Harpagophytum DC. ex Meisn.

Pedaliaceae, H. D. Ihlenfeldt. Flora Zambesiaca 8:3. 1988

Habit

Perennial herb with several prostrate annual stems from a succulent tuberous taproot, additional tubers often present on lateral roots; whole plant glabrous or subglabrous and covered with mucilage-glands.

Leaves

Leaves opposite, subsucculent, petiolate, very variable in shape and often polymorphic.

Flowers

Flowers solitary, shortly pedicelled, erect; corolla tube nearly cylindrical, constricted at the base; limb spreading; lobes of limb subequal, circular to oblate; corolla tube light purple, pink, yellow or white outside, usually more or less yellow inside; limb purple or mauve, occasionally yellow.

Stamens

Stamens 4, included, inserted near the base of the corolla tube; thecae divergent; staminodium present, with apical gland.

Ovary

Ovary bilocular; false septa absent.

Fruits

Fruit a woody capsule, tardily loculicidally imperfectly dehiscent, laterally compressed, with two obtuse protuberances on each face, armed with two rows of curved arms along the edges each bearing recurved spines or the edges with two rigid wings bearing recurved spines; mature fruit easily detachable (forming a “trample burr”).

Seeds

Seeds numerous, spreading, in 2 or 4 rows in each loculus, narrowly obovate in outline; testa irregularly reticulate, black.