Tropical tree (Ficus elastica) of the mulberry family. The rubber plant is large in its native Southeast Asia and other warm areas; elsewhere it is commonly grown indoors as a potted plant. The plant has large, thick, oblong leaves and pairs of figlike fruits along its branches. The milky sap, or latex, was once an important source of an inferior natural rubber. Young plants available in the florist's trade are durable and grow well under less than ideal indoor conditions. Some cultivated varieties have broader, darker green leaves; others are variegated. See alsorubber tree.