentially providing the sclerotia with some of their resilient characteristics. The presence of melanin was noted previously in a study on the snow mold fungus, Coprinus psychromorbidus (now known as Coprinopsis psychromorbida) where melanin was found in the outer layer of the rind cell walls via scanning electron microscopy and electron imaging. The black pigment of the mature sclerotia was soluble in KOH, insoluble in water, acetone and ethanol and bleached after 24 hours of immersion in sodium hypochlorite or hydrogen peroxide. A size range does not appear to be given for these sclerotia but the microscopic images show them to be ~500μm in diameter. The optimal temperature for production of sclerotia was 20-25°C, higher than the 10-15°C that was optimal for mycelial growth.[48] In this species then it appears that sclerotia could serve as a means of surviving less than optimal temperatures for growth.

Coprinopsis sclerotiorum is documented as producing irregular, subglobose, dark brown sclerotia that are far larger than others at around 10 mm in diameter which then become 35 x 10 mm and finger shaped.[49] Large sclerotia in a Coprinopsis species have also been documented in iNaturalist Observation 125136438 by @corndog.

A fascinating case of similarly large sclerotia in a Coprinopsis species becoming an industrial contaminant was presented in 1974 when Coprinus stercorarius (now known as Coprinopsis stercorea) was documented producing sclerotia which clogged pipes in the effluent treatment tower of a winery in Australia. The sclerotia had a size of (4) 6-12 (15) mm and circular depressions of 1 mm scattered on the surface rind, which was dull black when dry or shiny black when moist with a white interior when dissected. When moist they had a rubbery texture but became hard and wrinkled after a long period of drying. In a laboratory setting, the mushrooms grew directly from the surface of the large sclerotia with 1-4 per sclerotium. The winery effluent was comprised of spent wash water and lees from the wine making process which had been stored in open dams for 3-4 months before being pumped into the treatment tower. Sodium carbonate was added to adjust the pH to 7 before the liquid entered the tower and urea was drip fed into the liquid to add nutrients to aid bacterial growth. It was hypothesised that the fungus entered the liquid from grazing paddocks surrounding the stored liquid. Sclerotia growth was prevented by removing the urea drip feed. The species was presumed to be synonymous with Coprinus sclerotianus though the sclerotia in that species were described as being 3-6mm in diameter. It was hypothesised that they may have grown far larger owing to the high levels of nutrients provided by the liquid.[50] However considering the numerous Coprinopsis species documented as producing sclerotia it seems possible they may just have been similar species with different sclerotia characteristics.

In 1987 a study on the sclerotia of Coprinus congregatus (now known as Coprinellus congregatus or Tulosesus congregatus) documented the production of sclerotia in liquid culture and noted that the hyphal knots of both the sclerotia and primordia were indistinguishable. The sclerotia formed in liquid culture were noted to be identical to those formed on agar and it appeared that the presence of bacteria, even in low levels that were not easily detected induced the formation. It demonstrated that sclerotia formed in light or dark in liquid culture or agar but that primordia only formed on agar in the presence of light.[51]

These studies on sclerotia in Coprinoids provide a wealth of useful information with many characteristics that are shared between the sclerotia of different species, including some Leucocoprinus species. For example the sclerotia of Leucocoprinus cretaceus develop a dark brown to black surface at maturity which could also be due to presence of melanin. The cellular pattern found in the rind and the internal flesh are similar in appearance so can likewise be described as pseudoparenchymatous and prosenchymatous. These similarities are also found with the sclerotia in other families but are not confined to just sclerotia.

3.2. Sclerotia in Hymenogastraceae

Observations of Hymenogastraceae from plant pots are fairly common on the whole with several Gymnopilus species appearing regularly even in indoor plant pots suggesting a spread via the potting soil or with commercially bought plants. With the notable exception of Psilocybe angulospora which has many observations from potted plants in New Zealand, Psilocybe species don't appear especially common in potted plants though several species do have a few observations each with many more left at the genus level. Agrocybe species also do not seem overly common but some species do show up in plant pots outside. Observations of Galerina or Kuehneromyces species in plant pots do not seem very common. It would appear that whilst many species in this family can grow in plant pots few are likely to spread in this manner given the dearth of observations.

In some observations of Gymnopilus species web like mycelium and small spheres can be seen around the base of the mushroom and on the surrounding substrate. In wild specimens growing from logs many of these are readily explained by the presence of other fungi but in some instances the mycelium does appear to have a similar colour and consistency to L. birnbaumii. However in plant pot specimens whilst there are compelling observations like observation 182132098 by @barefootmark which look very similar to the sclerotia of L. birnbaumii it seems probable that if such structures are sclerotia then they likely actually do belong to L. birnbaumii as in observation 178211973 by @jtanks the two species can be seen growing adjacent to one another in a plant pot. There does not appear to be any documentation on sclerotia in Gymnopilus species.

The Hymenogastraceae family though does contain some well known sclerotia forming species including Psilocybe tampanensis, P. mexicana and P. semilanceata with the sclerotia hypothesised as a mechanism for surviving grassland fires.[52]

In an experiment by Roger Heim the sclerotia of Psilocybe mexicana were found to form more abundantly in darkness whilst the fruiting bodies only emerged if the substrate was exposed to light.[53] This is suggestive of formation underground in nature and with their size and appearance being similar to that of walnuts they do appear to be good mechanisms for survival. P. atlantis is a similar species that also produces sclerotia[54] and P. caerulescens is also said to produce sclerotia[55] however as this species is sometimes cultivated and sclerotia are not reported it is unclear if this is correct. The source cited by "How many fungi make sclerotia?" for P. caerulescens does not provide details on the sclerotia of this species and the sources it is citing for it are not readily available online to check.

The sclerotia size seen in P. mexicana and P. tampanensis would not appear to make for practical transport between plant pots as the large stone like structures would be more readily sieved out or removed and aren't produced in such substantial numbers as to become widely distributed. However as sclerotia have primarily been documented in Psilocybe species due to their desirability to cultivate and as such information dominates search results it is unclear if smaller sclerotia have been documented in other species.

Hypholoma tuberosum was described from mulch beds and compost in Vancouver, Canada. The sclerotia were formed where the soil met the mulch and described as having irregular subglobose, ellipsoid or oblong sclerotia that were often lobed. They measured 85 x 50 x 45 mm and had a tough, dry, brown outer rind with a greyish yellow brown or dark greyish yellow interior and some ochraceous areas.[55] This was compared against Stropharia tuberosa and Agrocybe arvalis as well as the Psilocybe species known to produce sclerotia since these were placed in Strophariaceae at the time.

This species was reclassified as Psilocybe tuberosa in 1998 by Ruben Walleyn having been found in Belgium.[56] However a species was already described under this name in 1904 by Petter Adolf Karsten making this classification illegitimate. Karsten did not described the sclerotia of his species in detail beyond saying that the mushrooms emerged from white tubers in the earth.[57] Based on the description of the mushrooms however this species is thought to be a Psathyrella species though it was never reclassified as such. Subsequently Hypholoma tuberosum was reclassified as Psilocybe tuberifera.[58]

The species has also been documented in Australia as Hypholoma tuberosum with sclerotia measuring 50 x 40 x 20mm in diameter found in a peat and soil mix. The specimens studied by Priest and Simpson came from potted ornamental trees in commercial premises in Sydney after the occupants objected to the presence of the mushrooms which frequently appeared around the plants. Examination determined that the mushrooms were fruiting from the sclerotia which were associated with coarse pieces of peat. Additional specimens were collected in dry areas of peat bog and from sandy margins of a creek. In this instance sclerotia and fruiting bodies were only found in sand deposits directly adjacent to the water. The study also noted that in the vicinity of the Georges Creek by which the sclerotia were found there were numerous commercial nurseries. It was hypothesised that the specimens found growing beside the water were the result of sclerotia that had been screened out of peat by a commercial nursery located within the watershed. Commercial peat in the region was derived predominately from sedges rather than sphagnum though sphagnum based peat had been imported in the past from Europe or New Zealand. A connection to Canada via imported peat or potted plants was not found. The sclerotia were potted in soil in a greenhouse and germinated to produce mushrooms.[59]

The authors of the study questioned what role sclerotia served in nature and it was considered that if the peat were the natural habitat of H. tuberosum then the sclerotia would serve as an ideal mechanism to store nutrients and survive the dry periods in which mycelial growth would not be possible.[59]

Hebeloma sacchariolens is documented as having conspicuous white sclerotia which are globose, subglobose or flattened and 200-400 μm in diameter. These are found adhered firmly to the mantle surface of the mycorrhiza. The same study also documented sclerotia in Paxillus involutus but described these as loosely connected to the mycorrhiza.[33]

The sclerotia of H. sacchariolens lack the dark pigment and thick rind of many other species with only a thin wall surrounding an internal pseudoparenchymatous structure containing large amounts of lipids, which are hypothesised to serve as a store of energy. When sclerotia were detached from host roots and buried in moist soil they remained viable for at least 40 weeks and when introduced to birch roots after this time were still able to develop mycorrhiza and exclude other mycorrhizal fungi. Sclerotia examined after being buried in soil for 16 and 40 weeks were noticeably softer though retained their white colouration and structural integrity. After inoculation from sclerotia new sclerotia were observed to have grown within the 16 week period of the study.[60]

There are a few observations of Hebeloma species in plant pots on iNaturalist but as they are mycorrhizal these are of course only where trees are planted in pots. However it may also be interesting to note that the gasteroid genus Hymenogaster are very similar in appearance to the sclerotia of Hebeloma sacchariolens with their smooth exterior surface and an interior which has a similarly pseudoparenchymatous appearance. Hymenogaster are not sclerotia however and this internal structure is a sporulating surface. The Psilocybe genus likewise contains some gasteroid species such as Psilocybe weraroa which when bisected has an appearance vaguely similar to the fruiting bodies of Hymenogaster species and the sclerotia of Hebeloma sacchariolens. Since sclerotia and fruiting bodies both emerge from hyphal knots the similarities in appearance are intriguing. Tympanella galanthina is a sectoid fungus in the Hymenogastraceae family which also has some observations in plant pots in New Zealand.

In the Ascomycete family Tuberaceae an evolutionary lineage between surface fruiting bodies and truffles has been hypothesised whereby arid conditions selected for fruiting bodies that were more enclosed, so as to reduce water loss. According to the theory, this selective pressure then lead to the loss of the ability to forcibly discharge spores resulting in distribution of spores via animals instead. Further selection along this line resulted in truffles which fruit below ground and contain a solid gleba containing spores.[61] Given the similarity in appearance between some of the sectoid or gasteroid fruiting bodies and sclerotia in the Hymenogastraceae family it may be interesting to consider a similar evolutionary forcing.

The sclerotia of Agrocybe arvalis are evidently quite large and readily found with numerous iNaturalist observations documenting them including observation 35811272 by @heelsplitter, 146456608 by @hiroko_s and 95141398 by @leptonia. Whilst Agrocybe species are sometimes documented in plant pots these appear to be in outside pots where introduction via spores over time is more likely than the fungus having come with soil. There are currently no observations of Agrocybe arvalis from plant pots and sclerotia of this size would not seem like such an ideal distribution mechanism between plant pots.

