corm; was RE: Late fall in Maryland
Russell Stafford, Odyssey Bulbs (Mon, 14 Dec 2009 09:31:54 PST)
A corm is by definition a condensed, typically narrow stem comprising
several nodes and surrounded by a fibrous tunic. It is
annual/biennial, developing at the apex of the previous year's
corm. Tubers are fleshy annual/biennial structures, which can
comprise either stem or root tissue, and which do not have a
tunic. Stem tubers often form at the tips of stolons. Tropaeolum
storage organs are fleshy, have nodes, and lack tunics, so they are
properly termed stem tubers. Tuberous begonias grow from a perennial
structure that is in effect a modified hypocotyl. Technically it is
neither a corm nor a tuber, although it is usually called the latter.
Russell
At 11:13 AM 12/14/2009, you wrote:
I looked both terms up in the glossary of John Bryan's "Bulbs" revised
edition. I don't always blindly trust John, but he did have help putting
that volume together.
Corm -- underground storage organ, a swollen part of an underground stem
Tuber -- underground root modified as a storage organ.
Russell Stafford
Odyssey Bulbs
PO Box 382
South Lancaster, MA 01561
508-335-8106
http://www.odysseybulbs.com/