Re: 23 species or less?
- Subject: Re: 23 species or less?
- From: h*@open.org
- Date: Sat, 2 Mar 2002 19:38:14 -0800 (PST)
George:
>Flower morphology indicates that there may (originally) have been a
>half dozen good species which have been shuffled around over the last
>millennium.
I'm not a hosta expert and I'm not a taxonomist by training, but I do
understand the factors involved in what constitutes a species. I also
tend to be a clumper rather then a splitter.
When I look at hosta flowers I really don't see a lot of differences
when compared to some of the differences I see in the genera I am more
familiar with. There is some differences in size and the distribution
of flowers along the scape. In regards to color you have either white
or some variation of purple/lavender. While there is a lot of
difference in the foliage of different hostas in terms of size and
shape, it would be questionable to seperate species based mainly on
foliage traits as these traits are controlled by relatively few genes.
This phenotypic buffering is what you would expect in an
amphidiploid. A serious study of hosta species would have to be based
on geographic distribution, breeding behavior and genetic and
molecular traits in addition to any phenotypic data.
Ben's DNA data is interesting, but his error level is so high that it
only becomes useful when the hostas in question have a high difference
in their DNA content. If one population has a DNA conent of 26 or 27
pg and another has a DNA content of 31 or 32, then you can say the DNA
data has some significence. Ben's DNA data is valuable, but it has to
be taken with a BIG grain of salt.
>In the populations I have field-investigated a high degree of
>fertility seems to have been maintained.
Amphidiploids tend to be fertile as long as the parents are fertile,
because each chromosome has a corrsponding chromosome to pair with.
The interesting question is how an amphidiploid population becomes
established. If there is only one amphidiploid individual created,
then it has to be self-fertile to some degree in order to establish
itself.
Joe Halinar
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