Underground stem

Different forms of underground stems include: • Bulb - Short, upright organ leaves modified into thick flesh scales. Tulips, daffodils and Lilies. • Corm - Short, upright, hard, or fleshy stems covered with thin, dry papery leaves. • Rhizome - With reduced scale-like leaves. The top can generate leafy stems while the bottom can produce roots. Iris and many grasses. • Stolon - Horizontal stems that run at or just below the soil surface with nodes that root and long internodes, the ends produce new plants. When above ground they are called "runners". • Tuber - An enlarged fleshy end of a stem, generally from rhizomes but often also referring to thickened roots. A number of underground stems are consumed by people including; onion, potato, ginger, yam and taro. The below-ground stems of grasses have scales, while roots are smooth without scales. ==Geophyte==

A geophyte (earth+plant) is a plant with an underground storage organ including true bulbs, corms, tubers, tuberous roots, enlarged hypocotyls, and rhizomes. Most plants with underground stems are geophytes but not all plants that are geophytes have underground stems. Geophytes are often physiologically active even when they lack leaves. They can survive during adverse environmental conditions by going into a state of quiesce and later resume growth from their storage organs, which contain reserves of carbohydrates and water when the environmental conditions are favorable again. ==References==