About those dandelions

Can you link to a better plant species delimitation study? I’m in a different field and just an amateur botanist, which leads me to some of the same frustration that @jasonhernandez74 was voicing. So when someone referred me to this paper when helping me with some nettles I found it far more convincing than the usual strictly morphological studies based on collections in herbaria (See for example most papers on Arctostaphylos taxonomy that I struggle with because the keys just don’t work in my part of California). I agree that concatenation is 30+ years old and that there are better approaches that might have to be used if necessary. I’m sure you know that the number of modestly well-assembled plant genomes is quite small, so it becomes a matter of time and money, compared to looking at a set of pcr products.

The elevation is 1781 m (5843 ft).

We can now get elevations for observations by clicking the Macrostat link that is found at the bottom of the popup that shows after you click “Details” on the map.

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What is a species? Are species real? The variation we want to name is real. Species, however, are labels that reflect both that variation and our human need for neat, mutually exclusive words. Without species names, we can’t talk effectively about the variation out there.

For the scientific side of the issue, the book Speciation by Orr and Coyne is good. For the more human side, the book Naming Nature by Yoon is good. The former is aimed at college biology people, the latter at a more general audience.

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I’ve thought a lot about this, because the “variation we want to name is real” and has consequences. Take the Mytilus edulis complex, where what we presently call cryptic species probably should be subspecies. M. galloprovincialis and M. trossulus interbreed and are not distinguishable except by DNA. Yet the F1 generations are not common even in “hybrid zones” though gene introgression in both directions is very common. The Mediterranean M. galloprovinicialis has completely replaced M. trossulus in Southern California over the past century without anyone noticing until the 1990’s when the invasion was demonstrated by molecular analysis. The mussels are different physiologically: the native M. trossulus is much more tolerant of fresh water than M. galloprovincialis which can suffer massive die-offs when California bays and estuaries are flooded with rainwater during El Niño years. Since these mussels are such an important component of local foodwebs this can have major consequences and management implications.
In another example of consequences, one that I personally love, gall-forming insects are quite able to discriminate between cytotypes of Creosote, something we humans struggle to do in the field, see https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6749999/ “Polyploidy in creosote bush (Larrea tridentata) shapes the biogeography of specialist herbivores”

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In contexts like this I pine for the “practical species concept” of Cronquist:

“Species are the smallest groups that are consistently and persistently distinct, and distinguishable by ordinary means.”

Of course “ordinary means” change over time, and distinctions can exist independently of our ability to perceive them right away. But that said, I think this has de-facto been the concept most broadly used by taxonomists and non-taxonomists alike, and served as a decent proxy for the Biological Species Concept (at least) for a long time.

No doubt cryptic microspecies exist and await discovery within many of the units we still refer to practically as single species, especially the asexually-reproducing ones. But until those microspecies are widely perceptible beyond the few specialists who study them, do they really need to be given our foundational biological communication tool, a name at species rank?

That’s where the dandelion discussion sends my brain at least, without pre-judging what the best answer would be in this case.

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“what is a species” is a big topic in our cave bio course…especially as a lot are highly difficult to visibly determine as so many species look the same. But, even better - some highly variable depending on which type of cave or karst (or even surface spring!) environment and yet it’s all one species clearly by dna, where morphology would make you think otherwise!

Species concepts are just that. Concepts. Nature defies neat little boxes.

At some to be honest…I stop caring and want to just let it be nature, happily undefined.

But because I do try to be correct…I never saw an answer to this, or is the reason because no one knows?

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Yes I’m sure most of them are section Taraxacum, but also yes no one knows haha. North American dandelion diversity is very underexplored because of everyone lumping them into broad categories.

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In Alabama you probably also have members of a southern section (not section Taraxacum, not section Erythrospermae) that only one person knew much about and now he’s dead. Not that I want to discourage you or anything. ;-)

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Looking at your original Posting, and using the iNat. “Compare” option, ONLY the Common appears…

Which one? The Taxon page for Taraxacum has more than 40 sections, and around the same number of species not assigned to sections.

I am on the verge of uploading a bunch of North Carolina dandelions. One stands out, though, as very different from all the rest, in both morphology and habitat, and I wasn’t confident about its section, as it didn’t really seem to fit any of the sections in Bjork’s key. I don’t want to upload it as just Genus Taraxacum, because it will be stuck there forever; but my only other option is to try to assign it to a section.