Agrocybe arvalis has a taxonomic history which includes several basionyms as the species is evidently common enough to have been described independently several times. The specific epithets for several of the synonyms indicate that the sclerotia were the typifying feature. Naucoria tuberosa was reclassified as Agrocybe tuberosa while Galera arvalis var. tuberigena was reclassified as Agrocybe tuberigena and Naucoria arvalis var. tuberigena. The description for Naucoria tuberosa notes that the mushroom emerged from a hard, almost spherical, wrinkled, black sclerotium that was about 1.5-2cm in diameter with a white interior when cut.[62] The sclerotia were not documented in the original description of Agaricus arvalis.[63]

Due to their similar appearance some genera in Hymenogastraceae were previously classified as Strophariaceae and confusion can still occur when identifying them. This is also seen in some accounts of the sclerotia like structures in Strophariaceae.

3.3. Sclerotia in Strophariaceae

Stropharia species do not seem to be a regular occurrence in plant pots with no definite observations on iNaturalist collected to date besides cultivated Stropharia rugosoannulata. Strophariaceae do not seem to be typical to find in plant pots in general. Leratiomyces ceres appears to have more observations from plant pots than everything else in the family combined, however observations of it from plant pots are few and far between when browsing through the thousands of observations of this species. Sclerotia, or structures similar to them have been documented in some species in the Strophariaceae family although they appear to be considerably larger than the small sclerotia common amongst the Coprinoids and Leucocoprinus species and as such are unlikely to be readily transferred in potting soil.

Stropharia tuberosa was described in 1918 by Henry Curtis Beardslee in Curtis Gates Lloyd's Mycological notes. Specimens were found growing in masses of old cow dung in the woods in West Virginia. They were compared to Stropharia umbonatescens and S. mamillata but differentiated by the spore size as well as the sclerotium, which every specimen of Stropharia tuberosa was found to emerge from. A size range is not given for the sclerotia but the photograph shows a large solitary sclerotium which appears ~2/3 the size of the cap of the mushroom, the size range for which is given as 2-4 cm. From this photo then the sclerotium appears to be ~1.3-2.6 cm wide. The thickness of the stipe is given as 3-4mm[64] which by chance are the widths I find from measuring the bottom of the stipe on my screen at the default resolution and fullscreen view from the source on the internet archive. Measuring the sclerotium in the same manner produces a size of ~1.5-2.3 cm.

Lloyd notes that Naucoria scleroticola which was also found in West Virginia and published in an earlier edition of Mycological notes appears similar and that since its publication Jakob Emanuel Lange had communicated that Naucoria arvalis also sometimes developed from sclerotia.[64] Naucoria arvalis is now known as Agrocybe arvalis and whilst Naucoria scleroticola has not been reclassified nor was it ever formally described as such as it was considered to be so similar in appearance to Naucoria semiorbicularis as to potentially simply be the same species, only growing from a sclerotium. As such the 'description' of this species specifically states that they are not describing a new species and it was thought that the sclerotium could be an occasional occurrence. The specimens were sent to Lloyd by Reverend Boutlou who noted that all of the Naucoria in his garden had sclerotia and that these ultimately dried up and became hollow leaving only hard skin behind.[65]

Naucoria semiorbicularis is now known as Agrocybe pediades and so it appears that this was an account of sclerotia in an Agrocybe species however Stropharia tuberosa was considered distinct as it differed in the gill colour amongst other features. Stropharia tuberosa was reclassified as Protostropharia tuberosa in 2014 however as this was only an Index Fungorum nomenclatural novelties update which reclassified four species as Protostropharia no additional information was provided on the species or the sclerotia produced by it.[66] The holotype of Protostropharia tuberosa may be the only preserved specimen that exists and the species is considered rare and poorly known. The 'sclerotia' formed by it may in fact be pseudosclerotia with similar structures sometimes found in Protostropharia alcis ssp. austrobrasiliensis. Pseudosclerotia were not observed with P. dorsipora or P. semiglobata.[67]

These are the two most commonly observed Protostropharia species on iNaturalist and whilst it is likely that P. semiglobata contains observations for other species due to it simply being the most commonly known, other species in this genus do not have many observations. Observations of Protostropharia alcis on iNaturalist are relatively few but frequently show mushrooms growing from elk or moose dung such that they have a similar appearance to the mushrooms growing from sclerotia however it is unclear if such structures are contained within the dung or if the similarity is simply coincidental. Regardless it could make documentation of the sclerotia, or pseudosclerotia in these species less common due to people either dismissing them as dung or being unwilling to dissect said dung in order to explore further.

Pseudosclerotia are also documented in Protostropharia luteonitens with these structures distinguished from sclerotia by the presence of pieces of substrate within the medulla, or internal flesh. The manner in which sclerotia and pseudosclerotia form is distinct with sclerotia forming from hyphal knots in the same way that mushrooms form whereas pseudosclerotia are cut out from the substrate by pseudosclerotial plates.[68] In wood rotting species like Armillaria mellea pseudosclerotial plates are the 'zone lines' seen in a cross section of infected wood with these lines representing a sectional view of the outer rind of the forming pseudosclerotial body.[69] A simplistic way to conceive of the difference may be to consider a sclerotium as forming and displacing the substrate as it grows outwards whereas pseudosclerotia subsume the substrate as they grow inwards such that it becomes incorporated into the pseudosclerotial mass.

The hyphae inside the pseudosclerotia may then continue to digest the substrate resulting in partial or complete replacement of the substrate with hyphae. Subsequently the volume of substrate contained within pseudosclerotia varies and if no substrate remains then it may not be possible to distinguish them from sclerotia. The pseudosclerotia of Protostropharia luteonitens are described as almost black, with an irregular bean or potato shape measuring 8-15mm long and white interior flesh composed of compact hyphal masses. The exterior rind is composed of thick walled, dark brown polyhedral cells and measures 25-40 μm thick but is brittle making it hard to section. The rind does not dissolve in 10% sodium hydroxide though a crush mount in this reagent reveals the presence of small crystals. When sulphuric acid is applied needle like crystals are formed indicating calcium content. The rind stains weakly with Congo red but is unreactive with many other stains including several blue stains and Melzer's reagent. Sclerotia were not mentioned in Lucien Quélet's 1888 description of Stropharia luteonitens though he did note occasional sclerotia in Stropharia stercoraria (now known as Protostropharia semiglobata). This study also suggests that the differentiation in aerial and submerged sclerotia observed in cultures in Coprinus cinereus may represent the presence of both sclerotia and pseudosclerotia.[68] The example given is for Coprinus cinereus however the citation is for the 1975 study on Coprinus lagopus, though this study did consider the two species synonymous.

Considering that pseudosclerotia are likely even less well known than sclerotia and that their irregular appearance, dark exterior surface and the pieces of plant matter that they contain can give them an appearance like dung, especially where large amounts of partially decomposed plant matter is present, it seems possible they may be under-reported. After reviewing this material I made a chance observation of structures which appeared to be pseudosclerotia in a wormery which had been started from a contaminated tub of cultivated Ganoderma lucidum. The structures had a similarly thin, brittle dark exterior surface as described here with a distinctive crunch when broken. The material contained within them was the only material in the wormery that had not been consumed by the worms, isopods, springtails and other creatures living in the substrate. Whilst the exterior was thin and brittle it appeared effective at keeping these creatures out enabling some mycelium to survive within. These structures would easily have been overlooked if this review had not been conducted prior to collecting material from the wormery as it would not have been clear what they were.

3.4. Sclerotia in Pleurotaceae

Pleurotus tuber-regium is documented as producing rather large, edible sclerotia which are consumed in Nigeria and readily available to purchase in markets. Subsequently there are many papers about the sclerotia in this species (often under the name Pleurotus tuberregium) regarding nutritional content, medical value and cultivation but there does not appear to be documentation of sclerotia in other Pleurotus species. It is regarded as the only known sclerotia forming species in the Pleurotus genus as such its classification in this genus is questioned.[70]

The sclerotia are globose to ovoid and can reach 30cm or more in diameter. In studies on the nutritional content, potassium was found to be the most abundant mineral in the cultivated sclerotia, in most cases followed by sodium with the magnesium, calcium and phosphate content varying by substrate. Sclerotia production started in culture 5-6 weeks after spawning and growth continued until they were harvested 14 weeks after spawning, by which point they had turned light brownish. Sclerotia remained viable and able to produce fruiting bodies after 9 months storage in the refrigerator at 12°C.[71] iNaturalist contains many observations of this species, especially from Australia and the large sclerotia are frequently visible on top of the leaf litter or wood with mushrooms growing directly from them.

Pleurotus species do not seem to be commonly observed in plant pots, except in cases where cultivated substrate has been buried however there are many observations on iNaturalist of Hohenbuehelia petaloides in plant pots. Potentially this is another case of this species being more well known than others such that observations for it actually include those for several species but such observations do at least seem to be for Hohenbuehelia species. They appear relatively common to find in indoor plant pots suggesting spread via the potting soil.

3.5. Sclerotia in Galeropsidaceae

Panaeolus species appear to be reasonably common to find in plant pots with Panaeolus cinctulus being the most common ID given, though whether these IDs are correct or the result of this species simply being more well known than others is not clear. Sclerotia or pseudosclerotia are sometimes observed in cultivated P. cinctulus and they appear to contain psilocybin given the blue colouration, resulting in them sometimes being quite noticeable to observers. Similar observations exist for sclerotia in P. tropicalis and possibly some otherwise unnamed Panaeolus species that have been cultivated. However sclerotia do not appear to have been formally described or studied in these species and are not observed universally so the nature of these structures is unclear.

Sclerotia have been described in Panaeolus subbalteatus with greenish blue sclerotia forming abundantly when cultured on agar. When established mycelium was transferred to a Petri dish of malt agar or other mediums, large drops of exudation appeared after five days along with sclerotia. When first observed these were initially thought to be contamination by Penicillium owing to the striking blue green colour however examination revealed them to be sclerotia. They were spherical and ranged from 1-4mm with some as large as 6mm. As they matured they became hard and darker in colour. The sclerotia were produced on both diploid and haploid mycelium with the diploid sclerotia only producing diploid mycelium and never haploid. The sclerotia were able to produce mycelium even after drying for a month but fruiting bodies did not emerge from the sclerotia.[72]

3.6. Sclerotia in Bolbitiaceae

Conocybe and Pholiotina species appear to be very common to find in plant pots but despite Bolbitius species having almost as many observations on iNaturalist as Conocybe they do not seem to occur often in plant pots. There does not appear to be any documentation on sclerotia for this family besides mention of Pholiotina cyanopus (formerly Conocybe cyanopus) producing sclerotia,[52] with more attention paid to this species and it's cultivation because of its psychoactive properties. This trait however makes researching it complicated as there are a vast number of sources stating that it produces sclerotia but none appear to provide a description, photos or evidence of them. Additionally such searches routinely turn up information on the sclerotia in the Psilocybe species instead with Pholiotina or Conocybe cyanopus merely being mentioned alongside them.

iNaturalist contains few observations of this species and sclerotia are not apparent in any of them however this is not surprising as if they are anything like the sclerotia in Conocybe cf. macrospora they may not be apparent macroscopically.

