Corm: Understanding This Underground Stem

Like a true bulb, a corm is a stem base—but its tissue is solid, without scales. Roots grow from a basal plate at the bottom; the growth point is at the top. Gladiolus and crocus are two familiar corms.

Each corm lasts a single year. As it shrinks after blooming, a new corm forms on top; many small increases, called cormels, may also be produced around the new corm's basal plate.