24 de julio de 2023

Devastated by development next to Lake Georgetown

A few weeks ago I learned of another new proposed development in Williamson County - this one called Lakeside Estates on the northwest end of Lake Georgetown. According to news reports and a presentation to the Georgetown city council, the developer's initial plans include approximately 1645 homes on 722 acres right next to the borders of Lake Georgetown. While I had sadly become desensitized to the fact that corporate capitalism wants to turn every last acre of Williamson county into one colossal suburban development, this particular development struck a nerve since for many years I considered that area of Lake Georgetown to be one of the most scenic in the county. For years, I have hiked the Goodwater Trail from Camp Tejas to a hillside (30.68477,-97.79659) not far from mile marker 8 where the trail emerges from a wooded hillside to an astounding view that includes the North San Gabriel River slowly widening and turning into Lake Georgetown not far downstream. After hiking for a number of hours, this area became a great place to rest and enjoy, not only the view, but also the peace and solitude away from the suburban development which has crowded against other borders of the lake. It truly was a refuge from the blitzkrieg of development, from the construction noise, lawnmowers, leaf blowers, car noise, dogs barking and so on that seems to now accompany many hiking trails in Williamson county. Now it will likely include all of those things, and the view, which mostly included the river, the lake, and at most a few expensive houses on the hills across the river, will now include at the very least numerous houses on the adjacent hillside. It will be a refuge no more, just another sad reminder of the voracious, uncontrolled expanse of humanity.

Unfortunately, the more I investigated the worse things appear to be. The initial plans show that most of the development would be significantly more dense than almost any other development adjacent to the lake. Despite the presence of some number of one acre lots around some of the edges of the property, most of the 1645 homes would be crowded onto 300 or so acres probably similar to the neighboring behemoth Santa Rita Ranch, simply obliterating the native landscape and ecology, almost all within a mile of the Goodwater Trail. As a naturalist and botanist, my heart breaks to think of all the flora and fauna that will be erased in favor of more rooftops, turf grass, and pavement. In fact, like most areas that have been developed we will likely never know all the flora and fauna of the area. There are only a handful of iNaturalist observations for the tract at the moment. It is possible that there is habitat for one or more endangered or threatened species there such as the Golden Cheeked Warbler, but that does not protect the land, it simply means the developer might have to pay an additional fee for impacted habitat that might go towards preserving habitat elsewhere. The prospect of this tract escaping destruction seems minimal. And so this development will take this once quiet area and bring the worst of suburbia to it.

A few links:
Story from KXAN
Developer presentation to Georgetown City Council on June 27, 2023
Spot on Goodwater trail northeast of development

Publicado el julio 24, 2023 06:05 TARDE por rymcdaniel rymcdaniel | 2 comentarios | Deja un comentario

01 de septiembre de 2022

Discoid Grindelia squarrosa back to Grindelia nuda again

Grindelia nuda is a rayless (eradiate/discoid) species of Grindelia with blunt or rounded leaf teeth terminated with glands, defined initially by Wood(1878) based on a collection in what is now Oklahoma. For much of its history, it has been treated as a variety of Grindelia squarrosa (Gray 1884; Steyermark 1934; Correll and Johnston 1970) and briefly again as G. nuda (Nesom 1990; Diggs et al 1999) until is was synonomized with Grindelia squarrosa in the Flora of North America by Strother and Wetter(2006). Plants of the World Online (POWO), which iNaturalist uses as its main resource for botanical names, followed this synonomy until some unspecified time in the last couple of years (perhaps following a change in the September 2021 release of the World Checklist of Vascular Plants) when it accepted Grindelia nuda as a valid species again, referencing Powell and Worthington's Flowering Plants of Trans-Pecos Texas and Adjacent Areas. There has been a fair amount of resistance to some of the taxonomy of Strother and Wetter in at least one comprehensive treatment (Bartoli and Tortosa 2012) and a number of regional floras (Moore 2012; Ackerfield 2015; Powell and Worthington 2018), but that is a broader discussion.

On iNaturalist, G. nuda was never synonomized with G. squarrosa due to flagging in 2016 to maintain it as an accepted name. Despite that, following the FNA and POWO, I (and maybe others) identified most G. nuda specimens up to this point as G. squarrosa. As a result, there are at least several hundred specimens (based on research grade specimens of G. squarrosa in Texas) that will need to be reidentified as G. nuda at some point. In Texas, this should be fairly straightforward since G. nuda is the only rayless (eradiate/discoid) species in the state except for the rare G. oolepis in South Texas. However, it will be a manual process as there are a few actual G. squarrosa in northeast Texas. POWO, following Powell and Worthington (which follows Nesom 1990), recognizes two varieties of G. nuda, var. nuda and var. aphanactis. These appear to be distinguished mostly by leaf morphology (specifically the length to width ratio), and might be difficult to differentiate in the field. However, Nesom indicated that var. nuda occurs mostly to the east in Texas, Oklahoma, Kansas and southeast Colorado while var. aphanactis occurs to the west mostly in New Mexico, southern Colorado, and Arizona. He also recognized a zone of intermediacy in areas of west Texas. It is also worth noting that genetic evidence in Moore et al(2012) indicates that the two may be separate species, despite their great morphological similarity, so it is plausible that the two varieties may be separated in the future.

Heads from above (Burnet, Williamson, and Kimble counties in Texas)

