iNaturalist Vascular Plant Working Group's Journal

October 26, 2019

Proposal to consolidate bracken taxonomy

In light of a recent publication in American Journal of Botany by Wolf et al., (, I'd like to rearrange our bracken (Pteridium) taxonomy in line with the molecular phylogenetic approach taken by Thomson and others. Of particular value in understanding the situation is Thomson's 2008 article in the Fern Gazette: which describes the "aquilinum" and "latiusculum" morphotypes; most continents have at least one taxon corresponding to each morphotype, but genetic studies, such as Wolf et al., have shown that brackens on the same continent are more closely related to each other than to other taxa of the same morphotype.
Under the approach of Thomson, we would divide Pteridium into four species: Pteridium aquilinum, diploid, of the northern hemisphere and Africa, Pteridium esculentum, diploid, of the southern hemisphere, and the hybrid allotetraploids Pteridium caudatum, of Florida and Central and South America, and Pteridium semihastatum, of southeast Asia and northern Australia. Within P. aquilinum, 11 subspecies would be recognized, most of which already exist in our taxonomy as subspecies or varieties: ssp. aquilinum (Europe), ssp. capense (Africa), ssp. centrali-africanum (Africa), ssp. decompositum (Hawaii), ssp. feei (North America), ssp. japonicum (Asia), ssp. latiusculum (North America), ssp. pinetorum (Europe), ssp. pseudocaudatum (North America), ssp. pubescens (North America), and ssp. wightianum (Asia). Within P. esculentum, 2 subspecies would be recognized: ssp. esculentum and ssp. arachnoideum. (P. esculentum ssp. arachnoideum, in this sense, was recently further divided into subspecies by Schwartsburd et al. on morphological grounds, but these are not yet in our taxonomy and I would prefer to wait for molecular evaluation before recognizing them.)
Aside from the promotion of some varieties to subsspecific rank, this would require swapping our current P. arachnoideum to P. esculentum ssp. arachnoideum, P. latiusculum to P. aquilinum ssp. latiusculum, P. pinetorum to P. aquilinum ssp. pinetorum, and P. revolutum to P. aquilinum ssp. wightianum. P. tauricum would be submerged in P. aquilinum ssp. aquilinum. P. aquilinum ssp. lanuginosum, of somewhat unclear application, would be merged into P. aquilinum, while P. aquilinum var. champlainense, of doubtful distinctness, would be merged into P. aquilinum var. latiusculum, as in Cody (Ferns and Fern Allies of Canada).
This taxonomic arrangement seems fairly reasonable to me: the genetic data in Wolf et al. suggest that species should be delimited rather broadly, while the plethora of recognized subspecies allows for continued recognition of morphological variation on different continents, e.g., the distinctness of ssp. pinetorum from ssp. aquilinum. However, I'd like input from other curators: @apseregin, your thoughts would be particularly welcome, as the Russian iNat community has been making heavy use of P. pinetorum lately.

Posted on October 26, 2019 05:23 by choess choess | 4 comments | Leave a comment

June 02, 2019

Generic division in the lycophytes

Vascular plant curators here are probably already aware that there's a significant variance between the classification for ferns adopted by POWO, and PPG I; the latter (in my opinion, anyway) has more support among the pteridological community and we've adopted it as our classification scheme. (Hopefully this summer I'll have time to get back to adding deviations to harmonize the two.)

However, a similar problem exists with regards to lycophytes, specifically family Lycopodiaceae. Older systems treat this family as monogeneric, containing only genus Lycopodium. More recently, the deeper divisions in the family have been recognized and Lycopodium sensu latissimo has been split up; the question is, how much to do so.

PPG I recognizes 16 genera in Lycopodiaceae, divided among three subfamilies: the Huperzioideae, Lycopodielloideae, and Lycopodioideae. By contrast, POWO treats each of those subfamilies as the broadly circumscribed genera Huperzia, Lycopodiella, and Lycopodium, respectively.

Our existing taxonomy, owing in part to its roots in Flora Novae-Angliae, generally inclines towards the "splittier" approach taken by PPG I. My personal sense of taxonomic trends is that the degree of splitting in PPG I, which was pretty forward when Haines wrote it into Flora Novae-Angliae, has now become pretty widely accepted and that we should adopt PPG I for lycophytes as well as ferns.

