Male and female flowers are borne separately on the same plant, and require insects for pollination. Flowers are borne singly in the leaf axils. Male flowers appear first and usually exceed the number of female flowers by about 25 to 1. The flower opens at sunrise and remain open for only 1 day. The fruits are characterized by a pebbly surface of smooth warts and smooth lengthwise ridges.
Immature fruits are light green, oblong, pointed at the blossom end and have white flesh.
As the fruits begins to mature, the surface gradually turns yellow or orange. At maturity, it tends to split open, revealing orange flesh and bright red placenta which the seeds are attached. The probable place of origin of bitter melon is either China or India Other names. Market Information Marketing. In 1988 at the San Francisco wholesale market bittermelon supplies came primarily from Mexico from December through March.