I forget that southern section’s name. Something like “Mexi . . . .”

I’ll message you Curtis Bjork’s address. You can send him the photos or post them and send him a link to your observation, and he’ll likely tell you what he thinks. Nobody in North America knows more about Dandelion taxonomy than he does. Or wants to, honestly.

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trying to track these at the species level, especially on a community website, is absurd. They may be reproductively distinct, but are not possible to consistently identify, and if you set that as a bar, what happens when you find 50 genetically distinct strains of Mallard, white oak, ponderosa pine, etc etc. Me and my kids are a genetically distinct strain, are we a separate species of human? This stuff completely destroys the concept of species as a meaningful tool. Remember, the idea ‘species’ exists for humans to use, and is a way of placing a messy ecological world into bins humans can understand the world with. But these aren’t bins 99.9% of humans can use or understand in any way, so they are useless.

Don’t get me wrong, the evolutionary biology is fascinating and absolutely these are worthy of research and understanding. But it’s an inexplicable travesty that the Linnaean classification system is being torn to shreds over semantics when keeping them at a below species level solves all those problems and still allows for them to be tracked, for the ultra wealthy who have genetic sequencers, cuz otherwise you aint gonna.

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yeah, but it’s been totally discarded on iNat and several other places over the last few years. People don’t realize it actually makes field ecology and things like wetland ecological inventory literally impossible (so anyone in the field just ignores it). Like, is semantics and getting your name on a paper more important than the field of ecology and the existence of naturalists at all? apparently to a few people it is. But what is really weird is those people are allowed to control iNat taxonomy as well…

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true. but dandelions don’t use iNaturalist, and humans do. and humans have need for categories if they want to create a crowdsourced biodiversity database.

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In Stace’s New Flora of the British Isles, 2nd Edition, the author writes briefly about the fact that 229 microspecies, most of them asexual, have been found in the British Isles, then reaches a more or less practical conclution: “In this work, the microssp. are not treated in full but are aggregated into 9 rather ill-defined section, determination of which is often not easy even after much experience.”

This seems the best approach to me, given that we humans need neat categories that dandelions do not supply.

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Microspecies have also been chosen as the basic unit in some other genera where apomixis occurs, such as Crataegus, Rubus, Erigeron, and Hieracium; it’s not just Taraxacum. Based on a quick check of the number of species in each genus on iNaturalist, I’m pretty sure iNaturalist follows with those as well. Probably because, just like with Taraxacum, there isn’t really any other good option available from external taxonomy sources.

Yes, microspecies identification is inaccessible to most people due to difficulty, time, etc. (especially in North America where we have no idea what microspecies occur; there are a more resources in Europe). I don’t think iNat curators are specifically biased towards microspecies for biological or social reasons; but we’re limited by the options and policies we have to work with.

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Yeah 9 sections are known from the British Isles. 7 introduced sections were identified from BC in Bjork’s paper, I’m not sure how many sections are represented by the native species there.
Flora of North America recognises species in 6 sections, but only a couple species in each section. More sections have been found in North America since that was published; I’m not sure how you would decide what to call a species within those sections in a way that’s consistent with that treatment.

Mexicana, description here and briefly covered more recently here.

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No, because you are not apomictic. When you reproduce, your genetic material combines with that of another strain.

Thank you, I received that message. I went ahead and uploaded those observations, although it should be said that of the four putative species in Section Taraxacum, I’m only confident of two of them. I’m pretty sure that I have one from Section Erythrosperma and several (possibly all the same species) from Section Hamata. Here is the one that I couldn’t get to section.

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If you cultivate a dandelion you will notice that later leaves are different from spring leaves. This made me doubt about the reliability of the spring leaves as a diagnostic character and made me think that, instead, later leaves could be more informative.

I do not know much about section Taraxacum since a comprehensive treatment is lacking. Regarding section Palustria, the diagnostic characters are numerous and regard the shape and the number of outer phyllaries, the presence of pollen, the colour of the stigma, the shape of the achenes and, in the end, the shape of leaves. This leads to a very high numer of combinations. Inside a specific combination there could be many species that are distinguished by small and/or quantitative characters. There are also cases in which the attribution to a specific section is hard.

Anyway, I feel somehow dubious when I read papers in which a species is described without a comparison with all the other morphologically similar species.
In the end, I think that a thorough revision of section Taraxacum would likely lead to a net decrease in accepted species.

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