Infraspecific taxa in botany

Hi
I’m an amateur naturalist and I’m confused, so sorry if my questions aren’t very clear.

I’m trying to learn about botany and I have two questions about infraspecific taxa.

First: A genus has species and then some species have subspecies.
If there are subspecies does that mean that all species belong to one of the subspecies or can some be identified on species level and others on subspecies level?

Is a species level identification still correct if there are subspecies?

Second: Plants of the World is the go to source for plant names, but I don’t really know what to do with some of the search results I get.

They vary:
“This is a synonym of …” is clear.
“This subspecies is accepted” is clear.
“No results” is not clear. Does this mean the subspecies is not recognized or does it simply mean that it hasn’t been added to the database yet?

Thanks for any clarifications!

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Absolutely, many subspecies, not just in plants require extremely specific and detailed keys to separate them.In some cases, subspecies have relatively well defined geographic ranges, but identifying observations to the subspecies level solely on geography is a thorny question. Just because something has accepted subspecies does not mean you should feel obligated to ID at that level if you are not comfortable doing so, a species level ID is still 100% valid and correct.

It could be either, there is no real means to tell.

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You can think about your first question in the same way as you might be able to identify a plant to genus, but are unable to identify its species within that genus. Providing your genus-level ID is entirely appropriate. Similarly, if you can identify to species but not subspecies, providing your species-level identification is perfectly fine.

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It’s important to also remember that POWO is still a work in progress, and is also constantly being updated. While we use it here on iNaturalist for a standard taxonomy scheme, it is not the final authority. There is not a single naming authority in botany. Different taxonomists may have different (and valid) opinions and hypotheses regarding species identities and circumscription.

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Hi @liesvanrompaey, I notice nobody has answered this one yet. I’m confused by what you mean by “…all species belong to one of the subspecies…” and I’m going to assume that you meant that all observations of a species that has subspecies belong to one of its subspecies.

The answer is not easy or intuitive. I’ll start by saying that, as someone has already said, identifying a species with infra-species only to species level is not incorrect.

A species, for example the Tasmanian daisy Bedfordia linearis might have a new subspecies described: Bedfordia linearis subsp. oblongifolia. From a nomenclature point of view, everything that is not Bedfordia linearis subsp. oblongifolia is by definition Bedfordia linearis subsp. linearis, as the latter (known as the autonym) is the automatically generated name for everything else in Bedfordia linearis that does not form part of B. linearis subsp. oblongifolia.

However, there might be as-yet undescribed subspecies, so you’d probably be safer identifying the observation as simply Bedfordia linearis if you are not confident that it is definitely B. linearis subsp. linearis.

I hope this makes sense!

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First: A genus has species and then some species have subspecies.
If there are subspecies does that mean that all species belong to one of the subspecies or can some be identified on species level and others on subspecies level?

Identifying to species when there are subspecies available is not a matter or right vs. wrong, it’s a matter of high-resolution vs. lower-resolution. Plug in the words “genus” and “species” instead of “species” and “subspecies” and, the logic being the same, it will be clear. All members of a genus must be mutually exclusive species. It’s not wrong to call a columbine Aquilegia vs. Aquilegia chrysantha, it’s just less specific. In turn, all members of a species must be mutually exclusive subspecies (when subspecies exist).

The big caveat I’d offer is that this is all subject to the inherent limitations of taxonomy itself. My stridency presumes an infallible species concept (ha) and consistently drawn lines (ha) and a lack of disagreement (ha)

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Thanks everyone!

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That clarifies a lot, thanks!

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I would echo all the great answers above, and just add that I believe those answers would be no different outside of botany – though happy to be corrected by the non-botanists here.

One thing that is peculiar about infraspecific taxa in plants is the two infraspecific ranks, subspecies and variety. Conceptually they are considered interchangeable by most botanists, but nomenclaturally they are different ranks for purposes of authorship, priority, etc. The botanical rules also allow one to create a classification with varieties subordinate to subspecies within a species. But the resulting “quadrinomials” are not formal combinations, and such infraspecific classifications are very rarely used any more.

Maybe more than you wanted to know…? :smirk:

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