Characterised by Corm shaped bulb or rhizome. A number of species replace corms every year by growing a new corm. Members of this family are perennial plants, with a bulb, corm or rhizome. "Crocus sativus" has a corm, which holds leaves, bracts, bracteole, and the flowering stalk. Under short-daylength conditions, the rhizomes grow downward and produce a corm at the tip. The dried corm of the konjac plant contains around 40% glucomannan gum. They are perennial plants growing from a fibrous corm, roughly spherical in shape. As the plants grow and flower, they use up the old corm, which shrivels away. Glucomannan comprises 40% by dry weight of the roots, or corm, of the konjac plant. People usually consume its edible corm and leaves. It is a perennial herb growing from a corm. The new corm that replaces the old corm grows in size, especially after flowering ends. Its leaves, corm and seeds are poisonous. The fresh corm is cooked like potatoes before eating. The plant can be propagated from seeds or by division of the corm.