Fig. 8 - Sclerotia stuck to stipe Fig. 9 - Sclerotium crush mount

A Conocybe species was found growing in an outside plant pot in late September in the United Kingdom and examination of the spores resulted in a size range of 13-21 x 8-10 µm which appears to match the description of Conocybe macrospora. When viewed at 40x magnification small clusters of irregularly shaped, roughly ellipsoidal brown structures were found (fig. 8). Isolating them from the stipe was not trivial owing to the minute size that made simply losing them easy. When specimens were placed on a slide they were barely visible to the naked eye and appeared like specks of dust on the illuminated glass and it would be easy to dismiss them as such. Crush mounts of these specimens (fig. 9) however resulted in the familiar appearance seen in crush mounts of Leucocoprinus sclerotia personally observed as well those seen in photos of sclerotia in Coprinopsis species.

Fig. 10 - Pseudoparenchymatous rind Fig. 11 - Prosenchymatous internal flesh

A more detailed look revealed the same brown, pseudoparenchymatous appearance of the rind (fig. 10) with hyaline prosenchymatous internal flesh spilling out when crushed (fig. 11). The sclerotia did not seem to offer any noticeable resistance to crushing so their hardness could not be gauged however they were so small that it is to be expected that they should not offer as much resistance as the larger sclerotia found in other species. Due to the limited number of specimens found and the extremely small size of them making manipulation awkward no measurements were attempted of the intact sclerotia with it instead being prioritised to mount them before they became lost. From the photos taken however the specimens all appeared to be under 125 µm with the smallest observed being perhaps half that size.

It will be necessary to culture this species to confirm that the sclerotia belong to it however given their proximity to the mushrooms it seems probable that they are related. In any case it may be prudent, based on this observation, to look for similar when examining Conocybe specimens. Without specifically looking for sclerotia there would scarcely be a reason to spend the time and effort to isolate and crush such objects from the base of the mushroom as in most cases such objects could be presumed to be sand, soil particles or frass. It seems probable that other species may produce similarly tiny sclerotia which simply go overlooked and only become obvious in cultures.

3.7. Other species

Cortinarius calochrous (now known as Calonarius callochrous) is ectomycorrhizal so is not going to be a species which occurs with potted plants. However the sclerotia still appear to have some similar traits as they are up to 1mm in diameter, subglobose to oblong and sometimes bi-lobed. Beneath the mycelial coating they are smooth with a white surface and a hyaline, pseudoparenchymatous interior that is described as containing subglobose, rectangular or triangular cells with a size range of 6-19 x 3.6-16 μm. In KOH they develop a pink colour. Kernaghan notes that sclerotia production by ectomycorrhizal basidiomycetes is common in Boletales but that sclerotia have also been documented in Hebeloma crustuliniforme, H. sacchariolens, Cortinarius subporphyropus (now known as Thaxterogaster subporphyropus), Cortinarius magellanicus and Cortinarius alnobetulae (Calonarius alnobetulae).[73] Given the very large size of the Cortinariaceae family and their ectomycorrhizal growth habit these are ultimately beyond the scope of this investigation and may be best explored separately.

Another mycorrhizal species which has been documented as producing sclerotia is Inocybe aeruginascens which produces abundant greenish-blue sclerotia in culture which have a diameter of 1-2mm. Sclerotia formation started 5-9 days after culturing with exudation of water droplets noted during formation. They start light green before quickly turning dark green and finally greenish-blue[74] and the sclerotia were found to contain 0.1% psilocybin by dry weight. This was documented in culture but ultimately degenerated after a few months, presumably due to the lack of a mycorrhizal symbiont.[75]

This appears to be another case where a species was studied and cultured due to the psychoactive properties whilst other species in the genus may not have been studied in such detail. There does not appear to be documentation on sclerotia in any other Inocybe species.

Willetts lists Typhula gyrans, T. intermedia, T. sclerotioides as producing sclerotia though many more species in this genus are documented as producing sclerotia including (from a cursory search) Typhula incarnata and T. ishikariensis [76], T. variabilis, T. laschii and T. japonica[77]. Typhula suecica is a species with fruiting bodies that grow from single sclerotium that are smooth, lenticular to ovoid and 600-1300 x 400-700 µm. When fresh they are reddish brown but dry to a dark reddish brown.[78]

Whilst Typhula are placed within the Agaricales order these would seem to be generally beyond the intended scope of this study. As they are plant pathogens these species have already been very well studied and documented in order to combat them and as such it does not seem necessary to collate and summarise the vast quantities of information on them here. These studies may contain some relevant information to study of sclerotia in general however. For instance the methodology of culturing sclerotia by soaking them in distilled water for 20 hours at 4°C before surface sterilising them with 70% ethanol for 5 seconds and sodium hypochlorite for 5 minutes before rinsing multiple times with sterile water and placing onto agar.[76] The resilience of sclerotia to chemicals which makes this kind of surface sterilisation possible, whilst perhaps detrimental for efforts to combat plant pathogen species in fields, may be useful for culturing them.

In Agroathelia rolfsii (formerly known as Sclerotium rolfsii) the dried sclerotia have been shown to become vulnerable to colonisation by other micro-organisms resulting in rot within 2 weeks when dried sclerotia were remoistened in soil. However drying also stimulated germination and it was hypothesised that in nature drying main be the main mechanism that promotes germination.[79] It may therefore be interesting to see whether the sclerotia in saprotrophs share traits with the sclerotia producing plant pathogen species.

Collybia tuberosa was described in 1871 by Paul Kummer as a tiny all white mushroom smaller than a penny with a stem about 1 cm tall which grows on mosses, large mushrooms, leaves, etc. No description is given of the sclerotia besides that the base is thick, hard and bulbous with a tuber.[80] William Murrill wrote that the sclerotia are bioluminescent.[81]

The species was first described and illustrated by Pierre Bulliard in 1786 as Agaricus tuberosus. Bulliard described the species as originating in the form of small seeds which grow larger and elongate ultimately leading to mushrooms growing from them. The tuber is described as solid with a taste like scorzonera, presumably referring to Pseudopodospermum hispanicum (formerly known as Scorzonera hispanica). The accompanying illustration shows the 'seeds' in multiple stages of growth with and without mushrooms and has them emerging from the gills of a decaying Agaric.[82]

Describing them as seeds truly does seem apt given the appearance of them seen in observation 131625877 by @kallampero and 178773631 by @ksanderson. This growth behaviour is seen in many of the iNaturalist observations of this species in which the sclerotia are abundantly visible however Collybia cookei and C. racemosa are also documented as producing similar sclerotia and Komorowksa notes that distinguishing these species is troublesome even via microscopy. Identification is aided by examining the cortext of the sclerotia with surface material of fresh or dry sclerotia crushed in 3% KOH or NaOH and phloxine. The surface texture of each species is distinct with C. tuberosa having elongate hyphae on the surface of the sclerotia whilst in C. cookei they are round and in C. racemosa they are angular. C. cirrhata does not produce sclerotia.[83]

C. racemosa is now known as Dendrocollybia racemosa and sclerotia are likewise readily seen in iNaturalist observations of this species. There are no observations on iNaturalist from plant pots for any of these species or anything else in the Collybia genus. This is not surprising given their tendency to grow from decaying mushrooms though possibly the sclerotia of these species provide some explanation for the early descriptions of mushrooms arising from sclerotia on the gills of decaying Agarics in bark beds. The similar looking (and similarly named) Lactocollybia genus does have several observations from plant pots, specifically from potted Orchids. However these are not closely related with Collybia placed in Tricholomatineae and Lactocollybia in Marasmiineae.

Nidulariaceae are not uncommon to find in plant pots and sometimes appear alongside L. birnbaumii. Macroscopically their peridioles are somewhat similar in appearance to sclerotia but of course they contain spores whereas sclerotia do not. iNaturalist observation 150248388 by @komille277 of a Mycocalia species shows a similarly pseudoparenchymatous surface texture when the peridioles are viewed at 1000x magnification. However unlike the sclerotia they appear to readily take up a blue stain. The peridioles of many Nidulariaceae have a brown exterior similar in appearance to sclerotia though whether this is also due to the presence of melanin does not appear to have been discussed.

It has been hypothesised that the Nidulariaceae may engage in 'seed mimicry' with their peridioles appearing like seed to foraging birds who may then eat them resulting in spores being distributed further afield than could be achieved just from raindrops splashing the peridioles out of the cup.[84] This has not been demonstrated in nature but one study demonstrated that canaries would eat them only if mixed with other food and undamaged spores were able to pass through the digestive system.[85]

There is an association regarded between many bird and fungi species with spore distribution via bird faeces proposed as a dispersal mechanism as well as an explanation for why New Zealand appears to have so many brightly coloured gasteroid fungi and truffles. Many of these species resemble berries with their red, blue or purple colouration and the region has many ground dwelling birds[86]

An association between birds and sclerotia however does not seem to have been considered, perhaps because sclerotia are generally regarded as large subterranean structures with the small, seed like sclerotia of Leucocoprinus and Coprinoids being less well known. Given the seedlike appearance of the tiny sclerotia found in these species it seems worth considering whether they can also be spread via birds.

4. Conclusion

Documentation of sclerotia in the Agaricales appears lacking and it seems probable that if more species are examined with a specific view to looking for sclerotia then this trait will be found in other species. As is seen with the sclerotia in Leucocoprinus, Coprinopsis and Conocybe these structures can be so small as to go unregarded in nature as they are not readily distinguished from pieces of debris, dust, sand, soil, eggs or insect frass unless the observer is deliberately looking for them. These tiny sclerotia do not seem to be well known and so most observers are not likely to notice them and in the case of the smallest sclerotia observers without access to a microscope are not going to be able to correctly diagnose the structures as sclerotia. It is only with a crush mount or dissection that their true nature is revealed and dissection is not trivial owing to the size and hardness of the sclerotia.

Realistically the only way to observe and study these tiny sclerotia seems to be to culture them. Whilst they are hard to find in nature they can be abundantly apparent on agar or other substrates such as brown rice. Additionally these nutritionally rich substrates generally appear to result in the production of vastly more sclerotia than may be found in nature. As sclerotia have shown some resilience to contamination and as their production was only observed in conjunction with some manner of contaminate in a number of studies it is possible, in some species at least, that sclerotia production might be unreliable in a sterile substrate. This will require further examination but my own initial studies do seem to suggest that sclerotia growth in Leucocoprinus species may be prompted by (though not reliant upon) the presence of contaminants and that the sclerotia seem to afford some protection against them. Subsequently if a species is cultured on agar or substrate in a sterile environment and no sclerotia are produced this may not necessarily guarantee that the species is incapable of producing them.

It is my hope that by studying the sclerotia produced by Leucocoprinus species in culture their purpose in nature may become clearer. To that end I intend to document the sclerotia of some of the most commonly observed species from plant pots and explore their possible role as a distribution mechanism for the fungus in their natural environment. It is my expectation that the presence of sclerotia as well as the specific traits of them may explain why some species are so common in plant pots and this in turn may help understand their behaviour in the wild.


