What is a succulent - was Schizobasis intricata

Hannon othonna@gmail.com
Wed, 20 Aug 2008 10:19:06 PDT
Dear Jim,
You write "In other words, the question which most of us ask, "what's the
between a bulb and a corm", is the wrong question. All bulbs contain a corm;
all bulbs are built around a corm, using corm in the broad sense of stem

Scouring various glossaries and botanical dictionaries it is remarkable to
find that there is little clarity or consensus on the definition of "corm".
If "corm" is only defined as being stem tissue then there is no boundary
between tuber and corm or thickened stem, etc.

The key aspect of a corm, in my view, is that it is renewed annually and
therefore is modular. Examples are many irids such as Gladiolus, Crocus,
etc., and certain "tuberous" aroids like Amorphophallus. In fact, in the
last genus one can find a sort of continuum from 'primitive' rhizomatous
species to strictly modular cormous species that regenerate a perennating
organ each season. There are other taxa that indicate a transition, as in
Tecophilaeaceae: Conanthera (annually renewing corms) and Cyanastrum (corms
that are perennial). Even some geophytic begonias (e.g. B. biserrata) have
what can be called corms.

Dylan Hannon

On Wed, Aug 20, 2008 at 7:46 AM, James Waddick <jwaddick@kc.rr.com> wrote:

> >Aren't most bulbs/corms/tubers water (as well a other things)
> >storage organs, and so technically succulent?
> Dear Tim,
>        Off hand I'd think so without getting into technical
> discriminations especially since we/PBS tend to include a wide range
> of plants with storage organs - rhizome, thickened roots, tubers
> etc....and we often PUSH the limits by including all of a genus when
> only a few qualify.
>        The thing with caudex forming plants is that many/ some? only
> show this enlarged storage stem (usually) if they are planted
> abnormally high and above their 'natural' soil level. I suppose that
> might include a true bulb growing with the majority exposed (Boweia
> for a recent example).
>        So some bulbs are routinely included in succulent shows and
> some plants with water storage organs are planted to expose this
> feature in succulent shows, but there are surely exceptions and lots
> of limits.
>        For example Leeks versus onions. Both in the same genus, the
> former neither succulent nor bulbous, the latter both (some might
> disagree).
>        Others can add 2 cents worth.                   Best            Jim
> W.
> --
> Dr. James W. Waddick
> 8871 NW Brostrom Rd.
> Kansas City Missouri 64152-2711
> Ph.    816-746-1949
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