Re:  Tubers, corms and bulbs, oh my!
- Subject: Re:  Tubers, corms and bulbs, oh my!
- From: Ken Mosher <firstname.lastname@example.org>
- Date: Sat, 06 Feb 2010 18:42:14 -0500
Thanks, Christopher. I always called them tubers but thought that they
were more correctly called corms. I thought that because a botanist
friend of mine said they were corms.
Christopher Rogers wrote:
> I recently had a discussion with few Aroid Oriented Individuals about
> proper terminology for the non-root, subterranean aroid parts. Or to
> put it another way, do plants like Amorphophallus, Arum,
> Helicodiceros, Typhonium, Colocasia, Ambrosina, and the like have
> tubers, corms or bulbs?
> The answer is that they have tubers. (Or for dear Julius' sake,
> A bulb is composed of thick, modified leaves, arranged in layers, for
> food storage. An onion is a perfect example.
> A corm is composed entirely of stem tissue. It is literally just an
> underground stem. It has an epidermal layer, a vascular cylinder with
> phloem and xylem and central pith. A corm can also be a starch storage
> organ, but it still has true stem tissue. This is why a corm has the
> new foliage growth coming from the top and the roots coming from the
> base. Corm examples are Crocus, Cyclamen and Gladiolus. A cormel is
> just a diminutive corm.
> A tuber is just parenchyma (with some vascular tissue). It has an
> epidermal layer with some subdermal vascular tissue, and all the rest
> is parenchyma. It is almost entirely a starch storage organ. This is
> why the foliage and the roots all come from the top. Most plants with
> tubers have them borne on stolons, but that is not necessary. In
> Amorphophallus, Arum and Typhonium for example, the stem tissue is all
> encased in the small bud at the top of the tuber. That bud grows
> upward into a leaf or two, and outward into roots, with the tuber
> beneath. Other tuber examples are potatoes and Sinningia.
> A bulbil, in the aroid sense, is just a tuber that forms on leaves or
> leaf axils. It is an unfortunate term as it obviously leads to confusion.
> I really hope that this is helpful to the Aroid community at large,
> and I hope it cuts down on some of the confusion surrounding these
> terms. I am sure Pete, Wilbert, Tom, Julius, The Banta or someone can
> elucidate further, particularly as far as tuberous rhizomes or
> rhizomatic tubers are concerned.
> Happy days,
> D. Christopher Rogers
> Senior Invertebrate Ecologist/ Taxonomist
> *EcoAnalysts, Inc.*
> P.O. Box 4098
> Davis, CA 95616
> Invertebrate Taxonomy
> Endangered Species
> Ecological Studies
> Invasive Species
> *IDAHO ∙ CALIFORNIA ∙ MISSOURI ∙ PENNSYLVANIA ∙ VANCOUVER*
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