WELWITSCHIACEAE

Tumboa (Welwitschia mirabilis) a family of southwestern African desert plants in the order Gnetales, named for its single genus, Welwitschia. Tumboa plants (W. mirabilis or W. bainesii), constituting the only species, have deep taproots and resemble giant radishes, 60 to 120 cm (about 25 to 50 inches) in diameter and projecting about 30 cm (12 inches) above the ground. From the base of the cone-shaped trunk, two broad, flat, straplike leaves grow throughout the life of the plant (100 years or more) but are kept about 3 m (nearly 10 feet) in length by erosion at the tips. The male and female flowers are carried in scales of scarlet cones that grow in a ring above the leaves. In the male flower is a female flower component, an ovule. Although the ovule is rudimentary and abortive in Welwitschia, its presence suggests a hermaphroditic condition more typical of angiosperms.