Head profile

Leaves, typically cauline mid-stem

Observations used in this post

Burnet county : 62455288
Williamson county: 8003651
Kimble county: 97271324


Ackerfield, J. 2015. Flora of Colorado. BRIT Press.
Bartoli, A. and R.D. Tortosa. 2012. Revision of the North American species of Grindelia (Asteraceae). Ann. Missouri Bot. Gard. 98: 447–513.
Correll, D.S. & M.C. Johnston. 1970. Manual of the Vascular Plants of Texas. Texas Research Foundation, Renner, Texas.
Diggs, G. M., Lipscomb, B. L., O'Kennon, B., Mahler, W. F., & Shinners, L. H. 1999. Shinners & Mahler's Illustrated Flora of North Central Texas. Botanical Research Institute of Texas.
Gray, A. 1884. Synoptical Flora of North America 1(2): 118.
Moore, A.J. 2012, Grindelia, in Jepson Flora Project (eds.) Jepson eFlora, https://ucjeps.berkeley.edu/eflora/eflora_display.php?tid=451, accessed on August 30, 2022.
Moore, A.J., Bartoli, A., Tortosa, R. D., & B.G. Baldwin. 2012. Phylogeny, biography, and chromosome evolution of the amphitropical genus Grindelia (Asteraceae) inferred from nuclear ribosomal and chloroplast sequence data. Taxon 61(1): 211-230.
Nesom, G. L. 1990. Studies in the systematics of Mexican and Texan Grindelia (Asteraceae: Astereae). Phytologia 68: 303–332.
POWO. 2022. Plants of the World Online. Facilitated by the Royal Botanic Gardens, Kew. Published on the Internet; http://www.plantsoftheworldonline.org/ Accessed 30 August 2022. https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:210628-1
Powell, A.M. & Worthington, R.D. 2018. Flowering plants of Trans-Pecos Texas and adjacent areas: 1-1444. BRIT Press.
Steyermark, J. A. 1934. Studies in Grindelia. II. A monograph of the North American species of the genus Grindelia. Ann. Missouri Bot. Gard. 21: 433–608.
Strother, J. L. and M. Wetter. Grindelia. In: Flora of North America Editorial Committee, eds. 1993+. Flora of North America North of Mexico. 20+ vols. New York and Oxford. Vol. 20. http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=114086
Wood, A. 1878. Grindelia nuda. Botanical Gazette 3(6): 50. 1878.


All photos used in this post are the property of Ryan McDaniel, all rights reserved.


0.1 - September 1, 2022 - Initial.
Publicado el septiembre 1, 2022 05:52 TARDE por rymcdaniel rymcdaniel | 18 comentarios | Deja un comentario

03 de junio de 2022

Zeltnera texensis and Centaurium species in Texas


Three similar looking species in the Gentianaceae family, Zeltnera texensis, Centaurium pulchellum, and Centaurium teniuflorum likely come in contact in various parts of central and eastern Texas and can be difficult to differentiate due to similar corollas. Previous to 2004, these three species were all in the genus Centaurium and were differentiated with characters like pedicel length and form of the inflorescence, among others (Diggs et al 1999). In 2004 (Mansion 2004), the new world species of Centaurium were segregated into Zeltnera based on the different shape and separation of stigma lobes compared to those of the old world. Unfortunately, these details are rarely captured by observers on iNaturalist, which makes rigorous identification based on these characters unlikely. A less rigorous identification may be done using the characters previously used, based roughly on the key in Shinners & Mahler's Illustrated Flora of North Central Texas (FNCT), substituing C. texense with Z. texensis and C. floribundum with C. tenuiflorum. Features have been collected in the following table from various sources (Holmes and Wivagg 1996, Mansion 2004, Pringle 2010, and Weakley 2022 (based on Struwe and Pringle 2018)). It is incomplete due to the difficulty of accessing more comprehensive works which are typically unpublished, so I have attempted to fill in some gaps in the data with data gleaned from an informal examination of images of herbaria specimens and my own personal experience.

Useful features for identification of Zeltnera texensis and Centaurium species in Texas
Feature Z. texensis C. pulchellum C. tenuiflorum
Stigmaa fan shaped reniform or shoe shaped reniform or shoe shaped
Stylea not divided slightly bifid slightly bifid
Pedicel usually greater than 1/2 as long as calyces, occasionally shorter, 4-14mmb shorter than calycesc (1-)3-5(11)mm d sessile or subsessiled-f, no greater than 2mme*
Inflorescence monochasial helicoid cymea open-spreading compound dichasiumf: diffuse not corymboide dense flat topped umbellate cymef, dense corymboide
Leaves stem leaves linear to lanceolate, 1-3(4)mm widec stem leaves lance-ovate to lanceolate, 2-7mm widec TBD
Height 7-25cm b (5)10-18(29)cmf (19)27-45(55)cmf
Branching typically just below midstem, occassionally near base or upper stemb midstem or belowf upper 1/3 - 1/4 of stemf
a Mansion 2004; b informal examination of 10 specimens from Texas and Missouri from SEInet and personal experience; c Diggs et al 1999 d Weakley 2022; e Pringle 2010, *pedicel length up to 2mm maybe overridden by later treatment in Weakley; f Holmes & Wivagg 1996

The FNCT keyed the three following small flowered species of Centaurium: Centaurium texense, Centaurium pulchellum, and Centaurium floribundum, with a mention of C. tenuiflorum in the text of C. puchellum. Since its publication, Centaurium texense has changed to Zeltnera texensis (Mansion 2004, Pringle 2011) (though with some nomenclatural hiccups) and the specimens treated as Centaurium floribundum from Texas are now treated as Centaurium teniuflorum (Pringle 2010). With the understanding of the name changes, the easiest distinction to be made appears to be between Centaurium teniuflorum and the other species, due to its sessile or subsessile pedicels and tendency to form a dense flat topped inflorescence. Differentiating Z. texensis and C. pulchellum would likely be more difficult from photographs due to the subtle differences in pedicel length and leaf shape and dimensions. However, it is unclear if C. pulchellum and Z. texensis are found in the same areas at this point. Specimens that cannot be clearly identified will likely need to be assigned to subtribe Chironiinae

Historical distributions

The historical distribution of Z. texensis in Texas is unclear. The current BONAP map has a fairly wide distribution of Z. texensis, ranging from the eastern hill country northward through north central Texas almost to the Oklahoma border and also eastward to the Houston area. Additional occurrences seem to be found in parts of Oklahoma, Louisiana, Arkansas and Missouri. The reference for Texas is listed as "TX: 1967. Catholic University of America Biological Series", which is most likely an unpublished dissertation by Dunn dating from 1967 (A revision of the genus Centaurium of continental United States), but I suspect data from other sources may have been included. In contrast, Turner (1993), using samples mostly from Tex/LL, showed a much narrower range concentrated around the Balcones Escarpment and eastern hill country, extending rather weakly to almost disjunct occurrences in Tarrant and Dallas counties. He did not address occurrences outside of Texas. Given the occurrence of Z. texensis mostly on eroding limestone slopes and soils, I suspect Turner's distribution may be more likely., though examination of later collections has added more specimens in north central Texas in the counties around DFW and even along the Red River, though not so much towards the Houston area. Holmes and Wivagg (1996) indicated that C. pulchellum was often misidentified as Z. texensis, so that may account for the wider distribution on BONAP.