The main impact would probably be in the tropics, where Pseudolycopodiella and Palhinhaea would get split from Lycopodiella, a bunch of Huperzia would get moved over to Phlegmariurus (which is active in our taxonomy, but many species have not been moved). The Palhinhaea split would probably be the most visible, as Palhinhaea/Lycopodiella cernua is an extremely common pan-tropical clubmoss.

I'd like to know if other curators are on board with this approach; @crothfels who has brought up some of the inconsistencies in our current taxonomy.

Posted on June 02, 2019 03:45 by choess choess | 14 comments | Leave a comment

September 30, 2018

Splitting Pleopeltis polypodioides (resurrection ferns)

iNaturalist current policy/guidelines currently inform us that genera that start with the letter P and ferns are not quite complete on Plants of the World Online, iNat's taxonomic authority for vascular plants. Here's one that fits both those categories.

Split Pleopeltis polypodiodes (sensu lato) into --->

  1. P. polypodioides (sensu stricto)
  2. P. michauxiana
  3. P. ecklonii
    (see drafted taxon change)

This also includes first merging P. polypodioides subsp. ecklonii into P. ecklonii. (see drafted taxon change) The split is in accordance with the following references and per the discussion recently taking place on this flag: Pleopeltis polypodioides (sensu lato) is a widespread species, occurring in North, Central, and South America, the Caribbean, and southern Africa. P. polypodioides (sensu stricto) in in the proposal here is a taxon with distribution in Mexico, Central America, South America, and the Caribbean, but excluding most of the United States--excepting extreme southern Florida--and southern Africa. See Sprunt 2010 above for more information about this split, which was proposed on the basis of limited overlapping ranges, phylogenetic, and morphological analyses; of the latter,
Even though no single morphological character can be used to distinguish among all taxa, a combination of characters can be used to identify each taxon. The most important characters include the presence or absence of scales on the adaxial surface, the location of the gland (or hydathode) on the laminar surface (Fig. 3.3), the presence and length of the sclerotic band in the rhizome scale (Fig. 3.5), leaf venation (Fig.3.4), and rhizome scale margin.
The resurrection fern covering the southern United States, eastern Mexico, and parts of the Caribbean has been elevated to species status as P. michauxiana and the southern African species is P. ecklonii. See the atlases below for rough ranges. Mainly, there are several hundred observations of resurrection ferns in the southern United States on iNaturalist that will be reassigned to P. michauxiana once this split is committed. Note that in Sprunt's 2010 dissertation there are several additional taxa raised to species level. At this time, this split only includes the elevation of P. michauxiana and P. ecklonii based on the published names and recognition in regional authorities as well as Plants of the World Online. Review the output taxa atlases prepared by myself, @coreyjlange, and @choess. Identifications of P. polypodioides (sensu lato) will be automatically reassigned to one of the three output taxa based on these atlases. Where atlases overlap, identifications of P. polypodioides (sensu lato) will be reassigned to genus.
  1. Atlas for P. polypodioides (sensu stricto)
  2. Atlas for P. michauxiana
  3. Atlas for P. ecklonii

The purpose of this journal post is to gain rough consensus on going through with the split despite the current policy. If there is anyone that disagrees with it, please do include the basis of the disagreement. See also previous discussions in which everyone seemed on board with accepting P. michauxiana, which was accepted by the then-iNaturalist regional authority Weakley 2015: a flag and taxon change from ~7 months ago.