  • [1] Smith, Matthew E.; Henkel, Terry W.; Rollins, Jeffrey A. (January 2014). "How many fungi make sclerotia?". Fungal Ecology. 13, pg. 6.
  • [2] Matsuzawa, Tetsuhiro; Horie, Yoshikazu; Yaguchi, Takashi; Sakamoto, Yumiko; Fukiharu, Toshimitu. (2011). "Economic damage to cyclamen growth by sclerotia of Leucocoprinus birnbaumii". Japanese Journal of Mycology. 52 (1): jjom.H22–05.
  • [3] Mattirolo, Oreste. (1918). "Sul Ciclo di Sviluppo di due Specie Scleroziate del Gen. Lepiota Fr. e Sulle Loro Affini". Memorie della R. Accademia dei Lincei, Serie Quinta, Volume XII, Fascicolo XI, pp. 537-572.
  • [4] Hennings, P. (1898). " Die in den Gewächshäusern des Berliner botanischen Gartens beobachteten". p. 143 (p. 35 in the PDF).
  • [5] Nees von Esenbeck, Christian Gottfried Daniel. (1817). "Das System der Pilze und Schwämme".
  • [6] Fries, Elias Magnus. (1822). "Systema Mycologicum". 2, p. 253.
  • [7] Westendorp, Gérard Daniel. (1863). "Notice sur quelques espèces nouvelles ou inédites pour la flore belge". Bulletins de la Société Royale de Botanique de Belgique 2 (2), p. 246.
  • [8] Kickx, Jean. (1867). "Flore cryptogamique des Flandres. Oeuvre posthume de Jean Kickx par Jean Jacques Kickx". p. 470.
  • [9] Fayod, Victor. (1889). "Histoire Naturelle des Agaricinés". Annales des sciences naturelles Botanique. 7 (9), p.210.
  • [10] Adalbert Ricken. (1915). "Die Blätterpilze". Band 1, p.320 (p. 350 in the PDF).
  • [11] Cejp, Karel. (1948). "Dva tropičtí zástupci bělohnojniků v našich sklenicích". Česká Mykologie. 2 (3), p. 78.
  • [12] Persoon, Christiaan Hendrik. (1801). "Synopsis methodica fungorum". pars 1-2, p. 123.
  • [13] Fries, Elias Magnus. (1822). "Systema Mycologicum". 2, p. 266.
  • [14] Schumacher, Heinrich Christian Friedrich. (1803). "Enumeratio Plantarum, in Partibus Sællandiae Septentrionalis et Orientalis Crescentium". 2, p. 187.
  • [15] Hornemann, Jens Wilken. (1806-1810). "Floræ Danicæ Iconum". Achter band, tab 1320 (MCCCXX), (page 70 of the PDF).
  • [16] Mcquire, Will; Conway, Jess. (2019). "Nature's true colours". kew.org
  • [17] Corda, August Karl Joseph. (1838). "Icones fungorum hucusque cognitorum tomus II." p. 30 & Tab XIII (37 and 56 of the PDF).
  • [18] Ferraris, Teodoro. (1910). "Flora Italica cryptogama. Pars I: Fungi. Hyphales: Tuberculariaceae - Stilbaceae / Auctore T. Ferraris. Fascicolo N. 6". p. 58 (60 in the PDF).
  • [19] Corda, August Karl Joseph. (1839). "Icones fungorum hucusque cognitorum tomus III." p. 48 (56 in the PDF).
  • [20] Saccardo, Domenico. (1899). "Supplemento micologico alla "Flora veneta crittogamica". Parte I. -- I Funghi di Giacomo Bizzozero". p. 100.
  • [21] Nennmann, Holger. (2021). "Orchids deseases: Weeds & funghi in the substrate".
  • [22] Schnizlein, Adalbert. (1851). "Deutschlands flora in abbildungen nach der natur". Abt.3, 31-31, pp. 1-3.
  • [23] Rabenhorst, Ludwig. (1844). "Deutschlands Kryptogamen-Flora oder Handbuch zur Bestimmung der kryptogamischen Gewächse Deutschlands, der Schweiz, des Lombardisch-Venetianischen Königreichs und Istriens." 1, p. 572 (602 in the digital version).
  • [24] Migliozzi, Vincenzo. (2020). "Due interessanti Leucocoprinus bianchi.Leucocoprines medioflavus var. niveus var.nov. e Leucocoprinus straminellus var. albus comb. nov."
  • [25] Noordeloos, M.E.; Kuyper, TH.W.; Vellinga, E.C.; (2001). "Flora Agaricina Neerlandica Critical monographs on families of agarics and boleti occurring in the Netherlands Vol. 5." pp.80-82.
  • [26] Reid, Derek A. (1989). "Notes on some Leucocoprinoid fungi from Britain". Mycological Research. 93 (4), p. 418.
  • [27] Boudier, Émile. (1905). "Icones mycologicæ, ou Iconographie des champignons de France principalement Discomycetes". Vol. 1, Pl. 18.
  • [28] Boudier, Émile. (1905). "Icones mycologicæ, ou Iconographie des champignons de France principalement Discomycetes". Vol. 4, pp. 9-10.
  • [29] Hongo, Tsuguo. (1953). "Larger fungi of the provinces of Omi and Yamashiro".
    Journal of Japanese Botany, Vol. 28, No. 3, pp. 70-72.
  • [30] Bartsch, Andrea; Bross, Monika; Spiteller, Peter; Spiteller, Michael; Steglich, Wolfgang. (2005). "Birnbaumin A and B: Two Unusual 1-Hydroxyindole Pigments from the "Flower Pot Parasol" Leucocoprinus birnbaumii". Angewandte Chemie International Edition. 44 (19), pp. 2957–2959.
  • [31] Fries, Elias. (1829). "Systema mycologicum". 3, pp. 66-67.
  • [32] Sowerby, James. (1803). "Coloured Figures of English Fungi Or Mushrooms". Vol. III, p. 12 and tab. CCLXX.
  • [33] Ingleby, K.; Mason, P.; Last, F. T.; Fleming, L. (1990). "Identification of Ectomycorrhizas." pp. 71-74.
  • [34] Boudier, MM.; Patouillard, Narcisse Théophile. (1900). "Note sur deux Champignons hypogés". Bulletin de la Société mycologique de France. t. 16, pp. 141–144.
  • [35] Patoulliard, Narcisse Théophile. (1891). "Remarques sur L'organisation de Quelques champignons exotiques". Bulletin de la Société mycologique de France. t. 7, pp. 45-47.
  • [36] van Bambeke, Ch. (1900). "Le Coccobotrys xylophilus (Fr.) Boud. et Pat. (=Cenoccoum xylophilum Fr.) est le Mycélium du Lepiota meleagris (Sow.) Sacc". Bulletin de la Société royale de botanique de Belgique. t. 39, pp. 81–88.
  • [37] Stalpers et al. (2021). "Competing sexual-asexual generic names in Agaricomycotina (Basidiomycota) with recommendations for use". p. 16.
  • [38] Baglietto Francesco. (1886). "Funghi della liguria". Nuovo Giornale Botanico Italiano, Vol. 18, p. 235.
  • [39] Warcup, J.H.; Talbot, P.H.B. (1962). "Ecology and identity of mycelia isolated from soil". Transactions of the British Mycological Society. 45 (4), pp. 495–518.
  • [40] Willetts, H. J. (1971). "The survival of fungal sclerotia under adverse environmental conditions". Biological Reviews, Vol. 46, Iss. 3, pp. 387-407.
  • [41] Volz, Paul. A.; Niederpruem, Donald J. (1970). "The Sclerotia of Coprinus lagopus". Archiv für Mikrobiologie, Vol. 70, pp. 369-377.
  • [42] Waters, H.; Butler, R. D.; Moore, D. (1975). "Structure of aerial and submerged sclerotia of Coprinus lagopus". New Phytologist, Vol. 74, pp. 199-205.
  • [43] Moore, David. (2022). "Wild-type strains of Coprinus lagopus unable to produce sclerotia".
  • [44] Nagy, Laszlo G.; Desjardin, Dennis E.; Vágvölgyi, Csaba; Kemp, Roger. (2012). "Phylogenetic analyses of Coprinopsis sections Lanatuli and Atramentarii identify multiple species within morphologically defined taxa". Mycologia, Vol. 105 (1), pp. 112-124.
  • [45] Watanabe, Tsuneo; Tagawa, Masahiro; Tamaki, Hideyuki; Hanada, Satoshi. (2011). "Coprinopsis cinerea from rice husks forming sclerotia in agar culture". Mycoscience, Vol. 52, Issue 2, pp. 152-156.
  • [46] Nordberg H.; Cantor M.; Dusheyko S.; Hua S.; Poliakov A.; Shabalov I.; Smirnova T.; Grigoriev IV.; Dubchak I. "Coprinopsis sclerotiger v1.0". MycoCosm website, The Genome Portal of the Department of Energy Joint Genome Institute.
  • [47] Badalyan, Susanna M.; Navarro-González, Mónica; Kües, Ursula. (2011). "Taxo­nomic significance of anamorphic characteristics in the life cycle of coprinoid mushrooms". Conference: ICMBMP7, Vol. 1, pp. 140-152.
  • [48] Traquair, James A.; Gaudet, Denis A.; Kokko, Eric G. (1987). "Ultrastructure and influences of temperature on the in vitro production of Coprinus psychromorbidus sclerotia". Canadian Journal of Botany, Vol.65, No. 1, pp. 124-130.
  • [49] Uljé, C. B.; Noordeloos, M. E. (1997). "Studies in Coprinus IV - Coprinus section Coprinus. Subdivision and revision of subsection Alachuani." Persoonia, Vol. 16, part 3, pp. 283 - 285.
  • [50] Walker, J.; Moore, K. (1974). "Coprinus stercorarius as an industrial contaminant". Transactions of the British Mycological Society, Vol. 63, Issue 3, pp. 449-455.
  • [51] Choi, Hyoung T. (1987). "Formation of Sclerotia in Liquid Cultures of Coprinus congregatus and Their Phenoloxidase Isozymes". Mycologia, Vol. 79, Issue 2, pp. 166-172.
  • [52] Stamets, Paul. (1996). "Psilocybin Mushrooms of the World: An Identification Guide". p. 24.
  • [53] Heim, Roger; Brack, Arthur; Kobel, Hans; Hofmann, Albert; Cailleux, Roger. (1958). "Déterminisme de la formation des carpophores et des sclérotes dans la culture du Psilocybe mexicana Heim, Agaric hallucinogène du Mexique, et mise en évidence de la psilocybine et de la psilocine." Comptes rendus hebdomadaires des séances de l'Académie des sciences, T. 246 (1), pp. 1346-1351.
  • [54] Pellegrini, Manuela; Rotolo, Maria Concetta; Marchei, Emilia; Pacifici, Roberta; Saggio, Francesco; Pichini, Simona. (2012). "Magic truffles or Philosopher’s stones: a legal way to sell psilocybin?" Drug Testing and Analysis, Vol. 5, Iss. 3, pp. 182-185.
  • [55] Redhead, Scott A.; Kroeger, Paul. (1987). "A sclerotium-producing Hypholoma from British Columbia". Mycotaxon Vol. 29, pp. 457-465.
  • [56] Walleyn, Ruben. (1998). "Twee Zeldzame Agaricales Gevonden in België". Sterbeeckia, Vol. 18, pp. 11-12.
  • [57] Karsten, P. A. (1904). "Fungi novi, pauci exceptis, in Sibiria a clarissimo O. A. F. Loennbohm collecti." Öfversigt af Finska vetenskaps-societetens förhandlingar, Vol. 46, p. 2.
  • [58] Derboven, Pascal; Fraiture, André. (2009). "Hypholoma tuberosum, un hypholome qui produit des sclérotes". Revue du Cercle de Mycologie de Bruxelles, Vol.9, pp. 43-51.
  • [59] Priest, M. J.; Simpson, J. A. (1992). "Hypholoma tuberosum in Australia". The Mycologist, Vol. 6 (1), pp. 11-12.
  • [60] Fox, Frances M. (1986). "Ultrastructure and infectivity of sclerotium-like bodies of the ectomycorrhizal fungus Hebeloma sacchariolens, on birch (Betula spp.)". Transactions of the British Mycological Society, Vol. 87, Iss. 3, pp. 359-369.
  • [61] Bonito, Gregory M.; Healy, Rosanne; Nowak, Michael; Guerrero, Gonzalo Geuvara; et al. (2013). "Historical Biogeography and Diversification of Truffles in the Tuberaceae and Their Newly Identified Southern Hemisphere Sister Lineage." PLoS ONE, Vol. 8, Iss. 1, e52765.
  • [62] Hennings, Paul. (1903). "Ein Sklerotien-Blätterpilz, Naucoria tuberosa P. Henn. n. sp. ad inter." Hedwigia, Vol. 42, pp. 310-312.
  • [63] Fries, Elias Magnus. (1821). "Systema mycologicum." Vol. 1, p. 265.
  • [64] Beardslee, H. C. (1918). "Stropharia Tuberosa". Mycological Notes, No. 53, pp. 751-753.
  • [65] Lloyd, C. G.; Boutlou. (1917). "A Naucoria from a sclerotium". Mycological Notes, No. 51, pp. 722-723.
  • [66] Redhead, Scott A. (2014). "Nomenclatural novelties". Index Fungorum no. 158.
  • [67] Seger, C.; Gallego, JC.; Takiuchi E.; Cortez VG. (2017). "Taxonomy of the south Brazilian species of Protostropharia (Strophariaceae, Agaricales)". Mycosphere, Vol. 8 (8), pp. 1044-1053.
  • [68] Clémençon, Heinz; Roffler, Urs. (2003). "The pseudosclerotia of the agaric Stropharia luteonitens". Mycological Progress, Vol. 2 (3), pp. 235-238.
  • [69] Lopez-Real, J. M.; Swift, M. J. (1977). "Formation of pseudosclerotia (“zone lines”) in wood decayed by Armillaria mellea and Stereum hirsutum. I. Morphological aspects." Transactions of the British Mycological Society, Vol. 64, pp. 465-471.
  • [70] Lam, Ka-Lung; Kaiwei, Si; Xiyang, Wu; Shuze, Tang; Xiaohui, Sun; Kwan, Hoi-Shan; Cheung, Chi-Keung Peter. (2018). "The diploid genome of the only sclerotia-forming wild-type species in the genus Pleurotus - Pleurotus tuber-regium - provides insights into the mechanism of its biomass conversion from lignocellulose substrates". Journal of Biotechnology, Vol. 283.
  • [71] Fasidi, I.O.; Ekuere, U.U. (1993). "Studies on Pleurotus tuber-regium (Fries) Singer: cultivation, proximate composition and mineral contents of sclerotia". Food Chemistry Vol. 48 (3), pp. 255-258.
  • [72] Brodie, Harold J. (1935). "The heterothallism of Panaeolus subbalteatus Berk., a sclerotium-producing agaric". Canadian Journal of Research, Vol. 12, No. 5, pp. 657-660.
  • [73] Kernaghan, G. (2001). "Ectomycorrhizal fungi at tree line in the nCanadian Rockies II. Identification of ectomycorrhizae by anatomy and PCR". Mycorrhiza, Vol. 10 (5), pp.217-229.
  • [74] Gartz, Jochen. (1986). "Psilocybin in Mycelkulturen von Inocybe aeruginascens". Biochemie und Physiologie der Pflanzen, Vo. 181, Iss. 7, pp. 511-517.
  • [75] Gartz, Jochen. (1992). "New aspects of the occurrence, chemistry and cultivation of european hallucinogenic mushrooms". Supplemento agli Annali dei Musei Civici di Rovereto Sezione Archeologica, Storia e Scienze Naturali, Vol. 8.
  • [76] Matsumoto, N.; Tajimi, A. (1985). "Field survival of sclerotia of Typhula incarnata and of T. ishikariensis biotype A". Canadian Journal of Botany, Vol. 63 (6), pp. 1126-1128.
  • [77] Ikeda, Sachiko; Hoshino, Tamotsu; Matsumoto; Naoyuki; Kondo, Norio. (2015). "Taxonomic reappraisal of Typhula variabilis, Typhula laschii, Typhula intermedia, and Typhula japonica". Mycoscience, Vol. 56 (5), pp. 549-559.
  • [78] Olariaga, Ibai; Corriol, Gilles; Salcedo, Isabel; Hansen, Karen. (2016). "A new species of Typhula with sigmoid spores: Typhula suecica". Karstenia, Vol. 56, Iss. 1-2, pp. 27-38.
  • [79] Smith, A. M. (1972). "Drying and wetting sclerotia promotes biological control of Sclerotium rolfsii Sacc". Soil Biology and Biochemistry, Vol. 4, Iss. 2, pp. 119-120.
  • [80] Kummer, Paul. (1871). "Der Führer in die Pilzkunde". pp. 116.
  • [81] Murrill, William A. (1915). "Luminescence in the Fungi". Mycologia, Vol. 7, pp. 131-133.
  • [82] Bulliard, Pierre. (1783-1786). "Herbier de la France". Vols. 4-6, fasc. 37-72, pl. 256 (p. 112 in the PDF).
  • [83] Komorowksa, Halina. (2000). "A new diagnostic character for the genus Collybia (Agaricales)". Mycotaxon, Vol. 75, pp. 343-346.
  • [84] Reichholf, Josef H.; Lohmeyer, Till R. (2012). "Regentropfen oder Samen-Mimikry? Evolutionsbiologische Gedanken über Verbreitungsstrategien der Teuerlinge". Mycologia Bavarica, Band 13, pp. 1-7.
  • [85] Sarasini M, Pina G. (1995). Nidulariaceae; prima parte. Ciclo vitale e caratteri generali: il genere Crucibulum. Rivista di Micologia, Vol. 38, pp. 237–252.
  • [86] Elliott, Todd F.; Jusino, Michelle A.; Trappe, James M.; Lepp, Heino; Ballard, Guy-Anthony; Bruhl, Jeremy J.; Vernes, Karl. (2019). "A global review of the ecological significance of symbiotic associations between birds and fungi". Fungal Diversity, Vol. 98 (02).
  • Publicado el 26 de octubre de 2023 00:05 por mycomutant mycomutant | 6 comentarios | Deja un comentario

