Talk:Eudicots/Archive 1

Archive 1

Taxonomy query

Note that these names are not formed in the manner specified by the International Code for Botanical Nomenclature so are only provisional, and not the valid names for the groups. The valid name for the "eudicots" and the other groups given here have yet to be selected or determined.

This is inaccurate. The names eudicotyledon and tricolpates are valid names for the group, in the same way that monocotyledons is a valid name for its group. They are not valid names for the formal ranked taxon corresponding to the group, should one be used, but that's a different matter. And as stated repeatedly, systems that treat the eudicots as a class call must call it the Rosopsida, so the claim that the name hasn't been selected is false.

Repeatedly where? And if so, why are those silly 'Euro-sid' names still there? Group names prefixed Eu- are definitely proscribed by the ICBN - MPF 21:37, 12 Mar 2004 (UTC)

Twice here, and once on flowering plant. The "silly" names are here because those are the names of the groups in question, as used by the majority of people discussing relationships. They don't have to conform to the ICBN because they're not formal ranked taxa, which haven't emerged yet and ultimately may not correspond to them. In general, the informal names are better for discussion when the classification is unstable. Rosopsida can refer to the eudicots, to some subgroup of the eudicots, or to nothing depending on the author. Eudicots always refers to the same thing, which happens to be called Rosopsida when treated as a class. Are we really going to have to explain the difference between clades and taxa on every single page where the latter are unsettled? -- Josh

Thanks for the clarification, but it wasn't at all obvious, with the way the ICBN names were not emphasized. All this being the case, there is definitely a need for an explanation on the page about why the ICBN is not being followed. MPF 23:16, 12 Mar 2004 (UTC)

It isn't being followed because it only applies to formal taxa. That's something that should be explained on the ICBN page, not here.

PhyloCode names are formal taxa under PhyloCode rules, but they are not formal ranked taxa. In other words, they don't have to conform to certain rules such as standard endings, but there is a whole set of PhyloCode rules. As Josh said, PhyloCode names are VERY specific, and immutable. I just wanted to add that the director of the PhyloCode website mentioned that "Tricolpates" is the preferred name; I plan to quiz him on some more. jaknouse 00:09, 13 Mar 2004 (UTC)

Cladonomy

This is a "nice" example of Cladonomy. Berton 13:57, 24 August 2006 (UTC)

Importance/Quality

Whether this article is the important one, or Dicotyledon, or both, kind of depends on how we organize the material. But eudicots are one of the largest and most familiar groups of plants, and we could have more material (and better-organized material) about things like common traits of eudicots, their molecular biology, adaptations, etc, etc. Kingdon 23:53, 20 March 2007 (UTC)

Taxoboxes for clades?

I'm removing the taxobox because "Eudicots" is not a class nor a taxon at any level. I'm not sure if "taxoboxes" have been added to any of the other unranked clades of the APG II system but feel free to discuss it at either Wikipedia talk:WikiProject Tree of Life or Wikipedia talk:WikiProject Plants. MrDarwin 16:44, 27 April 2007 (UTC)

The are lots and lots of clades in the taxoboxes. They are part of the tree. In this case they can be situated as plants and eukaryotes. Then, there is the need of a taxobox. "Clades" are considered "unranked taxons". They are not out of the tree! 80.30.238.120 11:06, 7 August 2007 (UTC)

There are plenty of taxoboxes for unranked clades. I'm especially thinking of the higher groupings of animals and protista, although browsing around also saw at least one case where someone removed a taxobox (without explanation, so it is hard to know what the reasoning was). Insects might be another case where recent systematic work uses clades rather than ranked taxa (I'm far from an expert on that one, though). I guess I don't see the argument against taxoboxes, especially if there seems to be some modicum of agreement about what the clades are. Kingdon 18:40, 12 August 2007 (UTC)

I think it's a bit weird personally, and would generally like to see taxoboxes used only for ranked clades--you know, other stuff exists not being an argument. KP Botany 19:43, 12 August 2007 (UTC)

Correct me if I'm wrong, but the whole point of the taxoboxes in the first place was to keep track of taxa. The problem with the taxobox as it now appears in this article is that it is confusing taxa with clades. Yes, clades can be taxa, but that means they have to be given (1) a taxonomic rank and (2) a name. And now the perfectly good orders are being called clades--which they only are in the context of their definition and circumscription by the Angiosperm Phylogeny Group. MrDarwin 21:08, 12 August 2007 (UTC)

My bad, I meant taxa! I don't want it used for mixed clades and taxa, simply the name at the appropriate taxonomic rank according to an authority. I think it's weird to use them for mixed systems, constitutes original research, and confuses the heck out of users, particularly without authorities for the nomenclature in the taxobox, there is no way we should be mixing clades that are not firmly in the hierarchy. KP Botany 21:21, 12 August 2007 (UTC)