Historical distributions of Centaurium pulchellum and Centaurium tenuiflorum in Texas are based mostly on Holmes and Wivagg(1996). In their work, they identified larger, more densely flowering plants as C. muhlenbergii(a species of the west coast United States), indicating that they had previously been misidentified as either C. pulchellum or C. texense. These Texas specimens were for a brief time treated as C. floribundum (Diggs et al 1999) and now have been identified as C. tenuiflorum (Pringle 2010). At the time, C. pulchellum appeared mostly in the southeast portion of the state (Brazos, Galveston, Hardin, Harris, Jasper, Liberty, and Orange counties). C. tenuiflorum (there treated as C. muhlenbergii) was found mostly in a number of counties south of Dallas/Fort Worth and northeast of Austin (Ellis, Falls, Freestone, Hill, Johnson, Leon, Limestone, McLennan, Milam). I have personally seen it in Williamson county, just to the southwest of its reported range and based on soon to be corrected iNaturalist observations in the DFW area, it has also spread northward (see later discussion on survey of iNaturalist observations). Both species have apparently been in Texas since at least the early 1970s (Holmes and Wivagg 1996).

Based on the distributions found in Turner and Holmes and Wivagg, it seems most likely that the ranges of Z. texensis and C. tenuiflorum might overlap. It is less clear if C. pulchellum may have been likely to spread from southeast Texas into the narrow historic range of Z. texensis described by Turner. If so, problematic specimens in that area may have to be assigned to a higher taxon.

Differentiation using the stigmas

Photographing the stigmas of these species is difficult given their small size. Line drawings showing stigma shapes of similar species of Zeltnera and Centaurium can be found in Mansion (2004) and Pringle (2010). Stigmas of Zeltnera species are described as being "fan-shaped" while those of Centaurium are described as being more "shoe" or "iron" shaped.

Z. texensis

C. tenuiflorum

Differentiation based on pedicel length and inflorescence

Differentiation based on pedicel length is most likely on the extreme ends. While the FNCT key indicates that the pedicels are usually nearly as long as the calyces on Z. texensis, the actual length seems to vary, likely from about 1/3 the length of the calyx to being slightly longer than the calyx. It is likely however that at least some and possibly most will be near the length of the calyx. Specimens with shorter pedicels may be difficult to differentiate.

Z. texensis

C. tenuiflorum

Small survey of Z. texensis and Centaurium observations

Out of curiosity of what distinguishing features might be shown in iNaturalist observations of these species, I examined research grade observations for Z. texensis andCentaurium species from Tarrant and Travis counties. As of May 29, 2022, Tarrant county, which is thought to be on the north part of the range in Texas, had a total of 164Z. texensis observations, 115 of those being research grade. Of those, none of the observations included sufficient pictures of the stigma lobes for identification. Only two specimens clearly had a pedicel length consistent with Z. texensis, while numerous ones appeared to have sessile flowers indicative of either C. teniuflorum or C. pulchellum, so most observations identified as Z. texensis appear to have been misidentified. There were only 18 observations of Centaurium species, of which none were research grade, so I did not examine them. Travis county, which is roughly in the heart of the range for Z. texensis, had 146 Z. texensis observations with only 53 marked as research grade. Only one observation (one of mine) had pictures of the stigma sufficient enough for genus ID. In contrast to Tarrant county, most had pedicel lengths consistent with Z. texensis while a few had pedicel lengths consistent with Centaurium species.

I have not yet done a close examination of these species in the southeast part of the state. It is not clear if Z. texensis can currently be differentiated from C. pulchellum using currently available photographic evidence. Intermediate specimens or specimens that don't show the stigmas or pedicels will probably have to be assigned to a higher taxon. Some specimens are being identified as Z. texensis there though. As of May 29, 2022, Harris county had 58 observations of Z. texensis, but the vast majority of similar species were identified as Centaurium (178).

Observations used in this post

C. tenuiflorum : 119653908
Z. texensis : 118706199


Diggs, G. M., Lipscomb, B. L., O'Kennon, B., Mahler, W. F., & Shinners, L. H. (1999). Shinners & Mahler's Illustrated Flora of North Central Texas. Botanical Research Institute of Texas.
Holmes, W. C. and D. C. Wivagg (1996). Identification and distribution of Centaurium muhlenbergii (Griseb.) Piper and C. pulchellum (Sw.) Druce (Gentianaceae) in Louisiana, Mississippi and Texas. Phytologia 80: 23-29.
Kartesz, J.T., The Biota of North America Program (BONAP). 2015. North American Plant Atlas. (http://bonap.net/napa). Chapel Hill, N.C. [maps generated from Kartesz, J.T. 2015. Floristic Synthesis of North America, Version 1.0. Biota of North America Program (BONAP). (in press)].
Mansion, G. (2004). A new classification of the polyphyletic genus Centaurium Hill (Chironiinae, Gentianaceae): description of the New World endemic Zeltnera, and reinstatement of Gyrandra Griseb and Schenkia Griseb. Taxon 53: 719-740.
Pringle, J. S. (2010). The identity and nomenclature of the Pacific North American species Zeltnera muhlenbergii (Gentianaceae) and its distinction from Centaurium tenuiflorum with which it has been confused. Madrono 57: 184-202.
Pringle, J. S. (2011). Validation of the name Zeltnera texensis (Gentianaceae). Rhodora 113:514-515.
Turner, B. L. (1993). The Texas species of Centaurium. Phytologia 75: 259-275.
Weakley, A. S. and Southeastern Flora Team (2022). Flora of Southeastern United States. University of North Carolina Herbarium, North Carolina Botanical Gardern.


All photos used in this post are the property of Ryan McDaniel, all rights reserved.


0.1 - June 3, 2022 - Draft.
Publicado el junio 3, 2022 07:10 TARDE por rymcdaniel rymcdaniel | 12 comentarios | Deja un comentario

01 de septiembre de 2021

An examination of Research Grade Observations in the genus Callirhoe


The genus Callirhoe is a genus of showy, mostly reddish and sometimes white flowering plants in the Malvaceae family native to North America. The most recent study of the genus was by Dorr in A Revision of the North American Genus Callirhoe (Malvaceae) published in 1990 and revised for the Flora of North America (FNA) in 2015.