    26 de septiembre de 2023

    Leucocoprinus cretaceus temperature assessment

    This is a review of observations of Leucocoprinus cretaceus with the temperatures for the location taken from www.timeanddate.com. The purpose is to assess seasonality in different locations and gauge the temperature tolerance of this species in regards to fruiting requirements and so this table is arranged by the month of observation. Only observations of mushrooms fruiting outside have been included. Observations from plant pots are collected in the plant pot mushrooms project and some observations of Leucocoprinus cretaceus fruiting inside buildings and structures have also been collected so these indoor observations could be separately assessed easily. In instances where the mushrooms are noted as growing from a compost pile in the description this is included in the location data since such an environment could increase local temperatures.

    Observations have been manually reviewed and only included if I am satisfied that the species pictured is indeed L. cretaceus and not any of the possible lookalikes. As there are many observations for this species this table is not going to attempt to collect data for all of them but rather represents a random sample from a variety of locations. It was convenient to focus on locations with many observations over a wide period of time in order to expedite data entry.

    Place names given are for the weather results rather than the observation location. In most cases they are the same but where observations are from small towns or wilderness locations situated right beside large population centres the name of the larger population centre may have been used since looking up small locations does not always result in finding temperature records. The data for smaller locations on timeanddate will be taken from stations in larger locations nearby anyway and whilst small town nams are generally searchable in America and Europe they often turned up no results in India and South America.

    In some cases timeanddate is entirely missing weather data for some locations during some periods and so otherwise good observations have been excluded based on this lack of data. Where weather data is available but some is missing for that day a ? is included beside the temperature. For instance a low temperature of '7?' indicates that the night time temperatures for this location were missing and hence the lowest temperature recorded that day may have been lower but the high temperature can be presumed to be accurate since the rest of the data was present.

    The lowest and highest number given are the result of reading the summary provided for that day which on timeanddate is broken into 4 time slots: 00:00, 06:00, 12:00, 18:00 with a low and high given for each period. The low and high given here represent the lowest and highest of these 8 figures given except in cases were a sudden, abnormal change in temperature is noted after the time given for the observation. ie. for an observation made at midday when the high was 28 and the low was 16 but a sudden drop occurred to 8 (far colder than any of the days prior) by 18:00 then this later temperature is excluded and the earlier low of 16 is used. A case like this is unusual and the low temperatures are usually representative of the early morning or overnight low before the mushroom was observed. Otherwise the time of the observation is not taken into account and the high or low used may represent a temperature after the observation was made unless, at a glance, this was obviously extreme compared to the days before. More accurate hour by hour temperatures are available for most entries on timeanddate though it would require more time spent per observation to look this up and exclude information from after the time of the observation.

    The link to the timeanddate page is included for each entry in order that more detailed temperatures or weather data can be found quickly. ie. if an additional assessment were to be carried out at a later date to look for rain or storms prior to the observation. Assessing the temperature on the day the mushrooms were observed may not be the most reliable method of evaluating temperature requirements as it may be preferable to assess the days before the mushrooms were observed. This could provide a better idea of the temperatures needed to trigger growth and avoid the mushroom aborting however such an assessment would have to take into account the maturity of the mushrooms and their quality, ie. if aborting or growing poorly and so would be more complex and less reliable. Due to the tedious nature of copy pasting data into multiple fields it is possible that some errors may exist in this data however as the obervation number, username and location are included it provides some redundancy for fixing this. ie. it is possible that one field might not have been updated but unlikely all have not.

