Seedling98

Fern classification

The Plants Wikiproject has agreed to use the PPG I system for article titles and taxoboxes, while, of course, discussing alternatives in the text. Please do not make changes to articles that destroy the coherence of the set of articles about lycophytes. You are very welcome to start a discussion at WT:PLANTS if you think the project's decision was wrong. Peter coxhead (talk) 10:49, 29 March 2021 (UTC)

I modified the page according to PPG I. In PPG I there are only two groups: Lycopodiopsida and Polypodiopsida. In every major plant biology textbook, Lycopodiopsida corresponds to Lycopodiophyta (zosterophyllophytes are excluded) and Polypodiopsida corresponds to Polypodiophyta/Monilophyta. Since every other division of vascular plants has a Wikipedia page that treats it as a division (Cycadophyta, Ginkgophyta, Pinophyta, Gnetophyta and Magnoliophyta), seeing two pages about lycophytes that give different definitions of "Lycopodiophyta" is confusing for readers. Furthermore, in the page about kingdom Plantae/Viridiplantae, lycopods are called "Lycopodiophyta" while ferns are called "Pteridophyta", instead of "Polypodiophyta" (but clicking "Pteridophyta" directs you to "Polypodiophyta"). I suggest at least to change "Pteridophyta" into "Polypodiophyta" on the Plantae page, since "Pteridophyta" is no longer a valid taxon and includes both ferns and allies and lycopods.

Sorry, my comment above applies to only some of your edits, which wasn't clear. You clearly understand the issues, which all too often editors who make this kind of change don't.

PPG I does not deal with extinct plants, and doesn't have a name for the combination of Lycopodiopsida and Polypodiopsida. So we have a problem in reconciling the palaeobotanical literature with PPG I. There are two issues:

1. the relationship between zosterophylls, Lycopodiopsida (sensu PPG) and ferns
2. what these groups should be called

(1) varies considerably in the literature. The page we have now is much influenced by Kendall & Crane (1997) (see Lycophyte#Phylogeny) which in spite of its age remains the most complete account of the phylogeny of early land plants. Hao & Xue (2013) take a different view. We could treat "lycophyte" as an informal name for Lycopsida/Lycopodiopsida, and abandon the Kendall & Crane view, which could be justified, but what would you then do with the material at Lycophyte?

(2) is a real problem. Although standard textbooks use divisions/phyla, no recent cladistic/molecular phylogenetic account that I know of uses these ranks in the way the textbooks do. If division is used, it's placed much higher, e.g. Tracheophyta or Embryophyta (under various names). The divisions in the table at Plant#Diversity would be impossible to source in the recent literature as far as I know. I do agree with your last point, and have changed the table.

Peter coxhead (talk) 16:23, 29 March 2021 (UTC)

Thank you for editing the Plantae page! I see your point on lycophytes. I have never seen the classification of Kendall and Crane, so I am accustomed to read "lycophytes/lycopodiophytes" (phylum Lycophyta/Lycopodiophyta) and "zosterophyllophytes" (phylum Zosterophyllophyta). I thought lycophytes sensu lato was a 'niche' definition.

It is a 'niche' definition in one way, because it's almost entirely restricted to the palaeobotanical literature. The problem is how to handle the sometimes conflicting approaches, plus the virtual abandonment of higher ranks in the recent phylogenetic literature. Neither APG nor PPG help in this respect. You'll perhaps notice that we tend to use informal ranks like "clade" for higher levels in taxoboxes, as for example at Flowering plant. Peter coxhead (talk) 19:46, 29 March 2021 (UTC)

Seedling98, you are invited to the Teahouse!

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