Harpagophytum

Perennial, trailing herbs with several annual stems from a succulent, often tuberous taproot, further tubers often present on lateral roots; whole plant +/- glabrous but covered with mucilage glands. Leaves opposite, shortly petiolate, variable in shape and often polymorphic, subsucculent, usually pale beneath because of white glands. Flowers solitary, axillary, shortly pedicellate, erect; white or yellow and pink, mauve or purplish red, usually with light tube and darker limb. Calyx much shorter than corolla tube; segments sometimes unequal, glandular-hairy. Corolla: tube +/- cylindrical or narrowly funnel-shaped, basally constricted; limb spreading; lobes subequal, circular to oblate. Stamens didynamous or +/- equal, included; anthers with thecae divergent, apiculate; staminode 1, with apical gland. Ovary 2-locular with no false septa; ovoid or elliptical, sometimes nodulose; ovules many, in 2 or 4 rows in each locule; style terete, included; stigma of 2 ovate, membranous lobes. Fruit a woody, 2-locular capsule, laterally compressed at right angles to septum, with 2 obtuse protuberances on each face and armed along edges with 2 rows of curved, horny arms, each bearing recurved spines, or edges with 2 rigid wings bearing recurved spines; tardily and imperfectly loculicidal. Seeds many, narrowly obovate, unevenly angled, black; testa irregularly reticulate.