In the spring of 2021, I began informally examining a number of different type of observations in the Callirhoe dataset for various reasons, sometimes to annotate lesser known species, sometimes to verify identifications or sometimes to add identifications. The occurence of some observations of Callirhoe leiocarpa in the Dallas area (outside their known range) in 2020 had sparked my interest in the genus and I returned to it in 2021. Over the course of a couple of months I noticed a non-trivial number of incorrect observations among Research Grade(RG) observations. At some point, my focus switched to looking for incorrect identifications and I began looking through Callirhoe observations in Texas chronologically, spot checking images in the grid view of the iNaturalist explore window, but I did not track how many were incorrect. After looking through numerous observations and getting part way through the year of 2018, I finally decided that it might be interesting to know what sort of error rate was occurring. Given the relatively large number of observations of Callirhoe (over 10,000), I decided to initially examine a small subset, though eventually examined all RG observations from Texas for the years of 2018 and 2019, including some which were likely RG before I previously made an identification, for a total of 1521. I adjusted the set under examination to exclude RG observations where an identification I had made affected the status and to include Needs ID observations where my identification had changed the status from RG. The error rate for the two years combined was about 19.1%.


There are nine species in the genus, of which the following six are found in Texas: C. alcaeoides, C. involucrata, C. leiocarpa, C. papaver, C. pedata, and C. scabriscula, which has not yet been observed on iNaturalist due to its rarity. C. involucrata is the most common and widespread Callirhoe species in North America. It ranges throughout most of Texas, encompassing the ranges of all the other species in Texas except for parts of the range of C. papaver in east Texas. Two additional species, C. bushii and C. digitata, have historically been found close to or along the Texas Oklahoma border, but are not thought to occur in Texas (Kartesz 2015).

Selection of observations

While I did examine all RG observations from Texas from 2018(594) and 2019(937), I was primarily interested in observations which were Research Grade without my interaction. This required some manipulation of the dataset, removing RG observations where my identification was critical to the observation acheiving RG status and adding to the dataset observations where my identification had changed the observation from RG to Needs ID. Observations that were RG where I simply agreed with the previous identifications which made the status RG were left in the totals since my identification had no effect on achieving RG status.

Limiting the observations to the years of 2018 and 2019 in Texas was mostly based on convenience. I initially started with the year 2019, which was attractive because it was a reasonably large data set and also the year for which I had made the lowest percentage of identifications. I initially intended to evaluate only a small subset of the 2019 observations in order to get a rough figure for the error rate, but I eventually examined all of them and added observations from 2018 for comparison. Limiting the observations to Texas was based mostly on my own familiarity with Texas species and comfort with identifying them. With that said, most Callirhoe observations are currently from Texas and it also contains six of the nine known species, five of which have observations on iNaturalist.

Observation numbers were download as CSV files from iNaturalist by filtering by the genus Callirhoe in Texas for the years 2019 and 2018, repectively, accessed on June 3, 2021 and July 9, 2021. Observations were viewed through the iNaturalist web interface. I examined the observations in random order, first from 2019 and then 2018, but made no attempt to mask other data such as the observer or identifiers names, location and so on.

Standard for correctness

I decided to track whether an identification was incorrect rather than correct. The vast majority of observations, even Research Grade ones, do not show the features one would normally use for identification in a taxonomic key, and so it is often not possible to prove what species a specimen is. However, one can sometimes see a feature which disproves the identification. Most often this was something like the presence or absence of an involucel, but a number of features can be used. For species descriptions and identifying characteristics, I referred to the works of Dorr(1990,2015) and Diggs et al (1999). The reader can refer to my previous post "A Short Guide to Callirhoe in Texas" for methods of identification. On rare occasions I would defer primarily to location, typically only in cases where an observation was identified as C. alcaeoides well outside of its known range.

Given the approach of tracking only incorrect identifications, the results here likely represent a lower bound for the error rate for this data set as there are numerous Research Grade observations which likely don't contain enough information to actually prove or disprove a species level identification. Additionally, even though it is sometimes possible to tell if an identification is incorrect, it is not always possible to make a species level identification in these cases. A common example would be an observation identified as C. involucrata, which upon examination shows a lack of an involucel or the presence of a valvate bud. This would disprove the identification of C. involucrata, but may not offer enough proof to distinguish between C. leiocarpa and C. pedata.

There is a larger discussion to be had about what should constitute enough information for an identification, and this discussion unfortunately can devolve into a broader discussion about the purpose and structure of iNaturalist itself which is beyond the scope of this post. As mentioned, most Callirhoe observations do not show the morphological features one would normally use for identification. To be rigourous, one would likely need to identify those observations only to genus level, and this would remove a significant percentage of Callirhoe observations from RG status. For the time being, for this endeavor at least, I have chosen to track and offer identifications on only those which are fairly clearly incorrect (or in the rare case correct) and leave the rest alone. This unfortunately leaves a fair number of observations at RG status which may or may not be correct, which is not a very satisfying solution given that RG status has implications such as affecting the iNaturalist Computer Vision model and observations being exported to external services such as GBIF. Ironically, for Callirhoe, due to the sheer abundance of C. involucrata compared to the other species, there is probably a high likelihood that something identified as C. involucrata actually is C. involucrata, even if it does not show the features one would need for a positive identification.


The error rate for the adjusted dataset for the two years combined was 19.1%. There was a noticeable difference between the two years, at 15.6% for 2018 and 21.4% for 2019.

Incorrect Research Grade Identifications
Year RG Observations Adjusted RG Observations Incorrect Percent Incorrect
2018 594 617 96 15.6
2019 937 904 194 21.4
2018+2019 1531 1521 290 19.1

The identifications which were not deemed incorrect(approximately 80.9% or 1231) were not necessarily correct. They ranged from merely being possible as in cases where only the non-distinguishing features of a flower were shown all the way to correct where all of the distinguishing features required for an identification were clearly shown, though these appeared to be only a small minority. With most of these observations I found it difficult to decide how to separate those which should be identified only to genus and those which could be identified to species based on what morphological features were shown, and I ultimately could not come up with a good solution for the problem. As an initial assessment, I arrived upon the following rough categorization of the non-incorrect identifications, but I found even my own application to be inconsistent and so this is a rough estimate only, possibly to be revisited in the future.

Categories of Possibly Correct Identifications
Category Number Percent Description
Plausible to Likely 647 42.5 Observation showed one or more features supporting the identification which ruled out some but not all other possibilities found in or near the state. Examples could range from partially visible hairs on the sepals to presence of an involucel.
Possible 372 24.5 Observation showed no or only very weakly distinguishing features. Examples were those that showed only the corolla petals or maybe corolla petals appearing close to the ground.
Correct 141 9.3 Observation showed enough features to rule out other possibilities found in the state.
Uncertain 50 3.3 Observation had some quality, sometimes unclear, which warranted raising the identifcation to genus level, though which did not make it clearly incorrect.
Rosette 17 1.1 Observation showed only leaves.


