Talk:Heterospory

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This article was the subject of a Wiki Education Foundation-supported course assignment, between 5 January 2021 and 12 March 2021. Further details are available on the course page. Student editor(s): Hrobertson2. Peer reviewers: ConnorGomez.

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The second sentence in the Origin of Heterospory is not a fact. I would re-word it to say that "some research done concludes the possibility of." The addition of the author or sciencest into the sentence would be good too. Aivaldez94 (talk) 03:08, 13 April 2017 (UTC)[reply]

This article is or was the subject of a Wiki Education Foundation-supported course assignment. Further details are available on the course page. Student editor(s): Vostroyan1, Ahweiss2. Peer reviewers: Aivaldez94, Hsp.miller.

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Hi plantsurfer, Vostroyan1 and I are the students working on this page through our university. Our professor has expressed concern about the following passage. She does not fully aggree with the content and would like to see a source. As this was from the original article before we started we would like to ask if you know more about this Ahweiss2 (talk) 20:37, 19 April 2017 (UTC)[reply]

"In exosporic species, the smaller spores germinate into free-living male gametophytes and the larger spores germinate into free-living female gametophytes. "

Hi Ahweiss2. "Exosporic" means that the gametophyte develops into a multicellular organism outside the spore, so to that extent the statement is correct. Homosporic (isosporic) species were originally, and remain today, exclusively exosporic. However, it needs to be made clear that early heterosporous species also had exosporic, free-living gametophytes. A well-known example is the late Devonian tree species

Archaeopteris halliana. Only heterosporic species evolved endospory such as that exhibited by the seed ferns and arborescent clubmosses. And of course, all modern seed plants are heterosporous and have endosporic gametophytes. Good sources for these points are the references cited by the article, such as Stewart and Rothwell. Hope this helps. Plantsurfer 21:09, 19 April 2017 (UTC)[reply

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Hi @Plantsurfer, I am studying nonseed plant evolution and I am wondering if the sentence in the lead paragraph about heterospory evolving from clubmosses is accurate. In the article on Lycopodiopsida, it mentions that "Club-mosses (Lycopodiales) are homosporous, but the genera Selaginella (spikemosses) and Isoetes (quillworts) are heterosporous". Thank you. RowletChess (talk) 08:46, 14 May 2023 (UTC)[reply]

@RowletChess, No, the article does not say that. Heterospory evolve independently and convergently several times in different plant groups. The herbaceous Lycopodiales of today are homosporous, but their extinct arborescent relatives such as Lepidodendron were heterosporous. Bateman and DiMichele in the title of an influential paper described it as "the most iterative key innovation in the history of the plant kingdom". The link to the paper is here: https://doi.org/10.1111/j.1469-185X.1994.tb01276.x Plantsurfer 10:29, 14 May 2023 (UTC)[reply]

Hi Plantsurfer, I read the article and it mentions on page 367 "showed only a single origin for heterospory within the monophyletic lycopsid (clubmoss) clade, as a synapomorphy of the Selaginellales plus the Rhizomorphales (lepidodendraleans plus isoetaleans...".

It's true that heterospory evolved independently in Lycopodiopsida. But if we were to assume that clubmosses (Lycopodiales) are excluded in monophyletic clade, then would it be more accurate to say heterospory evolved in lycopsids and not clubmosses specifically? Cheers. RowletChess (talk) 13:25, 14 May 2023 (UTC)[reply]

The terminology is confusing, full of alternative names and names that are loosely applied. Lycopodiopsida is the name of a Class of plants; All of this class are frequently referred to as clubmosses (sensu lato), but in the strict sense this refers only to the Order Lycopodiales. The clade name Lycophytes and the name Lycopsida are synonyms of Lycopodiopsida. Heterospory first appeared in Carboniferous period in the clade of clubmosses that has ligules associated with their microphylls. The Order Lycopodiales which includes extant herbaceous clubmosses, such as Lycopodium, did not have ligules, but the clade including Selaginella, Isoetes and the extinct Lepidodendrales do/did. Heterospory first appeared in this ligulate group of Lycopods. If you have access to the book Stewart, Wilson N. & Rothwell, Gar W. (1993). Paleobotany and the Evolution of Plants (2nd ed.). Cambridge University Press. pp. 150–153. ISBN 978-0-521-38294-6 it may help.Plantsurfer 14:11, 14 May 2023 (UTC)[reply]

Thank you RowletChess (talk) 14:20, 14 May 2023 (UTC)[reply]