Description:

• Lianes or scandent shrubs or small trees, unarmed, occasionally with latex
• Leaves opposite or subopposite, entire or toothed, with petiole often articulated at base; stipules free or united interpetiolarly, caducous
• Inflorescences pedunculate, cymose, dichasial or submonochasial, axillary; often with accessory branches
• Flowers bisexual
• Sepals (4)5, imbricate, more or less free
• Petals (4)5(6), green, white or yellow, valvate or imbricate in bud
• Disc extrastaminal, single or double, conical to saucer-shaped, free or variously united with other floral parts
• Stamens (2)3(4), arising inside disc, usually shorter than petals; filaments broadened below, free or adnate at base or to ovary or gynophore; anthers extrorse, didynamous, (1)2-thecous, with thecae at length confluent; pollen simple or polyads
• Ovary free or confluent with disc, often 3-lobed, 3-locular, with 2-20 ovules in 2 series in each locule; style developed or obsolete, trifid
• Fruit separating into 3 capsular mericarps, connate at base or rarely for most of their length; carpels dorsiventrally flattened or rarely biconvex, dehiscing by median suture or rarely indehiscent
• Seeds with long stalks, rarely sessile, stalk usually expanded into a wing with raphe forming a submedial or marginal vein and thickened integuments forming a vein along other margin; germination epigeal or hypogeal
• x = 14 (polyploidy)

Classification Notes:

• Differences of various segregate genera, mainly applied in tropical America and other parts of the world, are based on somewhat subtle variations in the shape of buds, arrangement of petals and position and shape of the nectar disc
• In Africa distinctions appear less marked. Perhaps the rank of subgenus under Hippocratea should be advocated, but it may well be that the segregate genera Loeseneriella A.C.Sm., Reissantia Hallé, Elachyptera A.C.Sm., Prionostemma Miers and Pristimera Miers will have to be used in southern Africa
• Hippocratea in strict sense comprises only 2 species in tropical America and tropical Africa
• The following key would then be applicable, with the number of southern African species indicated.:

• 1a Flower bud conical; petals valvate or subimbricate in bud >>> Loeseneriella (2)
• 1b Flower bud globose; petals imbricate in bud:
  • 2a Accessory branches in inflorescence absent; ovules 4-20 per locule; seeds 2 or more per mericarp:
    • 3a Petals unguiculate, lamina ovate to subcircular; leaves with prominent reticulate venation >>> Prionostemma (1)
    • 3b Petals not unguiculate, elliptic to oblong; leaves without obvious reticulate venation >>> Pristimera (2)
  • 2b Accessory branches in inflorescence present; ovules 2 per locule; seeds 2 per mericarp:
    • 4a Disc deeply cup-shaped >>> Elachyptera (1)
    • 4b Disc a low pad, narrowly sinuous >>> Reissantia (3)

Nomenclature:

• Hippocratea L.
  • Linnaeus: 1191 (1753)
  • Linnaeus: 498 (1754)
  • Loesener: 226 (1893)
  • Smith: 359 (1940)
  • Ding Hou: 31 (1963) considers this a monotypic American genus
  • Robson: 46 (1965) takes broad view
  • Hallé: 256 (1986) recognise segregate genera
  • Robson et al.: 43 (1994) recognise segregate genera

Distribution & Notes:

• Global: Species ± 120
  • See Classification Notes above