A closer examination of the results revealed at least two trends. First, the majority of erroneous identifications were identified as C. involucrata. This trend is unsurprising. C. involucrata is the most common and widespread species of Callirhoe in North America, and so it as not surprising that observers and identifiers might erroneously identify a specimen as C. involucrata. Also, C. involucrata would most likely have been included in the earliest Computer Vision models due to the number of observations, and it, along with C. pedata may have been the only two Callirhoe suggested by the iNaturalist system.

The second trend is that the species most commonly misidentified was C. leiocarpa. It is difficult to determine the ultimate cause of why C. leiocarpa was misidentified so often, but at least two reasons seem possible. First, though I have not examined the data in detail, it is clear that the range of C. leiocarpa seems to be expanding, and numerous observations of it occurred around major metropolitan areas like Dallas, Fort Worth, and Houston, all areas where it was thought not to occur previously (Dorr 1990). It seems plausible that naturalists in those areas were not familiar with C. leiocarpa and were thus identifying it as other species such as C. involucrata and C. pedata. In addition to that, it is likely that C. leiocarpa was not included in the earliest versions of the Computer Vision model on iNaturalist, so that it would not have occurred as a suggestion by the iNaturalist system and observers and identifiers may not have even known it was a possibility. More research might reveal the answer.

Most commonly assigned species in incorrect identifications
Species Times used as incorrect ID
C. involucrata 247
C. pedata 35
C. alcaeoides 6
C. leiocarpa 2
C. papaver 0
Total 290

Most Common Misidentifications where species could be identified
Actual Species Identified as Occurences
C. leiocarpa C. involucrata 95
C. leiocarpa C. pedata 18
C. pedata C. involucrata 18
C. papaver C. involucrata 10
C. involucrata C. alcaeoides 3
C. alcaeoides C. pedata 2
C. involucrata C. pedata 2
C. pedata C. leiocarpa 2
C. papaver C. pedata 1
Total 151

As stated above, in many cases there is enough information to disprove the identification but not enough to prove which other species the specimen is. The most common case of this occurring is when a specimen is identified as C. involucrata but it has a valvate bud or lacks an involucel. I suspect the vast majority of these cases are C. leiocarpa, with a minority of them being C. pedata and a few being C. papaver, as is the case with those which can be identified to species, but I have not attempted a rigorous analysis of this set of observations.

Most commonly assigned species in incorrect identifications where species could not be identified
Species Times used as incorrect ID
C. involucrata 124
C. pedata 11
C. alcaeoides 3
C. leiocarpa 1
C. papaver 0
Total 139


There does appear to be a significant error rate for the data examined, and it seems plausible that a similar error rate may have continued without some intervention. The difference in the years could be attributable to any number of factors such as differences in the dataset itself and differences in the iNaturalist observer and identifier community. A significant portion of these errors seems to be attributable to ignorance of C. leiocarpa, and perhaps this could at least partially be rectified by simply correcting the erroneous identifications, which I plan to do. There could however be a significant number of erroneous identifications in the data for other years, which I have not examined rigorously. I have also created a guide, "A short Guide to Callirhoe in Texas", as a starting point to help the iNaturalist community better identify Callirhoe specimens in the future. Hopefully, some difference will be made by identifications that have already been corrected. Additionally, updates to the iNaturalist Computer Vision system may already be helping the issue. Four of the six Texas species (including C. leiocarpa) are now included in the iNaturalist Computer Vision model, though one somewhat common species,C. papaver, is still excluded. It will likely be included in future models as there are almost enough observations to meet the previous criteria to be included in the models.

The question of what to do with the large number of Research Grade observations which do not appear to have enough evidence to support a species level identification remains unanswered. There may be incorrect identifications among them which might raise the error rate, but I suspect the majority of them probably are in fact C. involucrata. However, it would be nice to have some middle ground between Needs ID and Research Grade to indicate that they may be likely to be C. involucrata but that there is not enough proof to fully support that claim. This is an issue with iNaturalist itself though and there does not appear to be any solution on the horizon as far as I can tell.


Diggs, G. M., Lipscomb, B. L., O'Kennon, B., Mahler, W. F., & Shinners, L. H. (1999). Shinners & Mahler's Illustrated Flora of North Central Texas. Botanical Research Institute of Texas.
Dorr, L. J. 1990. A Revision of the North American genus Callirhoe (Malvaceae). Mem. New York Bot. Gard. 56: 1–75.
Dorr, L. J. 2015. Callirhoe. In: Flora of North America Editorial Committee, eds. 1993+. Flora of North America North of Mexico. 20+ vols. New York and Oxford. Vol. 6. http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=105128
Enquist, Marshall. 1987. Wildflowers of the Texas Hill Country. Lone Star Botanical, Austin, Texas.
iNaturalist. Available from https://www.inaturalist.org. Accessed [2021].
Kartesz, J.T., The Biota of North America Program (BONAP). 2015. North American Plant Atlas. (http://bonap.net/napa). Chapel Hill, N.C. [maps generated from Kartesz, J.T. 2015. Floristic Synthesis of North America, Version 1.0. Biota of North America Program (BONAP). (in press)].
McDaniel, R.T. “A short Guide to Callirhoe in Texas.” iNaturalist, https://www.inaturalist.org/journal/rymcdaniel/54356-a-short-guide-to-callirhoe-in-texas. Accessed August 2021.


1.0 - September 1, 2021 - Original revision.

Publicado el septiembre 1, 2021 10:40 TARDE por rymcdaniel rymcdaniel | 5 comentarios | Deja un comentario

06 de agosto de 2021

A short guide to Callirhoe in Texas


The genus Callirhoe is a genus of mostly reddish and sometimes white flowering plants in the Malvaceae family native to North America. The most recent study of the genus was by Dorr in A Revision of the North American Genus Callirhoe (Malvaceae) published in 1990 and revised for the Flora of North America (FNA) in 2015. Of the nine species in the genus, six species are found in Texas, five of which have observations on iNaturalist with the sixth being a rare endemic found in only a few counties of the southern Rolling Plains. A seventh species occurs in Oklahoma along the Texas border in southeast Oklahoma.