KP, I didn't mean it as a criticism of you or your comments and didn't realize it read that way--my comments were directly solely at the taxobox in the article and the way it was presenting its information--which had been added & edited by another editor entirely. MrDarwin 23:28, 12 August 2007 (UTC)

Thanks, Mr. Darwin, I wasn't worried about being criticized so much as being clear, particularly after saying so many times that I want taxonomies in taxoboxes to be attached to specific references, I don't want to be seen as saying they should be more mixed than they already are--something I consider very problematic about taxoboxes in general. Adding APGII clades to the various plant taxonomies already contained in the taxoboxes is, imo, a step in the wrong direction. I was more horrified by what I said, than worried about being criticized. KP Botany 03:30, 13 August 2007 (UTC)

The title

should be singular. — Preceding unsigned comment added by 70.230.159.92 (talk) 03:17, 1 September 2012 (UTC)

Section 'Subdivisions' should be more than a list.

I hate to complain about a problem, rather than just fix the problem, but I really don't know enough about biology to be productive here.

The Problem: I read eudicots, rosids, and asterids. Although each article lists some representative species, I (the reader) have no understanding what criteria was used to subdivide eudicots into rosids and asterids (and others). Why is one plant a rosid but not an asterid? These articles read as though plant life is subdivided arbitrarily, though I suspect the subdivision is somewhat rational. My intuition tells me that there must be some expressible, meaningful distinction between these subgroups.

The Proposal: Is there some way to describe the grouping here? I propose a brief summary of the characteristics which divide rosids and asterids. I think this summary should be a list of differences, each difference taking this form:

• Rosids feature X. In contrast, Asterids feature Y.

Thanks, 71.63.4.110 (talk) 22:42, 15 November 2014 (UTC)

Modern classification is based almost entirely on molecular phylogenetic studies, so the eudicots are divided up the way they are because their gene sequences suggest that's the way they evolved. Once the groups are set up in this way, it's then possible to look for more obvious differences, but these are secondary and there may be few common features. Mauseth (Botany, 5th ed. p.565) says of rosids, for example, that they are "so diverse with respect to vegetative body, flowers, chemistry, and ecology that it is difficult to see that they are all related". Asterids are a bit easier to characterize. I agree that we should try to add something to the article. Peter coxhead (talk) 08:32, 16 November 2014 (UTC)

Thank you for your reply. I now understand why it is difficult to write more than a list of subdivisions. In essence, the words 'Eudicot', 'Asterid', and 'Rosid' refer to ancient common ancestors (ignoring horizontal gene transfer), not to collections of common traits. Still, if we can't describe the distinction, then the names don't convey much information and I question the merit of these articles. A few ideas spring to mind:

• Since these groups are divided according to their genotype (rather than phenotype, as I had incorrectly assumed), would it be easier to describe the characteristics of the genome which divide rosids and asterids? Something like 'The fourth chromosome of rosids have X; In contrast, the fourth chromosome of asterids have Y'?
• Have biologists tried to characterize these common ancestors in a manner analogous to how linguists attempt to reconstruct proto-languages? If so, perhaps the articles could describe the reconstructed common ancestors.
• Other than assigning new species to the taxonomy, how do biologists use the distinction? If the only use is to assign new species to the taxonomy, then the taxonomy is merely write-only documentation.

Thanks, 71.63.4.110 (talk) 16:35, 16 November 2014 (UTC)

Well, I'm not a professional botanist, but my impression is that the very top-level clades aren't particularly useful, other than as a grouping of orders and families. Thus a new species would be assigned to a genus, or a new genus to a family, and hence it would belong in one of the higher-level clades. If you go to the main tree in APweb and click on the names there is some information on each of the clades (APweb is regarded as a very reliable source although only a website.) As I noted before, we need to try to get some of this information into the articles. Peter coxhead (talk) 17:32, 16 November 2014 (UTC)

Peter's right -- these higher clades are ridiculous hard to define in terms of characters that make them unique, but this problem is not restricted to top-level clades. The family Orchidaceae is really best circumscribed by a single character: presence of a protocorm stage of development. The other characters often cited for Orchidaceae are not unique to it or have some reversals/exceptions. For asterids, the characters considered defining are the presence of iridoids and ovules with a single integument. There aren't decent synapomorphies for the rosids yet, if I recall correctly; I'll check my references to confirm that. Rkitko ^(talk) 23:47, 16 November 2014 (UTC)

Thanks, both. I browsed the APweb site for a while, but I'm clearly out of my league in this area. I don't think I'll be able to add the new content to these articles, though I'd be happy to copyedit or otherwise clean up. 71.63.4.110 (talk) 14:29, 18 November 2014 (UTC)