besseae/dalessandro
Robert,
The main criterion on which
P. dalessandroi has been based as a separate species is the difference in chromosome count. All other differences could be fairly easy explained away. Now, I do know that plants within a species can have different chromosome counts (for example in
Tolumnia guianense, I have counted myself 40, 41 and 42)
It is Interesting that Wimber in 1994 put
P. besseae var.
dalessandroi as having been counted with
28 chromosomes just as
P. besseae itself, and talks of a
"Peruvian besseae" with 24 chromosomes.
Dodson & Gruss argue that
P. besseae always has 24 chromosomes. But that is contradicted by the Wimber counts of tetraploid
P. besseae with 56 chromosomes (56/2 = 28).
Having known Wimber, and having seen the pictures of his publication, I doubt that he made a mistake.
Furthermore, it is known that
P. dalessandroi and
P. besseae cross freely, and I must tell you that it is impossible to know how many artificially bred
"P. besseae" out there are in fact a cross between the two. And only the gods know what has been used to "create" the
"P. besseae" hybrids that are so popular.
Thus for me, the arguments pro "single species"
(P. besseae) are better than those supporting two different species. In Chriron, Chiron & Braem (2006) we included DNA material of 3 different wild collected
besseae and from 1 wild collected
dalessandroi (I don't care if someone screems "bad boy"). The results show that
dalessandroi and
besseae are
very, very, very closely related.
But then, the same applies for
P. schlimii and
P. fischeri.
Beware, the publication is in French and Dodson & Gruss's publication is in German.
I know from "well-informed" sources that 1) the distribution areas of "true
besseae" overlap with those of
P. dalessandroi and that (2) there is distinct variation within "true
besseae". The pollination syndrome is very similar and may well be the same seen through the eyes of an insect. Therefore "intermediates" do not surprise me at all.
Guido
Drorchid said:
OK Guido and Olaf,
I have a question for the both of you. I don't know if you have been following the threads regarding the discovery of Phrag. besseae and the IN-SITU pictures of Phrag. besseae by Kyle.
Anyway my question for you is: do both of you think that Phrag. dalessandroi is distinct enough form Phrag. besseae to warrant it to species rank? And if you consider it to be a different species what characteristics make it different enough from Phrag. besseae to consider it to be a different species.
In my opinon Phrag. dalessandroi should not be considered a species, but a variety (or subspecies) of Phrag. besseae. I think Phrag. besseae is a highly variable species, and that what some people call Phrag. dalessandroi it just one of the "extreme" populations within the species of Phrag. besseae.
If you look at Kyle's pictures, and also the plants that Jerry collected in Peru in the 80's they show charcteristics that are intermediate between Phrag. besseae and Phrag. dalessandroi. Some people would call these natural hybrids between Phrag. besseae and Phrag. dalessandroi, but I would call them "intermediate" populations of Phrag besseae that show charcteristics of the true Phrag besseae (of what is considered to be the "type" of Phrag. besseae) and Phrag. dalessandroi. Also if you have these "intermediate" populations or natural hybrids, is this not proof that you have gene flow going on from one population to another (or as some people would say form dallesandroi to besseae) and as you have gene flow going on this would be a reason to lump them all in the same species: Phrag. besseae.
Robert
Thanks for your expertise!
