Re: setosa, hookeri, tridentata, var. canandensis and var. arctica

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Dear Tom;

 

I think it can be fairly stated that the real understanding of the three species included in the tripetalae is very poor. For the time being I would definitely separate Iris hookeri from Iris setosa. It seems rather pretentious to reduce it to synonymy when all the studies that have looked at it rather closely, indicate there are very distinct chemical differences. Unfortunately the gross morphology is similar. Of course if one is less sophisticated and goes only by the fact that the petals may in some forms be reduced to bristles, one could make the stupid mistake you can find on the USDA website, showing a picture of Iris danfordiae as Iris setosa. The point I would make is that reduced standards are not expecially special. Iris pseudacorus in some forms has very reduced standards. One has to understand how the plants function in nature. It has been postulated that Iris tridentata, chromosomes =40 may be more closely related to Louisiana irises. A fact I have been trying to get across is that the average gardener could add significantly to our species knowledge by growing species such as these side by side and making careful observations. Just discovering the hardiness range of tridentata to the North .or setosa to the South. would tell us some things. Of course these notes are meaningless unless they are published in an accessible place. This is why I continually ask for observations on flower size, branching, bloom times, etc. to put into the checklist. The more information that can be developed the better the conclusions will be that future generations will live by. Despite the capabilities of modern science a lot of basic information is still poorly documented. At the moment I suspect these three species are very distinct, but I could not give definitive characters to separate them

tesilvers <tesilvers@yahoo.com> wrote:

setosa, hookeri, tridentata, var. canandensis and var. arctica

Could someone shed some light on the current taxonomic view of these
irises? For instance, I seem to remember something about I.
tridentata once being considered a geographically isolated population
of setosa? And that the northeastern North American population of
setosa, used to be called I.setosa var. canadensis, but is now maybe
considered separate enough to be called I. hookeri. Does the
population of setosa form a continuum, (from Asia through western
North America to eastern North America) which grades from one type
into another? Or are there discrete blocks of the types? And what are
the distinguishing features of the types? For example, how would you
tell a tridentata from a hookeri from a setosa var arctica?

I'm mostly wondering how varied the setosa clan is and how
interfertile these various members are? And are they all 2n=38?