Finding Oxytropis nana
Image: Putative Oxytropis nana from Natrona Co., WY, observed by FrontRangeWildflowers: https://www.inaturalist.org/observations/151764972 (© CC-BY-NC)
The Wyoming Locoweed (Oxytropis nana) is a rare species whose entire documented range is within the borders of Wyoming: https://bonap.net/MapGallery/County/Oxytropis%20nana.png (see also the 2023 Fabaceae Volume of Flora of North America).
Welsh (in FNA, 2023) describes the species as intermediate between Oxytropis sericea and O. multiceps. It also closely resembles O. lagopus. In both species (except var. conjugans of lagopus, which does not occur in Wyoming) the pods remain fully enclosed in the accrescent calyx. Welsh (2023) does not provide any diagnostic features for flowering plants which makes it very difficult to ID observations here on iNaturalist (most of which are made in the flowering stage).
Oxytropis nana herbarium specimens on SEINet: https://www.swbiodiversity.org/seinet/taxa/index.php?tid=93440&taxauthid=1&clid=0
Welsh's (2023) description: [to be added]
I have done my fair share of Oxytropis identifications on iNaturalist and have become familiar with a few species, but I am not an expert by any stretch. Oxytropis nana is completely unfamiliar to me but my hope is that the community might figure out a way to characterize this species based on photographs. I am therefore inviting everybody who is interested in Oxytropis to participate and share their insights.
As a first step I have assembled all observations that have at least one active O. nana ID. Many are sitting at genus or tribe level because they have other, conflicting IDs. I also added a couple of observations that have no nana ID but might be relevant. Some are from outside Wyoming and therefore likely misidentified, but I have included them here to give them fair consideration. When I assembled this list, I noticed that the IDs are very heterogenus (not surprising for a poorly known species). I therefore sorted them into morphological groups. The characters used for that are mentioned in my previous blog post on Oxytropis besseyi and related species: https://www.inaturalist.org/journal/matthias22/89224-identification-of-oxytropis-besseyi-lagopus-and-similar-species
Based on this, I was able to categorize observations with Oxytropis nana IDs into roughly five groups. My impression is that probably less than a handful are true nana, all the others resemble other species and are likely misdentified. However, it is also possible that O. nana simply can't be distinguished from other species except by fruit. In this case, I would expect that true nana are most likely found within Group I (lagopus lookalikes) and perhaps Group IV (oddball sericea-like plants with villous calyces).
Below are my groups. If you would like to participate in this review let me know what species each group represents, and let me know if I misplaced any observations. Also let me know about any observations I might have missed. Thanks in advance for your help!
True nana?
- https://www.inaturalist.org/observations/151764972 (Natrona Co., corolla pink)
- https://www.inaturalist.org/observations/151764693 (Natrona Co., corolla white)
- https://www.inaturalist.org/observations/198531388 (Natrona Co., corolla purplish pink)
- https://www.inaturalist.org/observations/198531569 (Natrona Co., corolla pink)
- https://www.inaturalist.org/observations/198531299 (Natrona Co., corolla pink)
- https://www.inaturalist.org/observations/167293521 (Converse Co., corolla pink-red)
- https://www.inaturalist.org/observations/6487888 (Carbon Co., corolla white, keel purple)
- https://www.inaturalist.org/observations/6330035 (Sweetwater Co., corolla white)
https://www.inaturalist.org/observations/83458215 (Fremont Co., new)
Oddball:- https://www.inaturalist.org/observations/6487883 (Natrona Co., corolla pink-red)
Group I (similar to lagopus):
[Note: BONAP does not mention O. nana from Teton Co.: https://bonap.net/MapGallery/County/Oxytropis%20nana.png]
- https://www.inaturalist.org/observations/81929382 (Teton Co.)
- https://www.inaturalist.org/observations/12665746 (Teton Co.)
- https://www.inaturalist.org/observations/47365734 (Teton Co.)
- https://www.inaturalist.org/observations/12665746 (Teton Co.)
- https://www.inaturalist.org/observations/81929382 (Teton Co.)