    North America

    Date Location Low (°C) High (°C) Observation User Link
    Jan 2, 2023 Honolulu, Hawaii, US 20 26 145740596 @kairigney Link
    Jan 4, 2020 Kauai County, Hawaii, USA 23 25 37332502 @acanthusmxmli Link
    Feb 23, 2012 Corpus Christi, Texas, US 18 27 1022519 @fmoretzsohn Link
    Apr 18, 2023 Miami, Florida, US 19 29 155526027 @camille564 Link
    Apr 19, 2015 Mission, Texas, US 21 33 146471953 @mikephelps Link
    Apr 21, 2023 San Antonio, Texas, US 17 28 155946467 @bobbie50 Link
    May 3, 2019 Hawaii County, Hawaii, US 21 27 37863770 @johnfraser1 Link
    May 15, 2019 Captain Cook, Hawaii, US 24 28 25248992 @johnfraser1 Link
    May 20, 2023 San Marcos, Texas, US 20 28 162744708 @ironchefphil Link
    May 23, 2020 Xalapa, Veracruz, Mexico 26? 33 47019848 @richardortem Link
    Jun 4, 2021 Garden Ridge, Texas, US 19 27 81603760 @cyndie42 Link
    Jun 7, 2021 Xalapa, Veracruz, Mexico 26 35 81985228 @xxcarlosxx Link
    Jun 11, 2022 Xalapa, Veracruz, Mexico 25 32 123684424 @marco_bautista99 Link
    Jun 21, 2021 José Cardel, Veracruz, Mexico 24? 25? 83968202 @vkbiol Link
    Jun 30, 2021 Santiago de Querétaro, Mexico 14 23 85152020 @branrivera Link
    Jul 4, 2023 San Antonio, Texas, US 26 36 171115544 @teristwin Link
    Jul 14, 2023 Detroit, Michigan, US 19 29 173054834 @mossmuncher Link
    Aug 1, 2023 Xalapa, Veracruz, Mexico 25 32 176204120 @narinat Link
    Aug 3, 2023 Bowling Green, Kentucky, US 23 24 129269871 @charitys9 Link
    Aug 3, 2023 Túxpam de Rodríguez Cano, Veracruz, Mexico 16? 22 176600250 @jaime_medrano Link
    Aug 7, 2023 Veracruz, Veracruz, Mexico 24 34 177185957 @tamar_way Link
    Aug 8, 2020 Ottawa, Ontario, Canada (compost pile) 14 29 56020699 @randylast Link
    Aug 9, 2022 Ann Arbor, Michigan, US 18 24 130143958 @carly_rita Link
    Aug 10, 2020 Ottawa, Ontario, Canada (compost pile) 16 29 56042519 @kevinwallace Link
    Aug 12, 2020 Haʻikū, Hawaii, US 24 33 56388103 @mscharer Link
    Aug 16, 2021 Eugene, Oregon, US (compost heap) 14 31 91433273 @oregon_af Link
    Aug 25, 2023 Norfolk County, Ontario, Canada (compost/manure pile) 18 23 180171185 @dan_macneal Link
    Aug 28, 2022 San Antonio, Texas, US 26 35 81603760 @kimkennedysa Link
    Sep 3, 2020 Pickering, Ontario, Canada (manure pile) 17 25 58482142 @foragergirl Link
    Sep 10, 2022 San Antonio, Texas, US 24 34 134417572 @kruegerk12 Link
    Sep 12, 2020 Altotonga, Veracruz, Mexico 23? 30 60585353 @sandra880 Link
    Sep 13, 2020 Allegheny County, Pennsylvania, US 19 24 59455121 @bobbybo123 Link
    Sep 17, 2018 San Antonio, Texas, US 21 32 17052957 @pambenavides Link
    Sep 17, 2022 Kailua, Hawaii, US 20 33 135510184 @richfisc Link
    Sep 18, 2018 Grand Rapids, Michigan, US 18 27 16670390 @majoraim Link
    Sep 19, 2020 San Luis Potosi, Mexico 13 19 60351002 @andreafigueroa Link
    Sep 20, 2022 Cuetzalan, Puebla, Mexico 13? 23 136310748 @magali70 Link
    Sep 22, 2018 Tillamook County, Oregon, US 9 21 16822823 @richtehan Link
    Sep 22, 2023 Chicago, Illinois, USA 19 26 184455962 @michael-r Link
    Sep 27, 2020 Xalapa, Veracruz, Mexico 23? 33 60980556 @erick19 Link
    Sep 30, 2018 San Antonio, Texas, US 22 28 17852728 @philycheez Link
    Oct 7, 2021 Tamworth, Ontario, Canada (plant pot, outside) 14 21 97446308 @ruffian Link
    Oct 17, 2019 Actopan, Veracruz, Mexico 24 28 34744294 @tereso30 Link
    Oct 27, 2020 Kaneohe, Hawaii, US 23 27 156796113 @cacaruso Link
    Nov 1, 2017 Berkeley, California, US 8 19 8654385 @rraman Link
    Nov 9, 2022 Corpus Christi, Texas, US 21 29 141563147 @janeweeden Link
    Nov 11, 2022 Stagecoach, Texas, US 16 28 141719758 @oceanicwilderness Link
    Nov 18, 2017 Austin, Texas, US 20 28 8949872 @hydaticus Link
    Nov 27, 2022 Miami, Florida, US 24 31 143035753 @eduardo_alizo Link
    Dec 5, 2022 Mission, Texas, US 22 28 143725326 @ajwhitlock Link
    Dec 6, 2022 Mission, Texas, US 20 29 145446072 @krcdp9 Link
    Dec 8, 2022 Madero, Texas, US 21 29 143970967 @candi12 Link
    Dec 9, 2021 Honolulu, Hawaii, US 22 28 102785824 @shroomsday Link
    Dec 9, 2022 San Marcos, Texas, US 20 28 144034957 @emiliowanders Link
    Dec 17, 2022 New Braunfels, Texas, US 7? 18 150280019 @haakonskjonberg Link
    Dec 19, 2022 Honolulu, Hawaii, US 19 24 156796050 @cacaruso Link

    South America

    Date Location Low (°C) High (°C) Observation User Link
    Jan 4, 2015 Alta Floresta, Mato Grosso, Brazil 26? 32 164812032 @suse100 Link
    Jan 13, 2019 Rio Branco, Acre, Brazil 22 29 21486037 @chirley_silva Link
    Jan 19, 2020 Manú, Madre de Dios, Peru 6 21 179607697 @blazeclaw Link
    Jan 28, 2023 Guayaquil, Ecuador 25 31 149040936 @benjaminnavas Link
    Feb 1, 2023 Montevideo, Uruguay 20 28 147827328 @laacolito Link
    Feb 5, 2023 Leticia, Colombia 23 27 149907907 @giulioz Link
    Feb 26, 2023 Victoria, Entre Rios, Argentina 16 32 149764778 @estefi3 Link
    Mar 15, 2023 Chiclayo, Lambayeque, Peru 25 31 151278526 @lourdes_zune_2002 Link
    Mar 22, 2023 Mendoza, Argentina 18 27 151919147 @guille Link
    Mar 27, 2023 Porto Estrela, Mato Grosso, Brazil 24 34 153312962 @igorazevedo Link
    Mar 28, 2021 Villa El Salvador, Lima, Peru 19 25 72305886 @ruthgo Link
    Apr 2, 2022 Campo Grande, Mato Grosso Do Sul, Brazil 18 26 110185571 @ninawenoli Link
    Apr 8, 2020 Senador Guiomard, Acre, Brazil 22 27 41863874 @isaac_oliveira Link
    Apr 14, 2020 Senador Guiomard, Acre, Brazil 23 32 51425244 @geysesouza Link
    Apr 18, 2020 Puerto Ayora, Ecuador 20 33 42520528 @isaschreyer Link
    Apr 23, 2023 La Leonesa, Chaco, Argentina 13 28 156737873 @mirian15 Link
    Apr 24 2012 Santa Cruz de la Sierra, Bolivia 21 28 7006995 @kallampero Link
    May 8, 2022 Campina Grande do Sul, Paraná, Brazil 9 18 148608600 @reisab Link
    May 23, 2023 Buenos Aires, Argentina 17 21 163874217 @alesitoide Link
    Mar 24, 2023 João Pessoa, Paraíba, Brazil 24 29 152435121 @sam_afm Link
    May 27, 2020 Bento Fernandes, Rio Grande do Norte, Brazil 24 31 169065319 @daygo_nf Link
    Jun 3, 2017 João Pessoa, Paraíba, Brazil 23 28 33972354 @aerian Link
    Jun 13, 2023 Cantón Aguarico, Ecuador (ant nest?) 7 14? 169876009 @azalia_criollo Link
    Jun 14, 2023 Montevideo, Uruguay -2 14 167425167 @erincita01 Link
    Jul 8, 2017 Puerto Ayora, Ecuador 20 28 32260977 @wcabrera3 Link
    Oct 16 2018 Rio Branco, Acre, Brazil 24 34 17609579 @edson_guilherme Link
    Oct 22, 2021 Boca do Acre, Amazonas, Brazil 25 33 99546211 @douglas_menezes Link
    Oct 23, 2021 Rio Branco, Acre, Brazil 25 35 99632943 @chirley_silva Link
    Oct 24, 2021 Alta Floresta, Mato Grosso, Brazil 22? 28? 99226354 @reicielly Link
    Oct 24, 2021 Alta Floresta, Mato Grosso, Brazil 22? 28? 99277354 @geovanna_rodrigues Link
    Oct 30, 2021 Rio Branco, Acre, Brazil 22 35 99787058 @cafebio Link
    Nov 17, 2018 Rio Branco, Acre, Brazil 24 32 69376855 @chirley_silva Link
    Nov 17, 2019 Senador Guiomard, Acre, Brazil 22 32 37354913 @martin-acosta Link
    Nov 22, 2021 Rio Branco, Acre, Brazil 23 30 101731084 @wendelcastro Link


    Date Location Low (°C) High (°C) Observation User Link
    Jun 21, 2023 Larissa, Greece 17 32 168832188 @grzegorz_jarosiewicz Link
    Sep 10, 2022 Kraljevo, Serbia 17 27 144309185 @brankokv Link
    Sep 11, 2023 Maiorca, Portugal 17 23 182994675 @maricel-patino Link
    Sep 14, 2023 Murcia, Spain 25 30 183197699 @jorge_plaza Link
    Sep 17, 2022 Caldas da Rainha, Portugal 19 25 139008480 @jonnyvanbatman Link
    Sep 19, 2023 Callosa d'En Sarrià, Alicante, Spain 22 26 184364369 @nibor_ Link
    Sep 23, 2023 Poggio-Mezzana, Haute-Corse, France 17 26 184493855 @papilou2250 Link
    Oct 2, 2022 Navata, Girona, España 10 28 138591244 @mammal Link
    Nov 2, 2019 Aveiro, Portugal 15 18 35195370 @mariarp93 Link

