Malva in Califorina
So far, this is just a very rough post for scrawling some notes while chatting about Malva with @truthseqr .
On Malva multiflora (vs nicaensis):
- M. mutiflora is a newly resurrected epithet. Most of the literature has it as M. pseudolavatera, or M. cretica, or Lavatera cretica.
- Butler and Reinders (2021) has great photos (thanks for the link @truthseqr ). In particular, they show a distinct difference between the fruits (schizocarps and mericarps) of M. multiflora and M. nicaensis. I spent a little time trying to find a more authoritative botanical illustration of the way multiflora has those rounded mericarps. I haven't come up with much on that yet, other than what can be read in text descriptions.
- A genetic study places multiflora right next to nicaensis (Forbes Ray 1995)
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The Wayne's World site by @mrwolffia has great photos of key structures in the genus, and evidence for an undescribed California taxon between multiflora/pseudolavatera and nicaensis.
https://www.waynesword.net/traug99d.htm - For keying Malva in California, I thinkTJM is easiest and clearest (https://ucjeps.berkeley.edu/eflora/eflora_keys.php?key=9580). But I think FNA has better species descriptions -e.g. for things like the ridges on mericarps (http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=119571)
Comments
@fredwatson, this is great info. Could you please copy this info to the project journal for Malvas in CA?
https://www.inaturalist.org/projects/malva-california/journal
Sure. Would you like me to just copy a link to my journal entry here (which is like to evolve as a learn more), or copy the actual content across?
It would be nice to have the updates as you make them. So, perhaps you could post a link (or make the project journal your primary text).
Thanks for helping to figure out these IDs. The many different keys are confusing to me. I'd like to help educate folks (and myself) how to take photos for the purpose of identification, so we don't have so many unidentified or incorrectly identified Malvas in iNat.
As I go through the observations in CA, I find it challenging to differentiate M. nicaeensis from M. multiflora. I'm curious why the keys make this differentiation so hard. I first look for the epicalyx segments (are they joined or not?), but sometimes the hairiness of this area makes it hard to see. I also look at the fruits. For me, that's the easiest way to differentiate these two species. And spent flowers can help with the ID: M. nicaeensis flowers dry blue; M. multiflora flowers dry brown.
The Wayne's World reference state:" Petals of M. pseudolavatera are 15 mm long, but this is an upright shrubby plant, not at all decumbent." But I've found many examples of decumbent M. multiflora. Here are a few:
https://www.inaturalist.org/observations/189391432
https://www.inaturalist.org/observations/116337421
eJepson states that M. multiflora is uncommon and found in disturbed places on coastal bluffs, dunes, occasionally inland. But M. multiflora is very common in the SF Bay Area. I see it everywhere I hike, both around the south bay and in the hills.
Agreed. The keys differ enough to make this hard. In part I think this because the characters have not been sufficiently distinguished. For example, Ahmad et al. (2022) refer to parviflora and neglecta as being "morphologically identical" in their abstract, but then go on to list apparent differences in Table 1 of their paper.
Also tricky to figure out is that the different terminology used in TJM2, FNA, and the broader literature e.g.:
"Epicalyx segments" versus "Involucellar bractlets"
"Connate" / "adnate" / "distinct" versus "Fused to each other" and "free"
There are synonyms to an extent here, but it is perhaps not obvious to disern where distinct become connate (and where adnate fits within that scale) and where free becomes fused, and whether this happens at the same point under both terminologies.
Another discrepancy I saw was in the Jepson description for M.parviflora that said it's max height is 2 ft, yet I saw one last spring that was shoulder height (4 ft):
https://www.inaturalist.org/observations/152057854
There are two easy ways to separate M. nicaeensis from M. multiflora (including the procumbent form) beyond what we put in the guide:
The epicalyx segments/involucellar bractlets are separate from each other, but are very often not attached to the pedicel in the normal way for the small mallows, but rather fused to the base of the calyx. Both of your keys note this, but we chose not to include it for simplicity's sake, and because it is not consistent; but if you find this characteristic fusion (which you normally should) then you can ID M. nicaeensis based on the epicalyx alone! Also, very good photos are needed to distinguish the point of attachment. This https://inaturalist.nz/observations/57428155 shows the fusion reasonably well.
The stem hairs are mostly single and have highly characteristic tubercles at their bases, so you can also ID M. nicaeensis with complete ease from only a stem! No floras or keys mention this, so we didn't include it, but so far I have found this to be without exception true. I'll check some Californian observations to see whether it holds true there also. (In contrast, M. multiflora hairs are mostly stellate, and do not arise from tubercles). I came across these M. nicaeensis just yesterday which have unusually developed tubercles: https://inaturalist.nz/observations/193851479.
And another couple of examples: https://inaturalist.nz/observations/63870728
https://inaturalist.nz/observations/36052951
Many thanks @reinderw!
Re: epicalyx segments. I think I've been noting them correctly. Here's a couple of observations that have my best photos of that particular character:
https://www.inaturalist.org/observations/180714770
https://www.inaturalist.org/observations/183551546
And here's one with a good photo, but with a more marginal ID:
https://www.inaturalist.org/observations/187712689
Re: stem hairs. This is something I hadn't yet noticed in the keys. But I see now that it is mentioned in the species descriptions in Flora of North America, with nicaensis being "both simple and stellate" and multiflora (pseudolavatera) being "sparsely stellate-hairy" (http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=119571). Just checking back through some of my "nicaensis" observations, I think I found at least one (with a good photo of the hairs) that has predominantly stellate hairs but for which my initial ID was uncertain:
https://www.inaturalist.org/observations/107457061
You've got it. I've IDed and commented on your observations!
Thanks :)
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