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Re: Amano Pearl Grass

> Date: Wed, 20 Dec 2000 18:08:53 -0500
> From: Neil Frank
> From: Dwight
> >
> >Hemianthus umbrosum is what I've seen being sold as
> >"Baby tears".   It is the more demanding plant.   I identify
> >it b/c it has 3-4 leaves at each joint. I am told it is an
> >American var.
> H. micranthemoides also has 3-4 leaves per node and it
> too is native to America.  It's leaves are similar in size to
> the other Hemianthus species (aka "pearl grass").
> Umbrosum has larger leaves unless the plant is starved
> of macronutrients.

There appears to be a difference in the shape of the leaves as well as their
size - at least in my tanks. _Micranthemum umbrosum_ has larger, more
*ovate* leaves than _Hemianthus macranthemoides_. The smaller
macranthemoides leaves are more longitudinally stretched, approaching a
blunt lanceolate form.

Umbrosum's leaves also grow thicker and more blunt at the stem junction, and
appear to lack a visible petiole. This makes it seem as though the leaf is
"butted" up against the stem. Macranthemoides leaves narrow sharply to the
petiole to give it visual separation from the stem.

> >I have chosen to identify them both as Hemianthus
> >micranthemoides and specify their common names so
> >folks know they are two distinct & DIFFERENT plants.
> Arbitrarily assiging species names to a plant is not good practice and,
> unfortunately contributes to the confusion regarding the identity of
> aquarium plants. This has been done by most sellers of aquatic plants over

Neil beat me to the punch on this one, so it may sound like "me too!", but
on this issue I have _definite_ objections.

Dwight, I really fail to see how your approach will do anything to alleviate
confusion over the plants in question. You may as well take the "lumping"
tack to taxonomy to its extreme by eliminating species altogether, as that
seems to be where most of the "confusion" lies in these sorts of questions.

Rather than try to explain all of the reasons it _wouldn't_ be such a good
idea, I'll wait until I hear from you on why you think it _would_, though.
Rebuttal is much more productive than idle rambling.

And notice that I'm still separating more than just species, here - but
that's _another_ issue...


David A. Youngker
nestor10 at mindspring_com

...who _really_ doesn't relish the thought of a "Reader's Digest Condensed"
form of a taxonomic lexicon...