Garak via pbs
Sat, 13 Mar 2021 11:20:09 PST
Hi Cody,

I'm answering here without the rest of the list, as very few 
Lysimachia-Species fall into the scope of the PBS (then again: L. 
punctata goes completely underground in winter for me, we actually could 
add it....). I know I was being provocative about campanula, and not too 
fair about Lysimachia. I guess I'm more of a splitter than a lumber, I 
like my Genera in tidy little packages - I'm rather unhappy that the 
very good proposals for splitting Iris have'n been recognized, and I'm 
happy with what has happened to Scilla. Of course the paper you linked 
suggests it won't be easy to do such splittings for Lysimachia. Seems to 
be a case of a whole set of bi-stable switch genes, like flower symmetry 
in Moraea. Not a pretty situation (if you are a splitter, that is). I 
wonder if a more diverse set of DNA sequences would help improving the 
branching resolution by making it easier to tell parallel evolution and 
common ancestry apart...

Seems like a story to be continued...


Am 13.03.2021 um 17:35 schrieb Cody H via pbs:
> Martin,
> The real problem with genera like Lysimachia is that (plant) evolution is
> not as simple as we were led to believe. In this case, the former generic
> concept for Lysimachia does not appear to actually map to a coherent
> lineage of plants.
> I’ve attached a screenshot (I hope) from one of the more recent (2008)
> phylogenetic studies on the group that I found with a cursory Google
> scholar search. If anybody knows of a better/more recent one, by all means
> please share it. A link to the study (open access) is here:
> What you can see in the screenshot is that “Lysimachia”—which I am assuming
> represents the species included in the former generic concept—is all over
> the place in the diagram, indicating that these species are (likely) not
> all as closely related to one another as their morphology alone would
> suggest. Another problem is that there is a severe lack of resolution along
> the part of the phylogeny that systematists often refer to as the
> “backbone”—indicated in the diagram by many groups branching from the same
> (long) vertical in the tree, the interpretation of which is “the
> data/analysis are insufficient to clarify the relationships are among these
> various groups”. This is a common problem in groups of organisms that have
> experienced rapid diversification in the distant past, because there is
> often not sufficient time for the signature of the important population
> splitting events to be recorded in the plants’ genetics, and morphology
> (perhaps obviously in this case) usually presents an equally confusing
> story. The take home message here is that all these various genera
> (Lysimachia, Anagallis, Trientalis, etc.) are very unlikely to really be
> the separate lineages we thought they were. More likely, their histories
> and evolutionary relationships interweave in complex ways.
> The vast majority of modern systematists (a.k.a. taxonomists) place high
> value on producing classifications (a.k.a. taxonomy) that are consistent
> with evolutionary history. The most important reason for this is well
> summed up by the title of a famous paper by Dobzhansky, which is “Nothing
> in biology makes sense except in the light of evolution”. Since taxonomic
> classifications provide the structure upon which pretty much all other
> discussions of organisms depend, it makes a lot of sense to try and make
> the classification match the evolutionary history, so that all the
> dependent discussions also make sense. In the case of Lysimachia, lumping
> all those other interwoven genera into a single generic concept presents a
> view that is more consistent with the evolutionary picture that is coming
> into focus.
> I agree that it is inconvenient when the evolutionary history doesn’t match
> familiar morphological concepts, but that is actually the point of the
> reclassification. It removes the veil from the statue, so to speak, and
> opens your eyes to what’s underneath. In this case, I would suggest that
> the most important conclusion is that “Lysimachia” as you thought you knew
> it, isn’t really the same kind of thing as other familiar genera like
> Narcissus or Calochortus or Galanthus (which to my knowledge, do correspond
> to coherent lineages). In reality, the story of Lysimachia is likely much
> more complex and nuanced than you were led to believe. The reclassification
> is just the mechanism by which systematics has clarified that reality.
> That said, classifications are constantly evolving as new data and analyses
> continue to improve our understanding of the evolutionary history of life
> on earth. Based on the papers I saw, the classification of Lysimachia is
> far from complete. Maybe the next breakthrough in this group will vindicate
> some of your misgivings about the current one. Either way, I think these
> kinds of taxonomic stories are fascinating, since they do such an
> outstanding job of illustrating how much we still have to learn about
> evolution and plant diversity.
> And, Campanula is a mess, isn’t it? If only the main problem faced by
> systematists these days was too much time on their hands. (If it were, I
> might still be one.) Unfortunately, not enough funding (or time for that
> matter) is more of an issue. But considering that it took hundreds of
> millions of years for all this diversity to evolve in the first place, I
> suppose we are doing alright for having been studying it for only a few
> thousand.
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Martin (pronoun: he)
Southern Germany
Likely zone 7a

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