As much as I admire the work done by people like Manning, Goldblatt,
and other experts in this area (such as Alan Meerow), even though I'm
no expert nor do I have college course training in this field, I think
they've pushed the definition of what a species or genus is or is not,
according to DNA analysis, too far. Who decides the cut-off point in
DNA similarity beyond which we will say two different plants are
different species, or different genera? How did these researchers
decide on their metric? Since there isn't any hard and fast definition
about what a Genus is or isn't, but there is this sense that
growers/hobbyists have, analogous to the U.S. Supreme Court justice's
statement about how to determine if something was obscene or not: "I
know it when I see it." (See
<http://law.umkc.edu/faculty/projects/… obscenity.htm>),
it seems that that kind of thing should also be
included in deciding whether a group of plants ought to be given their
own genus name or not. Let us know that they are very closely related
and that we could try hybridizing them. That would be great
information. But I see no reason why they can't remain separate genera
in name, since this is a descriptive term as well as an indication of
some natural relationship. Maybe these DNA researchers ought to
increase the importance of a Supergenus or Subfamily name so that we
all begin to use that category as well as Family, Genus, and Species.

I've already stated on some previous occasion my objections to the
lumping of Homeria, Gynandriris, (and others?) into Moraea and how
every single site that sells these always puts the original genus name
in parentheses next to it because people who grow them still separate
them into different genuses. I do.

With respect to lumping Polyxena into Lachenalia, I grow quite a few
species of Lachenalia and around 5 species of Polyxena. I never confuse
the two and I never get them mixed up. It's great to hear that they are
so closely related and belong to the same supergenus. Maybe there will
be people who try hybridizing the two together. But I would never
consider any Polyxena just another Lachenalia. They're different enough
to not need to be put into the same genus in my opinion.

I'm even more amazed that these experts now consider Albuca, Dipcadi
and Ornithogalum all the same. Why? Once again it's great to hear that
they're all part of the same supergenus and again maybe some
interesting hybrids might appear in the future. But I see no reason why
I should just "lump" all my Albuca species' pots mixed in with all my
Ornithogalum species' pots as if they were all permutations of the same
general genus. I think even my 2-year-old would be able to separate
those two groups from each other when in bloom.

Given the fact that research on the human genome is showing that there
isn't a one-to-one correspondence between a gene on the DNA strand and
a single trait in a human, and that even some of the non-gene parts of
DNA may play important parts in determining the growth and
differentiation of traits in any given organism, it seems a little too
rushed to say that you can do a DNA analysis of only certain
chromosomes or parts of chromosomes of a set of plants and based solely
on the differences in those parts of the DNA be able to adequately
determine quantitatively when two species ought to be classed in the
same genus or not.

If I have to, I'll do the reverse of what the nurseries do and put the
lumped genus name in parentheses on my plant labels next to the
original, and IMHO better, genus name... ;-)
All my opinion, of course.
--Lee Poulsen
Pasadena area, California, USDA Zone 9-10

On Jan 12, 2005, at 8:09 AM, Mary Sue Ittner wrote:

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