    Australia and New Zealand

    Date Location Low (°C) High (°C) Observation User Link
    Jan 3, 2022 Smithfield Conservation Park, Queensland, Australia 24 34 104234772 @mmpro Link
    Jan 6, 2021 Townsville, Queensland, Australia 24 29 68323133 @drongo Link
    Jan 7, 2022 Upper Mount Gravatt, Queensland, Australia 25 27 104511084 @misfits_vintage Link
    Jan 9, 2020 Cairns, Queensland, Australia 24 31 37451381 @kerrycoleman Link
    Jan 10, 2020 Bloomfield, Queensland, Australia 24 32 37455157 @oriam Link
    Jan 10, 2022 Larapinta, Queensland, Australia 22 28 104687663 @fjadec Link
    Jan 17, 2021 Woodbury, Queensland, Australia 24 33 68176921 @hughianni Link
    Jan 23, 2022 Mount Nebo, Queensland, Australia 19 27 105417311 @barbara1112 Link
    Jan 25, 2020 Eerwah Vale, Queensland, Australia 24 29 37979669 @carolynstewart Link
    Jan 27, 2022 Cairns, Queensland, Australia 25 31 105634680 @upollo Link
    Feb 3, 2022 Mount Sheridan, Queensland, Australia 25 34 106143281 @rhinolophus Link
    Feb 4, 2022 Eungella, Queensland, Australia 23 28 106115817 @beaniana08 Link
    Feb 8, 2020 Cape Hillsborough National Park, Queensland, Australia 24 32 38402616 @debinmackay Link
    Feb 15, 2020 Rooty Hill, New South Wales, Australia 19 26 38662185 @gypsygirl75 Link
    Feb 15, 2020 Lane Cove, New South Wales, Australia 19 26 74121660 @marcalet Link
    Feb 26, 2021 Remuera, Auckland, New Zealand 15 25 70214417 @melissa29 Link
    Feb 29, 2020 Gargett, Queensland, Australia 24 31 39335961 @draaron Link
    Mar 2, 2019 Perth, Western Australia, Australia 11 26 20875695 @karolina Link
    Mar 4, 2020 Tauranga, New Zealand 19 24 39565074 @murray7 Link
    Mar 4, 2022 Woy Woy, New South Wales, Australia 22 25 107852236 @mosspit Link
    Mar 5, 2022 Bunya Mountains, Queensland, Australia 19 30 108617605 @debmetters Link
    Mar 8, 2022 Twin Waters, Queensland, Australia 22 35 108169367 @f_martoni Link
    Mar 16, 2019 Otahuhu, New Zealand 17 26 71156198 @mike68lusk Link
    Mar 16, 2020 East Barron, Queensland, Australia 21 32 41656251 @damontighe Link
    Mar 22, 2017 Warrimoo, New South Wales, Australia 22 31 82529076 @recorderer Link
    Mar 22, 2021 Bundaberg, Queensland, Australia 24 28 71743271 @annarose75 Link
    Mar 23, 2021 Calliope, Queensland, Australia 25 30 71858265 @teale_britstra Link
    Mar 25, 2023 Smithfield Conservation Park, Queensland, Australia 23 31 152303222 @zoologistmitch Link
    Mar 24, 2021 Bloomfield, Queensland, Australia 24 31 71985369 @dianneclarke Link
    Mar 27, 2023 Bloomfield, Queensland, Australia 20 29 152472963 @dhruthi2 Link
    Apr 1, 2023 Gateway Island, Victoria, Australia 11 20 153536645 @tmacvean Link
    Apr 4, 2023 Toormina, New South Wales, Australia 18 25 153549623 @nicklambert Link
    Apr 16, 2018 The Entrance North, New South Wales, Australia 16 28 11142357 @regb Link
    May 14, 2022 Chillagoe, Queensland, Australia 21 29 117118615 @jake_nz Link
    May 17, 2022 Kuranda, Queensland, Australia 19 29 117420214 @nathaniel159 Link
    Oct 13, 2022 8 Innot Hot Springs, Queensland, Australia 23 30 139786440 @louisveilex Link
    Dec 10, 2022 Jaggan, Queensland, Australia 26 32 172561222 @karena_mcleod Link
    Dec 13, 2018 Innot Hot Springs, Queensland, Australia 25 31 145543364 @xybo Link
    Dec 28, 2021 Lee Point, Northern Territory, Australia 24 32 103799523 @jameslambo Link


    Date Location Low (°C) High (°C) Observation User Link
    Mar 7, 2022 Thrissur, Kerala, India 29? 31 108106907 @sreenivasan Link
    Apr 17, 2023 Dakshina Kannada, Karnataka, India 30? 30? 155289350 @poorna_sona Link
    May 2, 2022 Hebri, Karnataka, India 26 33 120806599 @harshithjv Link
    May 3, 2021 Udham Singh Nagar, Uttarakhand, India 26 37 77009421 @kamleshatwal Link
    May 4, 2023 Kochi, Kerala, India 30? 30 159663207 @renju Link
    May 8, 2023 Bardhaman, West Bengal, India 23 36 160541349 @sunny122 Link
    May 9, 2023 Bardhaman, West Bengal, India 29 42 160716481 @puspak_roy Link
    May 16, 2021 Miyazaki-shi, Japan 24? 26? 143272879 @sindhuharidas Link
    May 18, 2020 Palakkad, Kerala, India 23 28 46345693 @abhiramic Link
    May 24, 2022 Bengaluru, Karnataka, India 22 31 118509898 @dhruthi2 Link
    May 24, 2022 Margao, Goa, India 28 34 118495686 @chandruchawla Link
    May 29, 2021 Bardez, Goa, India 26 31 80691388 @mrinalini_sen Link
    Jun 4, 2020 Bengaluru, Karnataka, India 23 30 48421532 @kabirbhartur Link
    Jun 17, 2023 Rāmantali, Kerala, India 25 33? 168099497 @sindhuharidas Link
    Jun 25, 2022 Annāmalaihalli, Tamil Nadu, India 21? 28 123496704 @vinod_shankar Link
    Jun 30, 2019 Miyazaki-shi, Japan 27 29 27921330 @psyconaut Link
    Jul 30, 2022 New Delhi, Delhi, India 26 32 143698444 @saraptor Link
    Jul 1, 2023 Thane, Maharashtra, India 24 29 170488642 @anil_kumar_verma Link
    Jul 2, 2023 Udham Singh Nagar, Uttarakhand, India 27 33 170656573 @kapil_chand Link
    Jul 3, 2021 Central and Western District, Hong Kong 30 32 86011443 @pasteurng Link
    Jun 6, 2021 Lantau Island, Hong Kong 27 32 81872873 @thomas303 Link
    Jul 8, 2023 Thane, Maharashtra, India 27 31 170488642 @anil_kumar_verma Link
    Jul 8, 2023 Mātherān, Maharashtra, India 27 31 179092198 @rajivthanawala Link
    Jul 8, 2023 Bankura, West Bengal, India 27 33 171760762 @aniruddha_singhamahapatra Link
    Jul 9, 2021 Salem, Tamil Nadu, India 28 37 86266647 @thaniwildbook Link
    Jul 9, 2023 Pānch Mahāls, Gujarat, India 27 30 171969097 @birderbaba Link
    Jul 10, 2020 Tirupati, Andhra Pradesh, India 23 31 142214051 @kaushikkhandode Link
    Jul 10, 2023 Kolkata, West Bengal, India 29 34 172145361 @wild_wild_nature Link
    Jul 12, 2023 Ratnagiri, Maharashtra, India 27 29 173577013 @sharadavakil Link
    Jul 13, 2023 Thiruvananthapuram, Kerala, India (debris bag) 27 30 172835746 @pcbose Link
    Jul 14, 2017 Kyoto, Japan 26 33 143752944 @krypto60 Link
    Jul 17, 2021 East Godāvari, Andhra Pradesh, India 24 31 87538529 @rajabandi Link
    Jul 18, 2023 Kota, Rajasthan, India 26 30 173546040 @sonukumar055 Link
    Jun 22, 2020 Aynode, Maharashtra, India 26 30 50556363 @sanjay10 Link
    Jul 22, 2023 Kevdi, Gujarat, India 28 34 174173440 @foram_bee Link
    Jul 23, 2023 Kevdi, Gujarat, India 26 27 174666515 @drpadhiyar Link
    Jul 23, 2021 Amritsar, Punjab, India 28 34 88506019 @shailjakumari Link
    Jul 27, 2023 Ballari, Karnataka, India 23 29 175172044 @siddhantmhetre09 Link
    Jul 27, 2023 Pāmulaparru, Andhra Pradesh, India 26 29 175143694 @thota Link
    Jul 28, 2022 Vidyānagar, Maharashtra, India 25 33 136925302 @mayurnandikar Link
    Aug 10, 2020 Bālāpur, Maharashtra, India 25 29 56012320 @kulbhushansingh Link
    Aug 17, 2023 Mātherān, Maharashtra, India 28 35 178822784 @kamleshatwal Link
    Aug 18, 2020 Ahmedabad, Gujarat, India 26 31 57339737 @evamarieveroeveren Link
    Aug 22, 2018 Chernigovskiy Rayon, Russia 18 27 16353722 @olgafromvl Link
    Aug 25, 2021 Mātherān, Maharashtra, India 22 30 92454620 @veenas Link
    Sep 2, 2022 Cuddalore, Tamil Nadu, India 25 33 133428194 @jayarakesh Link
    Sep 3, 2022 Nanjing, Jiangsu, China 22 26 133474780 @xuacc Link
    Sep 4, 2021 Navsari, Gujarat, India 26 31 94344784 @viraljoshi Link
    Sep 4, 2021 Bengaluru, Karnataka, India 21 28 93573616 @subbu107 Link
    Sep 6, 2022 Cuddalore, Tamil Nadu, India 27 33 133861681 @kumargeo Link
    Sep 16, 2021 Bengaluru, Karnataka, India 21 29 36859401 @kiranghadge Link
    Sep 16, 2021 New Delhi, Delhi, India 25 29 95183358 @svabhukohli Link
    Sep 19, 2020 Ernākulam, Kerala, India 24 26 60081064 @sunnyjosef Link
    Sep 26, 2022 Prayagraj, Uttar Pradesh, India 25 31 136536186 @chandan_dalawat Link
    Sep 30, 2021 Tainan, Taiwan 27 33 96773910 @wangfoofoo Link
    Oct 3, 2021 Bengaluru, Karnataka, India 22 29 96980692 @radioactivenerd Link
    Oct 21, 2021 Tirunelveli, Tamil Nadu, India 25 31 98981006 @thaniwildbook Link
    Oct 24, 2020 Kancheepuram, Tamil Nadu, India 25 34 63775176 @samuelprakash Link
    Nov 14, 2021 Puducherry, Pondicherry, India 24 28 106508595 @satyaswaroopnanda Link
    Nov 14, 2022 Tirupati, Andhra Pradesh, India 22 26? 143164224 @vikramchandra_alladi Link
    Nov 19, 2021 Salem, Tamil Nadu, India 24 32 101524879 @thaniwildbook Link


    This table may be periodically updated with new observations which improve the accuracy of the data. As of 26/09/23 it contains 200 observations. Copying this data into Excel and using the min, max and average functions (which automatically ignore data marked with ?) results in the following:

    Low (°C) High (°C)
    Minimum -2 14
    Maximum 30 42
    Average 21.65 29.23

    Observation 167425167 has the lowest temperature with -2°C so deserves closer scrutiny. This temperature was recorded during fog at 08:00 on the day of the observation in Paraná, Entre Rios, Argentina. The observation was made at 12:49 in Parque Nacional Pre Delta some 42 kilometers south of Paraná but timeanddate does not have a location for the park itself and for nearby Diamante and Strobel the weather given is the same so is presumably from the weather monitoring station in Paraná. The temperature rose to 3°C by 09:00 and then 11°C by 11:00 and it was 12-13°C at the time of the observation. Cold temperature were also recorded earlier in the day of 0°C from 04:00 to 07:00 and an overnight temperature of 1 or 2°C in the hours before. The two days prior to the observation had similar temperatures. The more distant weather monitoring station in Córdoba recorded even colder temperautres of -6°C on this day. The park is noted as having an annual average temperature of 19°C with a humid and tropical environment as a result of the river having a moderating influence.[1]

    It is therefore uncertain what temperature occurred in the park on this day but unless the park has a significantly different microclimate it was presumably cold. The level of maturity of the mushrooms suggests they started growing at least a day or two earlier so would have been exposed to the overnight temperatures.

    The next lowest temperature was 6°C in observation 179607697 from Peru in January.

    The minimum high of 14°C also comes from the observation with a -2°C low and a second observation has a potential high of 14°C but is lacking data. The next minimum high is 18°C.

    The highest temperature of 42°C is from observation 160716481 from India in May. The observation was made at 12:30 and a more detailed look at the temperatures that day reveals 40°C at 11:30 and 42°C at 14:30 with no data provided in between. So the temperature during this observation can be assumed to be at least 40°C. Some of the less mature primordia are aborting as is seen by the yellowing and browning as well as the dry, shrivelling look. The older ones look a little dry with some browning developing and some intermediary ones have spliiting stems so they do not appear to be growing very well. The two days before saw high temperatures of 42 and 40°C however and it did not go below 26°C during this period so the mushrooms visible will have grown during some of this extreme heat. Numerous primordia aborting whilst a few grow large is not uncommon and it cannot be assessed whether this was the result of the heat though desiccation as a result of the extremes seems likely.

