01 de novembro de 2023

The current state of Heterotheca on iNaturalist (and how it got this way)

I've been working on the genus for my doctorate research for the better part of 20 months or so at Univ. of Oklahoma, trying to resolve discrepancies between Nesom's and Semple's taxonomy through a mixture of observations (in the field, herbarium, and online mostly through iNat), molecular phylogenetics (DNA work using HybSeq and RAD-seq), hopefully some greenhouse experiments (grew ~10 species this year mostly from seed collected last year), and likely some morphometrics (in a similar way that Semple used when making taxonomic decisions). This is an exceptionally complicated group with an enormous amount of variation and intergradation of vegetation and floral features (often revolving around pubescence and glandularity patterns). Several species complexes for the perennial species (H. fulcrata, H. oregona, H. sessiliflora, H. stenophylla, and H. villosa) do not make any sense at first glances; it has taken me this long to vaguely understand each man's treatment of the H. fulcrata and H. stenophylla complex while also coming up with what previously unrecognized concepts/taxa might warrant some formal recognition. I have not even started looking at the California/Pacific Coast complexes, and it's taking me a long while to conceptualize the H. villosa species complex(es) from either man's perspective. I'll be going through the northern Great Plains iNat observations over the next few weeks and hopefully come away with some understanding of which of Nesom's names apply to what.

It's important to note that Phytoneuron is not peer-reviewed, especially not when Nesom is the sole author and editor of the journal (and particularly when peer reviewers, who he selects personally, are not listed in his own work). The journal has its place for some taxonomic purposes, but its lack of modern peer-review standards (especially when he is the sole author) is not really debatable. There aren't rules strictly preventing Nesom from self-publishing whatever he wants in Phytoneuron, but the findings published in such should be viewed with great skepticism. No morphometrics, statistical comparisons, sequence data, or any other form was used in his treatment of Heterotheca. During multiple times, the significance of morphological analyses were discarded (as Guy does not think such need to be necessarily correct, as he will tell you). In his other articles, he has also criticized people for relying upon molecular phylogenetic data (see his article of Toiyabea and other Astereae) and does not appear to fundamentally understand how they work (see his concepts of Doellingeria/Eucephalus). He is a very good 19th century botanist as Semple has acknowledged, with a keen eye for small details - but his publications should never been blindly accepted as if they were subject to the same standards as other journals require (either in terms of data used or peer-review).

That said, this is not to say that Semple's treatment should be taken as bible either. I disagree with both's treatments of the H. fulcrata complex, for instance, and think that Nesom's is probably closer than Semple's is in this regard (but completely disagree with Nesom's treatment of Arizona populations). Semple's conception of the H. stenophylla complex (H. canescens and H. stenophylla var. angustifolia and var. stenophylla) makes a lot more sense to me than Nesom's does, especially after field work this year and last year, but neither appears wholly correct. Semple, like Nesom, lacked any robust molecular phylogenetic to inform his decisions better (though he did include a mixed morphology/chloroplast tree in his '96 monograph). He also lacked access to digitized specimens the way that Nesom had, making it more challenging to know what is where (though he did annotate >10,000 specimens by the mid-2000's).

The reason that I've been going along with the names on iNaturalist (which follow Nesom's treatment) is because Patrick Alexander had switched things over and had identified >3,000 observations on here already. The amount of work, as someone new to the genus during spring '2022, seemed pretty insurmountable. It would be going against the tide to follow Semple's treatment at the time (and even more so now) when people are adopting the new treatment, leading to a greater proportion of taxa left at "Heterotheca" (Patrick had not yet made the subgroups of "Phyllotheca", "Heterotheca villosa complex", and so on per my request) and thus less useful to countless people (myself principally included since I've been going around looking for these taxa/populations). The amount of work to go along with things was great, given that virtually everyone at the time followed Semple's treatment (since all of the floras followed it essentially), but trying to halt it and revert things back would be of similar resistance and difficulty (or at least as much as I predicted). The problem now is that almost no one knows what to call anything anymore since the name changes from the two treatments was colossal in some regions (not so much in states like Illinois, drastically so in places like Colorado). The name changes were overall so complex that it's not just a variety raised to species but now one variety is now like five species all falling under the umbrella of 'Phyllotheca' or their respective 'complex' taxon. Or it's things lumped in a way that's hard to backtrack, and the effort required to learn all of these changes and recognize these new taxa relative to the old concepts is deeply prohibitive. It just isn't worth it for 99% of people to try figuring out what all changed, so most stuff is now just 'Heterotheca' or 'Heterotheca villosa' because it just isn't worth it for anyone not specifically working on the group.

E.g. some people are now calling all 'Heterotheca villosa' they see 'Heterotheca hirsutissima' (including those from Michigan or Canada as I recently saw), but most people just leave things at H. villosa (leaving Patrick or myself to try fixing the ID's sent our way). The other problem is that there is a "real" Heterotheca villosa, but now that only encompasses H. villosa var. villosa (and var. foliosa) from Semple's treatment, so the actual number of "correct" H. villosa's is ridiculously small compared to the amount of "H. villosa" sensu Semple that encompassed most of the western United States (and parts of Canada). Finding those is now virtually impossible unless multiple people (to ensure the ID's reach a majority consensus) go back and identify the thousands of observations uploaded from all over North America. The amount of effort taken to switch everything over is going to take literal months, and there will always be a lag as new observations are made according to the old treatment (leading to mixed iNat observations and herbarium collections). Some specimens with duplicates now go by multiple names (ex. H. excelsior, H. villosa, H. villosa var. scabra), and it just isn't realistic to have someone spend weeks trying to sort out all of the names and correct the tens of thousands of existing Heterotheca herbarium specimens out. So basically, unless Nesom, Patrick, or myself personally visit an herbarium to correct things, there's going to be pretty substantial confusion as to what's going on. This has been particularly frustrating for someone trying to study the group because I have to convert all of the names to one system to understand what occurs where and hope/pray that things are identified in the right species complex at least.

I cannot overstate how frustrating I find the belief that "publishing is to make research available rather than to certify that research is correct" is to modern systematics. Most people (or biologists even) are not systematists and will not have the background/expertise to discern among what should be recognized and what shouldn't be without a great deal of time/effort. Most people are going to see a paper describing a new species and take it as properly verified that should be adopted (Alan Weakley and I had a large argument about this with Nesom's Euthamia paper). Nesom's Heterotheca has certainly started a discussion and made his thoughts available, but its rapid adoption was unwarranted for the above reasons. Articles should be as correct as can possibly be due to the aforementioned problems it has created. People read them with the implicit understanding that they have been rigorously reviewed and tested for authenticity, and, when neither is true, conundrums such as the current one ensue. I will try to resolve the current taxonomic situation, but this will take me years to accomplish.

Slightly modified from https://www.inaturalist.org/observations/53882197

Posted on 01 de novembro de 2023, 12:36 PM by marisaszubryt marisaszubryt | 0 comentários | Deixar um comentário