Description:

• 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

Nomenclature:

• Harpagophytum DC. ex Meisn.
  • Meisner 1: 298 & 2: 206 (1840)
  • Stapf: 457 (1904)
  • Henderson & Anderson: 298 (1966)
  • Ihlenfeldt: 43, t. 8 (1967a)
  • Ihlenfeldt: 600 (1967b)
  • Merxmüller & Schreiber: 4 (1968)
  • Ihlenfeldt & Hartmann: 15 (1970)
  • Verdoorn: t. 1853 (1982)
  • Ihlenfeldt: 109, 111 (1988)
  • Hargreaves: 145 (1993)
  • Ihlenfeldt: 1063 (1994)
• Uncaria Burch.
  • Burchell: 536 (1822) name illegitimate, not of Schreb.

Distribution & Notes:

• Southern Africa: Species 2, widespread mainly in warm, dryish areas of Namibia, Botswana and N South Africa but extending as far south as Pretoria (Gauteng), Barberton (Mpumalanga) and Bloemfontein (Free State)
  • Also Madagascar