Pleopeltis michauxiana in Mississippi, US

Tagging in some of the most active curators, members of this project, and top Pleopeltis and Polypodium observers and identifiers. My apologies if I missed tagging you here. If you're not tagged, please do include yourself in the discussion. :) @aaronliston @ajwright @alexiz @americorp_jeffrey @aztekium_tutor @berkshirenaturalist @bobby23 @bodofzt @borisb @boschniakia @brownsbay @charlie @choess @cmcheatle @coreyjlange @cosmiccat @crothfels @dgreenberger @duarte @efmer @erikamitchell @erwin_pteridophilos @graysquirrel @grnleaf @gwark @hfabian @hkmoths @jakob @jasonrgrant @jdmore @jonathan142 @jrebman @juancarloslopezdominguez @jwalewski @kai_schablewski @kevinhintsa @kokhuitan @kueda @leonperrie @loarie @mangum @marykeim @mateohernandezschmidt @maxkirsch @mikepatterson @milliebasden @monifern @mrfish33 @nathantaylor7583 @norm_shea @philjrenner @reallifeecology @rfoster @robertarcher397 @ryan84 @ryancooke @sea-kangaroo @sedge @stevejones @tiggrx @tonyrebelo @treichard @tsn @valerietheblonde @wdvanhem @whiteoak @wisel

To view the project where this journal entry was posted, and join it if you wish, head to the iNaturalist Vascular Plant Working Group homepage and hit "Join" in the upper right corner.

Posted on September 30, 2018 16:07 by bouteloua bouteloua | 17 comments | Leave a comment

September 10, 2018

Diplacus dilemma in California area

The common ex-species Mimulus aurantiacus that occurs in California and Baja California was split into several species of Diplacus under the new taxonomy. However, all of the many M. aurantiacus observations are now classified as D. aurantiacus when in reality most of them are one of the other species. See this post: as well as this paper: and other references linked in the post above. While some may know i am an unapologetic lumper when it comes to plant taxonomy, i don't have a problem with these species divisions, but am worried about how we deal with them.

I may have missed out on some of the procedure here, in terms of sensu latu vs sensu stricta but I'm concerned about cases where a large 'species' is split, in that i don't think we should just be lumping all on the observations into one species. Tossing them back to genus is very problematic as well, though. I am wondering... is there a way to move the previous M. aurantiacus into a separate place until the community can review them, either 'D. aurantiacus sensu latu' or else a grab bag subgenus? Otherwise... we've created a huge slug of wrong IDs, and because of how community ID works it's a huge slog requiring multiple people to get these swapped over to the correct ID, especially in cases of multiple IDs by no longer active users.

Thoughts? @loarie ? I am not sure who else is working on California taxonomy? @bouteloua I know this isn't your geographic area of expertise but you've been pretty involved with this process. Anyone else? @jdmore ? Is the policy to toss the splits into one species like this? Or are there just very few of them so it's a special case? Apologies if this was already addressed, i haven't had as much time to devote to this as I'd like...

Posted on September 10, 2018 01:54 by charlie charlie | 51 comments | Leave a comment

August 20, 2018

Transition to Plants of the World Online as a taxonomic reference

iNaturalist used to use several regional floras as vascular plant taxonomic references with The Plant List as the tie-breaker. As discussed here, we are now using Plants of the World Online (POWO) as the primary vascular plant taxonomic reference with two exceptions:
1) POWO isn't yet complete for genera beginning with the letter 'P' (e.g. Phacelia) or Ferns (Class Polypodiopsida).
2) We maintain a list of potential deviations from POWO that we will discuss on a case by case basis. Those we determine to be 'Accepted Deviations' take precedence over POWO.

If you'd like to propose a deviation from POWO, flag the taxon (if its not already flagged) kick off a discussion for why you think the name is valid despite not being in POWO and also add the name to the list of potential deviations.

Here's a decision tree for how to go about helping resolve vascular plant species in iNaturalist that are not in POWO:

Names added to the potential deviation list will be discussed (in their corresponding flag) and potentially discussed with Kew Botanical Garden staff (which maintains POWO). From there we will decide whether to go with POWO or maintain them as 'Accepted Deviations'. As POWO updates, any corresponding rows should be removed from the potential deviation spreadsheet.

For example, Lithospermum parviflorum is an active species in iNaturalist not valid in POWO. It was added to the potential deviation list while @bouteloua led a discussion that seemed to indicate that it should be valid in POWO. This recommendation was brought to the attention of Kew and they agree it should be a valid species. We responded by marking it as an 'Accepted Deviation'. If Kew updates POWO by adding Lithospermum parviflorum, it should be removed from the list (as it will be no longer needed).

Posted on August 20, 2018 23:34 by loarie loarie | 58 comments | Leave a comment