    The next highest is 37°C with two observations, 86266647 and 77009421 in India at this temperature. Both obervations show good growth with no sign of distress and both were made a few hours after the highest temperature with the mushrooms mature enough that they must have developed before then.

    Also of note is observation 69376855 recorded on the 17th of November 2018. The low and high temperatures of 24/32°C are fairly consistent across the month and nothing especially noteworth in themselves however on the day after the observation a sudden drop in temperature is recorded from 29°C with showers at 13:00 to 6°C and thunderstorms at 13:18 and then back up to 24°C with thunderstorms at 14:00. Similar is observed earlier in the month on the 6th with a drop from 31°C to 6°C with precipitation in a one hour period and then back up to 26°C. This same trend is seen in past weather data for the region during November and December often with a few such storms per month. It would be interesting to see what impact these cold snaps accompanied by rain and storms have on the fungus.

    Observation 104687663 is interesting due to the presence of both L. cretaceus and L. birnbaumii near each other. This is not unique and is found in several observations but is suggestive of similar conditions being favourable for both species.


  • [1] "Predelta National Park (Parque Nacional Predelta)"ermakvagus.com
  • Publicado el 26 de septiembre de 2023 14:26 por mycomutant mycomutant | 3 comentarios | Deja un comentario

    18 de noviembre de 2022

    Leucocoprinus cretaceus and the Complications of Identifying Leucocoprinus Species After Heavy Rainfall

    Like other scaly mushrooms such as Amanita and Chlorophyllum species, the appearance of the caps of certain Leucocoprinus species are prone to much change as a result of these scales washing away in rain. A good demonstration of this is Leucocoprinus cretaceus since it is quite distinct and retains characteristics that often enable it to be identified without too much confusion even after heavy rainfall. For instance in this photo we can see that the caps have largely become smooth with only the center scales being retained. White debris from the caps is visible on the wood below, as is the dry spot on the wood where it has been sheltered by the caps. Also sheltered are the stems which have retained their distinctive white scales.

    Observation 138735331 - Leucocoprinus cretaceus after rainfall Credit: @geovane_siqueira

    Despite losing some of their distinctive features it is still clear that these mushrooms are Leucocoprinus cretaceus, however for other Leucocoprinus species rainfall may pose a greater issue for identification and result in them looking like another species.

    The species most commonly confused with Leucocoprinus cretaceus on iNaturalist appears to be Leucocoprinus cepistipes. The two are similar with both displaying clustered, caespitose growth behaviour often on woodchips, rotting wood or compost. Both species have some degree of white scales on the caps, however these are far more pronounced and warty on L. cretaceus and much finer on L. cepistipes. Additionally L. cepistipes has a distinct, brownish central disc which is broadly umbonate in immaturity and a smooth stipe that is often prone to clear exudation collecting towards the base. These droplets can be mistaken, at a glance (or by the image recognition app) for the scaly white stem base of L. cretaceus. L. cretaceus can display some brown or yellowish discolouration at the centre of the cap and the white coating may rub off the stipe revealing a brownish or yellowish surface which may result in confusion with L. cepistipes.

    When rainfall removes the features of either species they can more closely resemble each other and are easier to mistake. The caps of both are prone to splitting as they become heavily saturated resulting in scales and white debris from the cap littering the ground around. Additionally a slight brown tone at the centre of the cap on Leucocoprinus cretaceus may become more noticeable.

    Observation 86218038 - Soggy L. cepistipes Credit: @churley_25

    Observation 73094381- Soggy L. cretaceus Credit: @hughianni

    Leucocoprinus cretaceus

    There is a possibility that observations for L. cretaceus may include a number of more obscure, less well known species. For instance Leucocoprinus elaeidis and Leucocoprinus nanianae are described very similarly but note some yellow discolouration. The spore sizes described for all three species are virtually identical however and it seems likely that these may just be synonyms that have yet to be reclassified due to them being forgotten in such obscure books. No information exists for either online beyond the initial description and some old sketches for L. elaeidis and their listings in Mycobank and Species Fungorum as current species.

    The book L. nanianae was described in turned out to be so uncommon that in the end I only managed to find it by reaching out to a rare book shop in France which happened to have a copy so I am très grateful to Etienne at Arcala Livres Anciens for the assistance in sending me photos. It is of course very likely that plenty of organisations do hold this book although I did note that every species described in it lacks any information online so it may indeed be rare. Due to the entirely broken copyright system we have which stipulates that work arbitrarily remains in copyright until 70 years after the authors death, the Biodiversity Heritage Library only have digitised volumes of Bulletin de l'Académie Malgache up to 1925. These nonsensical laws driven solely by corporate greed result in old, boring scientific texts which are not in print, will never again be put in print or turn a profit for the likely dead authors (and often defunct organisations) being essentially hidden from the world for absolutely no reason. A constant thorn in my side when attempting to research these old species is finding that Google books has a fully digitised and searchable copy of the book online but will not let me see it because 'it is still in copyright' with any requests for content being ignored. But I digress...

    Leucocoprinus breviramus also has some similarities to L. cretaceus in the description but enough that it might be possible to distinguish it from L. cretaceus. This species was more recently described and was compared to L. cretaceus so does seem likely to be distinct and there are possibly some observations of it on iNaturalist which need exploring. Hopefully by collecting everything that appears to be L. cretaceus in one place it will become easier to find distinctions. Already I have collected a number of observations together which I am not satisfied to just identify and dismiss as L. cretaceus which I suspect may be L. breviramus or another species due to the excessively floccose details.

    Other mushrooms that are often mistaken for L. cretaceus by the image recognition algorithm include some members of Amanita sect roanokenses, some of the white, scaly Leucoagaricus, Chlorophyllum and Cystolepiota species and some puffballs. These are generally simple enough to separate out under normal circumstances however when very immature or when rainfall has removed cap features these species are likewise easier to confuse.

    Leucocoprinus cretaceus without rain damage

    Observation 26249347 Credit: @teodoro_chivatabedoya | Observation 26249347 Credit: @teodoro_chivatabedoya | Observation 68176921 Credit: @hughianni | Observation 139959458 Credit: @loonathegarden

    Leucocoprinus cretaceus after rain

    Observation 51654912 Credit: @conservation_partnerships_ipswich | Observation 132191704 Credit: @parahuaco | Observation 112907030 Credit: @markwheatley | Observation 139959098 Credit: @loonathegarden

    Publicado el 18 de noviembre de 2022 17:21 por mycomutant mycomutant | 0 comentarios | Deja un comentario

    17 de octubre de 2022

    Favourite finds of today 17/10/22

    I've spent most of the day combing through unidentified fungi in Costa Rica looking for anything which might be another unusual coprinoid. Some results were found:


    However more interesting for me were all the things I found along the way.

    Myrmecopterula velohortorum

    Observation 36167883 Image copyright: @sarahkuppert

    I had never seen this before outside of the photos in the paper describing it [1] so this was a lucky find. Unfortunately the taxon doesn't exist on iNaturalist yet so for now it is just identified as Myrmecopterula (I don't know how long it takes for a curator request to be approved). This species was classified as Pterula velohortorum in 2014 [2] and reclassified under the novel genus Myrmecopterula in 2020 [1] however the old name is not in iNaturalist either and the species is largely unknown so this could be one of the first identifications of it on iNaturalist outside of the small number of observations of nests of Apterostigma. I suppose this raises the question of whether such an observation is better identified as belonging to the ants or belonging to the fungus. In this instance I would suggest fungus since only one ant is faintly visible in the shot however for mutualistic species such as this it would be nice if observations could be identified as both species to aid in the identification of them.

    I only know anything about Myrmecopterula because I stumbled upon it whilst trying to research the potential association between some Leucocoprinus species and leaf cutter ants. The most commonly farmed ant fungi was reclassified as Leucoagaricus gongylophorus and I was unable to find much definitive information (which wasn't out of date) on any current Leucocoprinus species which are farmed. However in the process I ended up writing the Wikipedia pages for the Myrmecopterula genus and the three named species and learning about that instead.

    M. velohortorum is a fungus cultivated by ants belonging to the Apterostigma dentigerum subclade. The nests are suspended under logs or from trees and covered by a mycelial veil woven from the fungus. The nests only have one hole to enter and exit which is seen to the left of this image complete with an ant in the doorway. So the identity of this species is certain (barring any future discoveries or classifications of related species, there are some species of Myrmecopterula that have yet to be formally classified).

    M. nudihortorum is similar but it is not found cultivated in hanging gardens but rather in shallow recesses in the ground. It also is not covered by a mycelial veil so the two are easily distinguished and in turn this distinction helps identify the ants. Neither species has been observed to produce fertile mushrooms and they are therefore thought to be dependent on the ants.

    Myrmecopterula moniliformis

    This related species has been shown to produce both fertile and infertile forms and is hypothesized to have escaped cultivation in the past. The fertile fruiting bodies may resemble the fine coral shapes of Pterula species whilst the infertile ones give it the specific epithet moniliformis meaning bead or necklace shaped. Again, barring further discoveries and reclassifications of unnamed Myrmecopterula species this is a relatively simple mushroom to identify but it is simply fairly unknown.

    Observation 97520272 Image copyright: @ale_vasquez

    Observation 31675982 Image copyright: @andreagreening

    These two observations seem certain and the first even appears to be growing from an ant mound. This species is observed growing from abandoned ant mounds and is thought to play a role in breaking down the residual matter left from a dead nest, although there is some speculation that it may also grow parasitically on living ones. Unlike the two other named species in this genus, M. moniliformis is not dependent on the ants and may grow from the ground with or without ant nests being present.

    The third observation I identified as Myrmecopterula moniliformis is less certain.

    Observation 108207690 Image copyright: @rkostecke

    The trouble is that the same area which hosts Myrmecopterula also appears to have a startling diversity of Xylaria species, far more than I am used to in the non tropical habitat that I call home. The shape of the sterile form of M. moniliformis can appear similar to some of these such as Observation 119753999 and Observation 108775547 which appear more likely to be Xylaria owing to the apparent black colouration where the white surface is scraped off and the hint of black towards the stem base. Whereas when the surface of M. moniliformis is damaged it seems to show a brownish-red colour and sometimes exhibits the same towards the base. The white, chalky surface is otherwise similar so when M. moniliformis is not exhibiting its chaotic branching bead like structure and is in a more simple form it may be easier to confuse. However this particular observation looks very similar to the exceptionally picturesque one made by @teodoro_chivatabedoya only without additional beading on top of it.

    It seems possible that a search for identifications of Xylaria species in these regions may yield some misidentified specimens of M. moniliformis owing to it not being commonly known.


    [1] 'Reclassification of Pterulaceae Corner (Basidiomycota: Agaricales) introducing the ant-associated genus Myrmecopterula gen. nov., Phaeopterula Henn. and the corticioid Radulomycetaceae fam. nov.'

    [2] Phylogenetic Placement of an Unusual Coral Mushroom Challenges the Classic Hypothesis of Strict Coevolution in the Apterostigma Pilosum Group Ant–fungus Mutualism

    Publicado el 17 de octubre de 2022 15:20 por mycomutant mycomutant | 1 comentario | Deja un comentario