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Re: Extinct

I beg to differ. Plants that are grown from vegetative propagation do have
genetic drift, granted far less than the variation you would see from seed
raised plants but in some cases significant variations. Especially in the
case of a fast growing herb where a slight modification in the genes of one
branch that gave it an edge in growing under the specific conditions it is
raised in can mean that the whole colony eventually is descended from that
one small branch. Ever had Micranthemum melt? Often it is only one or two
branches that remain. These may be slightly different genetically than the
rest of the plant, but if they remain viable can quickly gain the same mass
as the original plant. That difference may be multiplied over time, as it is
propagated from one aquarium to another, and can mean a distinct difference
in the gene-pool from the original plant. Is this enough to disignate it as
a new species? Probably not. But it is certainly enough to make it
unsuitable for the ethical inclusion in habitat restoration where the
provenance of a plant is very important for the integrity of the project, if
for no other reason than few if any of the plants in the aquarium trade have
a known provenance. You may find this silly, but there are plenty of cases
where a plant from Massachuesets was planted in a restoration project in
Washington 'because the species was right'. Personally I think if we are
going to take the time to restore a habitat, it makes sense to restore it
from genetic material appropriate to the site, not from just anywhere.

I have to say, though, judging by how it grows in my tank (fairly high light
but no CO2), I'm surprised its not a marginal weed in its native habitat.
Assuming I have the same species, of course... I don't have a key to check
the identity, or flowers for that matter.

Brett Johnson
Green Man Gardens
bnbjohns at attbi_com

Date: Sat, 23 Mar 2002 08:10:19 -0600
From: krombhol at teclink_net (Paul Krombholz)
Subject: Re: Extinct

Since Hemianthus micranthemoides is so easily propagated vegetatively, I
doubt that any aquariasts are propagating it by seed.  Assuming that it is
not being reproduced in culture sexually, but rather asexually, its genetic
make-up is going to remain essentially unchanged over the time it has been
in the aquarium trade.  Thus, I argue that it could still be returned to
its natural habitat and have a good chance of re-establishing itself,
provided that such natural habitat still exists.  it seems like a pretty
tough little plant to me, and I am pretty sure I saw it growing emersed in
a gravelly area at the edge of Black Creek in the Desoto National Forest.

If any one were trying to re-establish it, they would not have to worry
about it having been changed to the point where it could no longer survive
in the wild.  Just look at how Hygrophila polysperma has become a noxious
weed in some southern rivers.  I read somewhere that it is even crowing out
Hydrilla, and that takes some doing!

Paul Krombholz in chilly central Mississippi, where last night's freeze was
lighter than expected.