The reason for providing this short guide is to educate iNaturalist observers and identifiers about the ways to identify the different species in Texas. In the spring of 2021, I began checking various research grade observations and noticed a significant number of incorrect observations. At that point I decided to perform a more rigorous examination of research grade(RG) observations, starting with RG observations from Texas for the year 2019 which I had not already identified as the initial data set. Preliminary results indicate that as high as 19.6% (168 of 856) of those observations were misidentified. While I plan to explore those results and others in a future post, it became clear that an article illustrating some of the concepts used in identification might be helpful for the iNaturalist community.

Species in Texas

A mentioned in the introduction, six species of Callirhoe occur in Texas. Relatively accurate distribution maps for these species can be found on the Biota of North America Program (BONAP) website, though the distribution of one species, C. leiocarpa maybe somewhat erroneous and currently seems to be in flux. The six species as ordered by their prevalence on iNaturalist are (vegetation areas as found in Shinners & Mahler's Illustrated Flora of North Central Texas (1999) (FNCT) :

  • C. involucrata: The most widespread of all Callirhoe species, it occurs throughout most of Texas, except for part of the Trans-Pecos in west Texas and parts of northeast Texas where it gives way to C. papaver.
  • C. pedata: Occurs in central and north central Texas from the Edwards Plateau north to the Oklahoma border in the Cross Timbers and Prairies and Blackland Prairies
  • C. leiocarpa: Historically occurred in central and south central Texas from the Edwards Plateau south to the Gulf Coast in the South Texas Plains and Gulf Prairies and Marshes. Recent iNaturalist observations have placed it in additional areas, typically around the major metropolitan areas of Houston, Dallas, and Fort Worth, where it was not found before
  • C. alcaeoides: Restricted to the northern sections of the Cross Timbers and Prairies and Blackland Prairies, starting just south of the DFW area and running northward into Oklahoma
  • C. papaver: In east and southeast Texas, primarily in the Piney Woods and Gulf Coast Prairies and marshes possibly into Post Oak Savannah and Blackland Prairies
  • C. scabriscula: A rare endemic known from only a few counties along the Colorado River in the Rolling Plains. It has not been observed on iNaturalist as of this time and I will not discuss it in detail.

A seventh species, C. bushii, occurs in southeast Oklahoma along the border with Texas. It has not been found in Texas, though it seems plausible that it might occur along the Red River in northeast Texas. One notable exception to this list is C. digitata, which is no longer treated as being found in Texas. Earlier generic treatments apparently included the species now known as C. pedata within the species concept of C. digitata, but that is no longer the case. C. digitata is now only known to be found outside Texas in states like Arkansas, Oklahoma and Missouri, though BONAP maps do show them close to the Oklahoma Texas border. The last species, C. triangulata, is found outside of Texas, primarily in Illinois and Wisconsin but also sporadically in the southeast.


Identification of the different species of Callirhoe in Texas is not difficult if the appropriate features are photographed. Of course, as with many species on iNaturalist, this is the problem. A significant percentage of Callirhoe observations consist of one or maybe two photos of the flower, which generally is not sufficient for a high confidence identification, at least not one based on the morphological features.

Keys to the genus can be found in both the Flora of North America online (efloras) and also in the Flora of North Central Texas (omitting C. papaver and C. scabriscula), which is also available online at the BRIT website. The reader can reference those keys; I will try to illustrate some of the important differentiating features found in them below. While corolla color can be helpful, some other important features are the buds, the involucel, the stipules, the fruit, the inflorescence and the sepal hairs.

Useful features for identification of common Callirhoe species in Texas
Species Petal
Involucel Buds
Large Beaked
C. involucrata reddish purple basally white, white, white with reddish vertical stripes yes no - no long simple
C. papaver reddish purple usually yes - no long simple
C. leiocarpa reddish purple basally white no yes yes yes glabrous
C. pedata reddish purple to purple basally white or lightened, white, rarely pink no yes no no mostly glabrous
C. alcaeoides white to light pink no yes - yes short simple

Petal color

Callirhoe in Texas are predominately reddish purple in color, though white species and forms also occur as well as more rare pink ones. The reddish purple ones range from a reddish purple to purple, often within each species. All species in Texas have a red purple form except for C. alcaeoides, though it can appear light pink. Almost all red species of Callirhoe in Texas can have some lightening of the color near the base of the petals, which can sometimes be completely white. This is sometimes referred to as a basal spot. Typically C. involucrata has a basal spot, often larger than in other species. C. leiocarpa generally has a smaller basal spot, while C. pedata and C. papaver often have a mild lightening of color, rarely completely white. Given the variation of this feature, it cannot be used as a diagnostic feature on its own, but is sometimes helpful in conjunction with other features. The literature indicates that C. pedata does not have a basal spot, but it seems specimens on iNaturalist apparently do (TBD).

Red forms of Callirhoe: C. involucrata, C. leiocarpa, C. pedata (C. papaver not pictured)

Three species of Callirhoe have white or light colored forms. C. alcaeoides is predominately white but sometimes light pink. Two of the predominately reddish species, C. pedata and C. involucrata have light forms, which are often initially identified incorrectly as C. alcaeoides. Like C. alcaeoides, the mostly reddish purple C. pedata can also be white and rarely light pink, with all three colors sometimes occurring in the same population. Light forms of C. involucrata also occur, chiefly in areas of central Texas. In Williamson county, a white form with variable large reddish vertical stripes is the predominant form, and it is probably the only one which can be identified on the basis of the corolla color alone. White color forms also occur on parts of the Edwards Plateau such as Kimble and Menard counties (Enquist 1987).

Light forms of Callirhoe: C. alcaeoides, C. pedata, C. involucrata, C. involucrata var. lineariloba (see discussion on varieties)


The Flora of North America(FNA) key for Callirhoe starts with the presence or absence of the involucel, which for Callirhoe consists of a whorl of bracts (usually three, sometimes one) subtending the sepals. This feature separates the species into those with an involucel (C. involucrata, C. papaver, C. scabriscula, and C. bushii) and those without (C. pedata, C. leiocarpa, C. alcaeoides). The involucel is most easily visible on the buds, but can also been seen, sometimes with greater difficulty due to proximity of the sepals, on open flowers and fruiting heads. In many parts of Texas, C. involucrata is the only species with an involucel and a somewhat confident identification can be made based on the presence of that feature. Where C. involucrata comes in contact with other species that have an involucel (in Texas mostly C. papaver in east and southeast Texas but also potentially northeast Texas close to C. bushii) other features need to be used for identification, such as the bud (see next section).

