Plant genus Lasiopogon Cass. (Asteraceae: Gnaphalieae) new to North America

This is one of the many reasons I love iNaturalist.

About 4 years ago I started noticing some unusual "Gnaphalium palustre" observations from southern Arizona (plus one so far from southern California). I gave them that identification as a "best fit," but with reservations often expressed in the comments. [EDIT 3/2022: the original southern California suspect turns out to be Gamochaeta stagnalis, but now there is a new and better candidate.]

Seeing another one yesterday was my last straw, and I decided to pull out all stops to see if a better name could be found for these plants. It was increasingly apparent that these plants are not Gnaphalium palustre, nor anything else known in the Arizona or California floras.

So what was my first go-to for doing further research? Why, iNaturalist of course! Using the Compare feature on the most recent observation, I first looked through all the Asteraceae tribe Gnaphalieae observed or listed for North America, doing Google image searches for taxa that didn't have photos in iNaturalist. (And of course, also taking the iNaturalist photos with the appropriate grain of salt too.) Nothing else in North America was close to a match.

Next, knowing where Gnaphalieae tend to be more diverse, I did the same search in Australia. Still nothing. Next was Africa. Bingo! Some iNaturalist photos associated with Lasiopogon observations from southern Africa showed exactly the same distinctive head apices I had been noticing in the North American observations, and the rest of the plants were matching also.

The relevant North American observations are now here -- if the page comes up blank, wait a few moments for it to populate. It's using a special URL that slows it down. (Caution all, when adding identifications, it's easy to accidentally add the fly genus Lasiopogon instead of the plant genus!)

@ngb
@tonyrebelo
@botaneek
@fragmansapir
@kai_schablewski

can you have a look through the observations linked in the paragraph above, and see if it's possible to identify the species for any of them? Based on existing geographic range, the most likely candidate for introduction to North America would be Lasiopogon muscoides. The RG Lasiopogon observations on iNaturalist, however, seem to show two different things under this name, one with shorter, fuzzier, and denser leaves than the other (the other looking more like the North American plants). And there is also a Lasiopogon brachypterus observation looking pretty similar to the North American plants.

At least judging from the records on SEINet and the California Consortium, no North American specimens have yet been identified as Lasiopogon. [UPDATE 2020-10-15: two specimens have now been uncovered at ASU.] Considering that, plus the fact that iNaturalist observations didn't start showing up until about 4 years ago, and that they are concentrated in disturbed habitats around the Phoenix and Tucson metro areas, suggests that this might be a fairly recent introduction (and possibly the first in the Western Hemisphere). If so, it has already spread pretty rapidly. But there could also be older records that have been fooling North American plant taxonomists until now.

In any case, there are likely Lasiopogon specimens in Arizona and other herbaria at this point that are misidentified as Gnaphalium or other Gnaphalieae. And there are likely more iNat observations of it waiting to be surfaced, most likely here, and possibly a few here and here. Heads up @aspidoscelis @dhwilken @gentilcore @jrebman @rojosmojo @sabra2 @stevejones -- and please @ tag (in a comment below) any other inatters who work with regional herbaria, or could help identify Lasiopogon to species level.

UPDATE 8 April 2022: new report now published for Lasiopogon glomerulatus.

Posted by jdmore jdmore, September 21, 2020 00:16

Comments

Posted by ethan-k almost 2 years ago (Flag)

Very interesting! Can you provide a key couplet, character description, or external source for how to distinguish Lasiopogon from Gnaphalium?

Posted by tmessick almost 2 years ago (Flag)

@emaking
@danikasetaro (re:this observation)
Great detective work, Jim!

Posted by stevejones almost 2 years ago (Flag)

@tmessick good question. My first thought would be the print version of Flora Europaea from the 1970s, but that doesn't seem to be online in any form or fashion that I can find. Maybe others reading this post will have a better suggestion.

Posted by jdmore almost 2 years ago (Flag)

This is what Flora Europaea (volume 4) has on Lasiopogon:

Posted by ethan-k almost 2 years ago (Flag)

There's also this, in Google Books, and if you're lucky it will show you page 249:
https://books.google.com/books?id=VhUZnM8S47IC&pg=PA249#v=onepage&q&f=false
But it's a bracketed key with just one character per couplet — nice if you're a computer, but much harder for me (and I think most other humans) to use than a key that's indented, describing 2 or more character states where possible.
Lasiopogon is described on page 269 of the above-linked book (Flowering Plants. Eudicots: Asterales. edited by Joachim W. Kadereit, Charles Jeffrey. Springer Science & Business Media, Jul 12, 2007).
P.S.: This key to Gnaphalieae in Flora of Pakistan might be helpful:
http://www.efloras.org/florataxon.aspx?flora_id=5&taxon_id=20582
The stereomes (supportive sclerenchyma at the base of the phyllaries) being divided (as in Lasiopogon) vs. undivided (as in Gnaphalium) seems to be relevant.
P.P.S.: And then there's this, about some taxa segragated from Lasiopogon (not sure if the distinction is still recognized): https://archive.org/details/journalofsouthaf30unse/page/52/mode/2up?q=Lasiopogon

Posted by tmessick almost 2 years ago (Flag)

Thanks @odandno and @tmessick, very helpful. I was able to see the Google Books key through page 251, where Lasiopogon et al. are keyed against Gnaphalium et al. (Was able to see the Lasiopogon description also, but not the Gnaphalium description for comparison.)

