A corm is a short, vertical, swollen underground stem of a plant (usually monocots) that stores food reserves to enable the plant to survive winter or other adverse conditions. A corm is typically surrounded by protective skins or tunics. Inside, a corm is mostly starch-containing parenchyma cells. Corms can be dug up and used to propagate or redistribute the plant (see, for example, taro). They are similar in appearance to bulbs, and may be erroneously called by that name.

Cultivated plants that form corms include;

  • Many plants of the Family Iridaceae grown for their flowers, including Crocus, Gladiolus, Iris, and Montbretia
  • Taro and other similar members of the Family Araceae (arums).

  • See also: rhizomes.