Plant Propagation Technique
Corms are solid objects, usually quite firm, instead of being formed of layers or scales like a true bulb. The method of growth is also entirely different. A true bulb may live indefinitely as a single unit or may increase by splitting itself up, but a mature corm actually withers and dies after a year of growth, being replaced by a new corm or corms that form on top of the old one but sometimes beneath or alongside it.
A corm is a shortened, fleshy, erect underground stem with inconspicuous scale-like leaves. It closely resembles, and is often mistakenly identified as, a bulb (as the "bulbs" of Gladiolus and Crocus), but actually it is distinguished by being more accurately a modified stem.
The stem character of bulbs is obscured by their very fleshy leaves. From the prominent terminal bud and smaller ones in the axils of its scale-like leaves, corms develop new plants, and often small, subsidiary corms known as cormels. Gladiolus, Freesia, Tritonia and Caladium all grow from corms.
Corms are frequently used to propagate a plant by digging them out of the ground, then cutting the corms into individual sections and replanting. Each section of the corm that has at least a single bud can usually generate a new corm.
Propagation by Corms Articles
Fall Storage of Tender Bulbs, Corms & Tubers
By Sherry Rindels, Department of Horticulture
Iowa State University, Ames, Iowa.
Planting and Care of Bulbs, Corms, Rhizomes, and Roots
By Mississippi State University Extension Service (Adobe PDF)