Cacti in Manitoba - time for a treasure hunt

yes there are cacti found in Manitoba - and more could be known about them. Let's start with what was known in Scoggans 1957 Flora of Manitoba...

Pincushion cacti were represented by a single species: Mamillaria vivipara (Nutt.) Haw. which we currently know in iNat as Escobaria vivipara (Spinystar). All the reports listed were from sandhills. Localities were Lauder, Grande Clariere, Oak Lake, Virden and Spruce Woods Forest Reserve. GBIF lists a single herbarium specimen collected near Routledge in 1959 still listed under Mamillaria and another eight specimens collected between 1950 and 1981. INat observations of this species in Manitoba range from 2009 to last year. If you are a long time observer of these plants and have notes and photos on these plants between 1981 and 2009, uploading them to iNat could help fill in the gap.

Flowering peaks in June. It seems they are found in sunny sandy areas in two general clusters - one stretching from north of Oak Lake down to the US border and the other around Spruce Woods Provincial Park. Probably there are a few other sites not yet documented that exist in the vicinity of the currently known locations in its preferred habitat. Perhaps these are not two separate clusters.

This species is considered Critically Imperiled in Manitoba.

Scoggan also listed two species of Opuntia....fragilis and polyacantha. Opuntia fragilis (Brittle Pricklypear) is reported from a dry granite shore near Falcon Lake and dry sandy prairie in Spruce Woods Forest Reserve. GBIF lists 28 specimens collected between 1945 and 2019. INat observations of this species in Manitoba range from 2010 to this spring.

Flowering peaks a little later than the Spinystar in July. It has been found in many of the same locations as the spinystar. It is also found along rivers in suitable habitat stretching away in both directions from the sandhills. Unlike the spinystar this species is also found outside the southwest corner of the province in the Whiteshell. There is some thought that this additional range may be due to first people's interest in the plant so looking in suitable habitat along known traditional routes may turn up additional plants.

This species is considered Apparently Secure in Manitoba.

Opuntia polyacantha (Plains Pricklypear) was included in Scoggan's Flora from seven reports. The localities were Morden, Oak Lake, Miniota, Aweme, Lauder, St. Lazare, and Millwood. Later authors have thought that these plants were really fragilis.

In a recent exchange with Derek Stephen Hollingshead, he suggested that the scientific community was interested in new observations of Plains Pricklypear in Manitoba. There is a possibility that there might be something lurking in the mass of fragilis populations that wasn't actually fragilis.

A single herbarium specimen of Plains Pricklypear was collected 27 June 1889 from Blind River Manitoba. Checking the Canadian Geographic Names Database that name is associated with a tributary of the Souris River near Melita Manitoba Derek plans to verify the identification of this specimen in person in the coming year.

Recently additional populations of Plains Pricklypear have been found in Ontario and in Minnesota. Plants in Manitoba seem like an increasingly likely possibility. Any plants that are located here may contribute to a better understanding of the distribution of Opuntia both now and in the past.

So once you find a pricklypear in the wild and if you have all the time in the world to document it, here's the list of the dream shots....
  1. the whole plant filling the entire frame.
  2. step back from the plant so that it is still visible but so are all its immediate surroundings (other plants, fencelines, shore lines , what have you)
  3. go closer so that two pads are filling the frame - bonus points if you have a ruler in the image
  4. go even closer and take enough images of one or more of the points where the spines are growing from. Identifiers would like to count the spines, judge how long they are (ruler is nice), and get a sense of their character
  5. if you have fruit, flowers or flower buds, an image with the flower/fruit filling the frame from above and from the side.

Take a moment and check that your location is accurate to within 10 metres and not at the nearest cell tower. I know this can be tricky in our patchy signal coverage - you can always go old school and make yourself a little sketch map and fix things when you get back to signal.

@derekstephenhollingshead go ahead and add anything you think is useful in the comments

Publicado el mayo 15, 2024 02:41 TARDE por marykrieger marykrieger


@hipstermama, @lauras111, @moragschonken, @friesen5000, @seafra more background on where things have been found before
the need for the 2 pad shot is that many keys focus on the shape of the joint between the pads so images that let identifiers get a goood look at that feature are helpful - revisiting your usual known locations and getting those more detailed images will also be useful for those from away who are trying to get a sense of what is normal in Opuntia in Manitoba @derekstephenhollingshead

Publicado por marykrieger hace alrededor de 1 mes

My great-grandfather, E.H. Moss, wrote Flora of Alberta (1959) and subsequently provided detailed descriptions for both Opuntia fragilis (Nutt.) Haw. and Opuntia polyacantha Haw. species.

Moss, E. H. 1959. Flora of Alberta. University of Toronto Press, Toronto, ON, 546 pp.

These species descriptions may be of use to Manitoban botanists and naturalists.

Publicado por derekstephenholli... hace alrededor de 1 mes

"O. polyacantha Haw.

Stems prostrate, forming mats or clumps, the segments orbicular, 5-12 cm long, strongly flattened, about 1 cm thick; areoles of mature segments about 1 cm apart, almost all armed with 5-9 straight spines; flowers bright yellow, fading to bronze tints, 4-7 cm broad. Dry prairie grassland and denuded areas.
Southern Alta. "

Publicado por derekstephenholli... hace alrededor de 1 mes

A more detailed species description as per Pinkava (2003

"Opuntia polyacantha Haw.

Description and distribution:

Low sprawling shrub with prostrate branches. ~5-50cm tall. Cladode joints are green and glabrous. Terminal joints not easily detached. Pads are elliptic, narrowly to broadly obovate, or circular. ~6-27cm in length, ~2-18cm in width. Between 4-14 areoles per diagonal cross-section of a given joint. Areoles are near circular, 3-6mm in diameter. Spines cover all areoles, 1-18 per areole. The largest between 4-9cm in length. Spreading, curling in all directions. Straight, erect, ascending or deflexed. Major spines vary from yellow, brown or grey. Reflexed to porrect, 1-5 per areole. Radial spines are white to white-gray. Deflexed with 5-11 per areole. Glochids are yellow, age brown. At areoles apex, 1-5mm long. Flowers inner tepals range from yellow to magenta. Filaments are white, yellow to magenta. Style white to pale pink; stigma green. Fruits are tan to brown. Dry at maturity. 1.5-4.5cm long, 1.2-2.5cm in diameter. Areoles 10-33. 3-16 spines at each or only the upmost situated. 4-20mm long."

Publicado por derekstephenholli... hace alrededor de 1 mes

added an additional point on the image list for a closeup of the areoles - the places where the spines emerge from the plant

Publicado por marykrieger hace alrededor de 1 mes

One last thing thing I would like to share:

Hollingshead, D. S. (2024, February 12). The Importance of Studying Disjunct, Northeastern Opuntia (Cactaceae) Distributions and Populations:. iNaturalist.

Publicado por derekstephenholli... hace alrededor de 1 mes

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