Archivos de Diario para febrero 2024

03 de febrero de 2024

Finding Oxytropis nana

Image: Putative Oxytropis nana from Natrona Co., WY, observed by FrontRangeWildflowers: (© CC-BY-NC)

The Wyoming Locoweed (Oxytropis nana) is a rare species whose entire documented range is within the borders of Wyoming: (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:

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:

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?

Group I (similar to lagopus):

[Note: BONAP does not mention O. nana from Teton Co.:]

Group Ib (pods only, calyx inflated, fully enclosing pod):

[Note: this should be var. lagopus]

Group Ic (pods emergent from calyx):

[Note: this should be var. atropurpurea but not clear how to distinguish them from besseyi without flowers.]

Group II (similar to besseyi):

Group IIb (pods only):

[Compare also to Group Ic (see note there). Note: BONAP does not mention besseyi from Sublette Co.:]

Group III (similar to lambertii):

Group IV (similar to sericea):

Group IVb (sericea? high elevation plants of compact growth habit, with white or yellow flowers):

Publicado el 03 de febrero de 2024 a las 11:41 PM por matthias22 matthias22 | 12 comentarios | Deja un comentario