C. involucrata with an involucel (other species not pictured)

In treatments previous to Dorr, the spacing between the involucellar bracts and the base of the calyx was sometimes used to differentiate C. involucrata and C. papaver, with that space being larger in C. papaver than C. involucrata. However, according to Dorr (1990), though this is generally true, it is apparently not always consistent or clear, so he uses the buds to differentiate the two species.

There is some variation in the size and shape of involucel bracts. Outside of Texas, this variation is useful for differentiation of various species such as C. papaver,C. bushii, and C. triangulata. Within Texas, the variation is one of the characters used in differentiation of the varieties of C. involucrata.

Species without an involucel C. leiocarpa, C. pedata, C. alcaeoides


The bud is a useful feature to capture for identification of Callirhoe in Texas, though it is rarely photographed on purpose. Buds in C. involucrata are unique among Callirhoe in that the tips of the sepals/calyx lobes do not come together to form a point; there is always at least some small amount of visible separation. When the calyx lobes do come together in the bud, the bud is called valvate and all Callirhoe species besides C. involucrata have valvate buds. The FNA key only uses this feature to differentiate C. involucrata from other species with involucels, but it can be used to differentiate C. involucrata from all other Callirhoe species. The presence of a non-valvate bud provides evidence that the specimen is C. involucrata whereas the presence of a valvate bud rules out as a C. involucrata possibility.

An added benefit of capturing the bud is that the presence or absence of an involucel is often more obvious on buds than on flowers.

Non-valvate bud of C. involucrata with sepal tips widely separated

Valvate bud of C. leiocarpa and C. alcaeoides with sepal tips coming together


The stipules (leaf like appendages at the base of the leaf petioles) are useful for distinguishing two of the taller species in Texas, C. leiocarpa and C. pedata, which are somewhat similar in their lack of involucel and typically erect or ascending habit. C. leiocarpa has auriculate stipules whereas C. pedata does not. This feature needs to be used with other features for identication such as the absence of an involucel, as C. involucrata can have somewhat auriculate stipules as well. Though this differentiating character was included in Dorr's original treatment, it was not included in the key for Callirhoe in the Shinners & Mahler's Illustrated Flora of North Central Texas, which references Dorr's work. It is possible that is not completely definitive as I have seen some examples of C. pedata with small projections at the stipule base, but it does generally seem to be true and is present in Dorr's FNA key. The auriculate stipules of C. leiocarpa are often noticeable even from a distance and in blurry photographs. This may be because their inner face (adaxial) tends to spread away from the stem and face upward like a sessile leaf or because the auricles often encircle much of the stem.

C. leiocarpa stipules

C. pedata stipule


The fruit is primarily helpful in distinguishing C. leiocarpa from other species in Texas due to its distinctive appearance. The fruit (shown in pictures below) is usually seen from above and visually has three distinct regions from this perspective: a whitish central column, a variable size greenish ring (appears to correspond to the beak), and lastly a variable size greenish yellow to white ring on the outside (which can correspond to the seed bearing portion or the collar depending on species). In C. leiocarpa, the green region (corresponding to the beak) is quite large compared to the encircling white ring (in this case a small projection called a collar which subtends the beak). Most other species in Texas, except C. alcaeoides, have a smaller green region in mature fruit (a smaller beak), similar to that shown in the C. pedata example below. Note however, that C. pedata is described as having a larger beak in areas outside of Texas, so the this difference may not apply there. Also note that immature fruit of C. pedata often have a large green area relative to the surrounding white area, so it is important to observe a mature fruit.

Fruit of C. leiocarpa, C. pedata

Inflorescence and Sepals Hairs - C. pedata and C. alcaeoides

Both C. pedata and C. alcaeoides are species without an involucel and both can have white corollas, which can make differentiation difficult in areas where they overlap as Dorr noted(1990). While the inflorescence of C. alcaeoides is typically more compact (Dorr's FNA key describes the racemes as "appearing corymbose or subumbellate"), it can be difficult to ascertain this in photos, especially in younger plants where the first open bloom may be close to unopened buds. The FNCT uses an additional character to differentiate the two species, the vestiture of the calyx. In C. alcaeoides it is described as "hispid-pubescent" and in C. pedata as glabrous or sparsely pubescent. Neither of Dorr's treatments use this as a differentiating character between the two species, though the species descriptions in his earlier work do seem to agree with this difference.

Early compact inflorescence of C. alcaeoides

Pubescent sepals of C. alcaeoides

Glabrous sepals of C. pedata

Varieties of C. involucrata

C. involucrata is described as having three varieties, two of which occur in Texas and which Dorr indicates are weakly separated(2015). The two which occur in Texas are C.i. var. involucrata and C.i. var. lineariloba. These two varieties are differentiated by qualities of the leaves, stipules, involucellar bracts and lastly, only partially sometimes, color. Determination of the variety for the most part requires close examination and measurement of these features, so it is typically not possible to make a variety determination based on photos alone. It is probably the case that most observations of C. involucrata in Texas are in fact C.i. var. lineariloba as attested to by Dorr's range maps(1990) for C. involucrata which show that C.i. var. lineariloba is found throughout much of Texas with C.i. var. involucrata apparently only occurring in a few areas in north central Texas, predominantly close to the Oklahoma border.

Some confusion exists around identification of C.i. var. lineariloba in central Texas where the variety has become associated only with the color form found mostly in Williamson county (sometimes referred to by locals as the "Williamson county winecup"), where the petals typically have a central broad vertical reddish purple region borded by white margins. I don't know if earlier research restricted the variety to this color form, but it is implicitly done in Marshall Enquist's popular Wildflowers of the Texas Hill Country (which predates Dorr's work). Ironically, though C.i. var. lineariloba probably mostly consists of reddish purple specimens, only this different color form is easily identifiable as C.i. var. lineariloba since it does not apparently occur in C.i. var. involucrata (or any other species of Callirhoe for that matter). Thus the misconception is perpetuated, but I don't see an easy way around it.

iNaturalist Observations

Observations used in the guide
Taxon Observation
Features Illustrated
C. alcaeoides 88741669 white color, lack of involucel, valvate bud, sepal pubescence
C. involucrata 80169982 red color
C. involucrata 78509404 white color
C. involucrata 50584755 involucel
C. involucrata 83043800 involucel
C. involucrata 78382364 bud
C. involucrata var. lineariloba 89098715 light color with reddish regions
C. leiocarpa 88464887 red color, lack of involucel, valvate bud, auriculate stipules, fruit
C. pedata 88721978 red color, glabrous sepals
C. pedata 88745685 white color, lack of involucel, fruit
C. pedata 89107758 non-auriculate stipule

