A shoot system (PO:0009006) that has as parts a short, enlarged stem (PO:0009047) in which the shoot internodes (PO:0005005) do not elongate, and one or more buds (PO:0000055).
May serve as a storage or perennating organ. Usually underground. A corm differs from a bulb (PO:0025356) in that it does not have fleshy leaves or leaf bases but usually has scale leaves or remnants of dry leaf sheaths that form a protective covering around it. May bear remnants or scars of detached leaves. Adventitious roots may develop from the base of a corm, and these may be contractile, pulling the corm into the soil. Examples include Gladiolus and Crocus. The pseudobulb of an orchid is equivalent to a corm. A corm is very similar to a rhizome (PO:0004542) with very short sympodial units, although not all corms have sympodial growth.