I also found this SANBI key with linked descriptions. Combining all the above gives me this so far:

Lasiopogon: capitula closely surrounded by leaves, massed in glomerules at branchlet tips; phyllary stereome conspicuously divided; pappus plumose or barbellate.

Gnaphalium: capitula few together, rarely solitary, sometimes surrounded by whorl of leaves; phyllary stereome undivided; pappus barbellate.

(The stereome is the thicker, herbaceous or cartilaginous portion of a phyllary, proximal to the thinner apical lamina or flag.)

Posted by jdmore almost 2 years ago (Flag)

I hope you'll be collecting herbarium specimens and depositing them in herbaria in your area. This needs as much documentation as possible. Great detective work to solve this mystery!

Posted by sedgequeen almost 2 years ago (Flag)

There may already be some, Barbara - I made this collection in 2012, and this morning mentioned it to Liz Makings at ASU. Wouldn't be surprised if there are others in the Gnaphalium palustre folder there.

Posted by stevejones almost 2 years ago (Flag)

What an interesting discovery! Thank you, Jim, for figuring this out. And thanks to everyone for all the supporting information. Something for us to be looking for in the desert areas of Eastern CA.

Posted by ahowald395 almost 2 years ago (Flag)

Great! (I'm pretty herbarium oriented, so like to make sure they aren't forgotten.)

Posted by sedgequeen almost 2 years ago (Flag)

@stevejones, that specimen kinda looks like actual Gnaphalium palustre, as best I can tell from its image.

Posted by jdmore almost 2 years ago (Flag)

Good - thanks for checking it. My [insert expletive of your choice here] cataracts are giving me trouble with close work these days and I wasn't sure. Hopefully Liz can confirm. If it ever rains again here we can look for Lasiopogon some more.

Posted by stevejones almost 2 years ago (Flag)

Thanks for the heads up Jim. This will be important for us to bring up in the iMapInvasives/EDDMaps world. If it is moving quickly, I can also bring it to the attention of the Western Governors Association Invasive Species Council.

Posted by sabra2 almost 2 years ago (Flag)

@sabra2 yeah, this is going to be a tough one because of how similar its appearance is to several of our native Gnaphalieae. Hope any control measures can avoid collateral damage from misidentification...

Posted by jdmore almost 2 years ago (Flag)

Hi Jim, two records below of our little guy.... Looking at types on JSTOR, it definitely looks like Lasiopogon muscoides. we should write this up in Canotia or somewhere, right? It's a good story for iNaturalist p.r. not to mention it would be fun to speculate how it got here.

my e-mail: elizabeth.makings@asu.edu
https://swbiodiversity.org/seinet/collections/individual/index.php?occid=26781380
https://swbiodiversity.org/seinet/collections/individual/index.php?occid=10372427

Posted by emaking almost 2 years ago (Flag)

@emaking excellent Liz, and glad you were able to confirm the species ID! Do you feel comfortable adding that ID to the iNaturalist records? (See link to the group in my post above.)

I'll definitely be in touch about writing it up!

Posted by jdmore almost 2 years ago (Flag)

I feel confident, especially since it matches the description above. Of course, a correctly identified specimen would be nice.

Posted by emaking almost 2 years ago (Flag)

Hi Jim - thanks for all your detective work on this. At Saguaro NP, we have this collection from last year: https://swbiodiversity.org/seinet/collections/individual/index.php?occid=24346259. I also have photos taken by the collector and it definitely looks like all the Lasiopogon observations on here. Will be interesting to revisit this collection and make a new determination once the herbarium here opens up again.

Posted by danbeckman almost 2 years ago (Flag)

Update: a good definitive identification reference for southern African Gnaphalieae including Lasiopogon and some Gnaphalium can be downloaded at https://www.biodiversitylibrary.org/itempdf/209547

This is Flora of Southern Africa, Volume 33 Asteraceae Part 7 Inuleae Fascicle 2 Gnaphallinae (First Part) by O.M. Hilliard (1983), with thanks to @ngb for the reference!

Posted by jdmore over 1 year ago (Flag)

Update: a manuscript is in final stages of preparation for publication. The species is not L. muscoides - stay tuned! And after a false start, the species now appears to officially be in southern California too: https://www.inaturalist.org/observations/107900354.

Posted by jdmore 5 months ago (Flag)

Update: the paper is now published as Carnahan, Makings, & Morefield 2022. All of the Lasiopogon detected in North America so far appears to be L. glomerulatus.

Thank you to all of the iNaturalist community who contributed to this discovery, many of whom are acknowledged in the paper!

Posted by jdmore 4 months ago (Flag)

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