Other useful Observations
Taxon Observation
Features Illustrated
C. papaver 34204774 involucel, bud


Diggs, G. M., Lipscomb, B. L., O'Kennon, B., Mahler, W. F., & Shinners, L. H. (1999). Shinners & Mahler's Illustrated Flora of North Central Texas. Botanical Research Institute of Texas.
Dorr, L. J. 1990. A Revision of the North American genus Callirhoe (Malvaceae). Mem. New York Bot. Gard. 56: 1–75.
Dorr, L. J. 2015. Callirhoe. In: Flora of North America Editorial Committee, eds. 1993+. Flora of North America North of Mexico. 20+ vols. New York and Oxford. Vol. 6. http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=105128
Enquist, Marshall. 1987. Wildflowers of the Texas Hill Country. Lone Star Botanical, Austin, Texas.
Kartesz, J.T., The Biota of North America Program (BONAP). 2015. North American Plant Atlas. (http://bonap.net/napa). Chapel Hill, N.C. [maps generated from Kartesz, J.T. 2015. Floristic Synthesis of North America, Version 1.0. Biota of North America Program (BONAP). (in press)].


All photos used in this post are the property of Ryan McDaniel, all rights reserved.


1.0 - August 6, 2021 - Original revision.

Publicado el agosto 6, 2021 07:14 TARDE por rymcdaniel rymcdaniel | 13 comentarios | Deja un comentario

05 de junio de 2020

Differentiation of Gutierrezia texana and Amphiachyris species in North Central Texas


Gutierrezia texana is often confused with two Amphiachyris species with which it is sympatric, Amphiachyris dracunculoides and Amphiachyris amoena, and they have historically sometimes been treated in the same genus. For whatever reason Amphiachyris dracunculoides seems to have become the default choice both in the minds of amateur botanists and for the algorithm on iNaturalist (apparently because the other two have not met the requirements to be included in any of the computer vision models as of yet). All three plants have similar small capitula with yellow ray and disc flowers. The branching patterns can also be similar and the sizes often overlap. Amphiachyris dracunculoides often has a distinctive appearance when it exhibits its classic rounded shape with heads in dense corymbiform arrays, while both Gutierrezia texana and Amphiachyris amoena typically have more open paniculiform arrays. However, variations in the number of capitula caused by any range of factors can cause the appearances to be similar enough to be easily confused. Due to these similarities, it is necessary to examine other details of the plants to make a correct identification.

Differentiation via the phyllaries

The most convenient way for observers to differentiate the two genera in north central Texas is by observation of the phyllaries. As noted in the Flora of North America treatment of Amphiachyris, Amphiachyris species have "abaxial nerves of the phyllaries without green borders." The result is that the phyllaries on Amphiachyris species appear to have a uniform color from edge to edge, and thus often appear wider than the phyllaries on Gutierrezia species. Unfortunately, the green nerve borders in Gutierrezia texana are not always present. They often do present as a narrow dark green band bordering the phyllary nerve for much of the length of the nerve, but many times it also only occurs at the phyllary tips or under some weather and seasonal variations it may not be noticeable at all. The overall result however is the edges of the phyllaries on G. texana are often difficult to discern at all, and at best the phyllaries actually look a lot narrower than they really are.

Phyllaries of Gutierrezia texana

Phyllaries of Amphiachyris amoena

Phyllaries of Amphiachyris dracunculoides

Differentiation via the pappus

The best way to differentiate the genera in Texas is to examine the pappus of the disc flowers. In Amphiachyris, the pappus of the disc flowers consists of a few noticeably long scales. A hand lens may be useful to see them more clearly, but they are often visible with the naked eye.

In contrast, on Gutierrezia texana the pappus on both ray and disc flowers is short or absent, often not noticeable at flowering time. It is most easily noticed on achenes, if one is lucky enough to find a specimen with some intact.

Corymbiform versus Paniculiform arrays

While these flowering patterns don't differentiate the genera, they can still be helpful for differentiating A. dracunculoides, which is corymbiform, from the other two species, which are paniculiform. A corymbiform array is one in which all the flowers (or in this case heads) appear to be roughly at the same level. Specimens like these appear flat topped or rounded. Paniculiform arrays are more difficult to describe, but in general the heads do not appear at the same level. In practice, this can be difficult to ascertain when a photo simply appears to be a mass of yellow flowers, but sometimes one is able to isolate a specific branch and see which description applies. More often than not one can see heads much further down on a branch, making it paniculiform, and ruling out A. dracunculoides.

Corymbiform A. dracunculoides - note how the heads are roughly the same level

Paniculiform G. texana - note how there are heads at various levels of the branches

Disc Flower Style Branch Appendage Length

According to Nesom, the disc flowers of Amphiachyris species are functionally staminate and he also notes that the style branch appendages are fused. What this means visually is that the style branches in Amphiachyris disc flowers (when exposed) appear quite short. On the other hand, this is not the case in G. texana, so if one happens to find a capitulum where the style branches are exposed, they appear quite long. While presence of these longer style branches on disc flowers is indicative of G. texana, its absence may simply indicate that no flowers are in that stage of pollination. Additionally, one has to be certain of looking at a disc flower and not a ray flower where both genera can have long style branches.

Longer style branches of G. texana, often forming sort of a loop

Habitat and Distribution

In my experience, in the Austin area (Travis, Williamson, and Burnet counties), G. texana is much more prevalent than either Amphiachyris species in areas accessible by the public, and is often weedy on the borders of hiking trails. Amphiachyris dracunculoides is more often found in grazed pastures. All three plants do occur in the general area.

Observation Links

Amphiachyris dracunculoides
Amphiachyris amoena
Gutierrezia texana
Russell Pfau's comparisons


Nesom, Guy L. 2006. Amphiachyris. In: Flora of North America Editorial Committee, eds. 1993+. Flora of North America North of Mexico. 20+ vols. New York and Oxford. Vol. 20. http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=101427
Nesom, Guy L. 2006. Gutierrezia. In: Flora of North America Editorial Committee, eds. 1993+. Flora of North America North of Mexico. 20+ vols. New York and Oxford. Vol. 20. http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=114211

Publicado el junio 5, 2020 10:41 TARDE por rymcdaniel rymcdaniel | 17 comentarios | Deja un comentario