- https://www.inaturalist.org/observations/170527431 (Park or Teton Co.)
- https://www.inaturalist.org/observations/752728 (Park Co.)
- https://www.inaturalist.org/observations/171220042 (Park Co.)
- https://www.inaturalist.org/observations/167965739 (Sheridan Co.)
- https://www.inaturalist.org/observations/120773364 (Albany Co.)
https://www.inaturalist.org/observations/6364646 (Albany Co., new)
Montana observations (outside of documented range):- https://www.inaturalist.org/observations/77944298
- https://www.inaturalist.org/observations/82923061
- https://www.inaturalist.org/observations/84939548
Group Ib (pods only, calyx inflated, fully enclosing pod):
[Note: this should be var. lagopus]
https://www.inaturalist.org/observations/123774186 (Teton Co.)
Not from Wyoming (outside of documented range):- https://www.inaturalist.org/observations/125258804 (Montana)
- https://www.inaturalist.org/observations/49666108 (Idaho)
Group Ic (pods emergent from calyx):
[Note: this should be var. atropurpurea but not clear how to distinguish them from besseyi without flowers.]
- https://www.inaturalist.org/observations/80160935 (Albany Co.)
- https://www.inaturalist.org/observations/6351786 (Carbon Co.)
- https://www.inaturalist.org/observations/6344643 (Carbon Co.)
Group II (similar to besseyi):
- https://www.inaturalist.org/observations/187691541 (Park Co.)
- https://www.inaturalist.org/observations/187683735 (Park Co.)
- https://www.inaturalist.org/observations/174748423 (Park Co.)
- https://www.inaturalist.org/observations/125246654 (Park Co.)
- https://www.inaturalist.org/observations/167314358 (Park Co.)
- https://www.inaturalist.org/observations/167313687 (Park Co.)
- https://www.inaturalist.org/observations/115777369 (Park Co.)
- https://www.inaturalist.org/observations/173362994 (Park Co.)
- https://www.inaturalist.org/observations/175658307 (Hot Springs Co.)
- https://www.inaturalist.org/observations/124414864 (Fremont Co.)
- https://www.inaturalist.org/observations/124070420 (Fremont Co.)
- https://www.inaturalist.org/observations/88081309 (Fremont Co.)
- https://www.inaturalist.org/observations/51824386 (Fremont Co, flowers not fully open)
- https://www.inaturalist.org/observations/173872532 (Fremont Co., not sure about this one)
Group IIb (pods only):
[Compare also to Group Ic (see note there). Note: BONAP does not mention besseyi from Sublette Co.: https://bonap.net/MapGallery/County/Oxytropis%20besseyi.png]
- https://www.inaturalist.org/observations/121284045 (Fremont Co.)
- https://www.inaturalist.org/observations/169888773 (Sublette Co.)
Group III (similar to lambertii):
- https://www.inaturalist.org/observations/6487866 (oddball, habitus like lambertii but calyx villous and wing petals more spreading)
Group IV (similar to sericea):
- https://www.inaturalist.org/observations/171220052 (Park Co.)
- https://www.inaturalist.org/observations/170385937 (Big Horn Co.)
- https://www.inaturalist.org/observations/80273913 (Big Horn Co.)
- https://www.inaturalist.org/observations/80795589 (Fremont Co.)
- https://www.inaturalist.org/observations/120263496 (Fremont Co.)
- https://www.inaturalist.org/observations/122104942 (Fremont Co.)
https://www.inaturalist.org/observations/168749468 (Sweetwater Co.)
Not from Wyoming (outside of documented range):- https://www.inaturalist.org/observations/84927057 (Montana)
- https://www.inaturalist.org/observations/102972776 (Montana)
- https://www.inaturalist.org/observations/184878110 (Idaho)
Group IVb (sericea? high elevation plants of compact growth habit, with white or yellow flowers):
- https://www.inaturalist.org/observations/86906526 (Sublette Co.)
- https://www.inaturalist.org/observations/173326038 (Montana, outside of documented range)
