25. Duperrea Pierre ex Pitard in Lecomte, Fl. Indo-Chine. 3: 334. 1924.
长柱山丹属 chang zhu shan dan shu
Authors: Tao Chen & Charlotte M. Taylor
Shrubs or small trees, unarmed. Raphides absent. Leaves opposite or sometimes markedly anisophyllous and apparently ternate due to reduced internodes grouping 2 leaves at 1 node and an apparently single leaf produced on a single very short axillary branch, without domatia or these few, pilosulous, and rudimentary; stipules persistent, interpetiolar or sometimes shortly united around stem, triangular, acuminate to aristate. Inflorescence terminal on principal branches or on reduced axillary branches, quickly becoming overtopped by growth of 1 or 2 axillary branches thus appearing axillary or sometimes with subtending leaf caducous and then appearing pseudoaxillary, corymbiform, many flowered, pedunculate, bracteate. Flowers pedicellate, bisexual, monomorphic. Calyx limb deeply 5(or 6)-lobed. Corolla white, salverform with tube slender, glabrous inside; lobes 5(or 6), convolute in bud. Stamens 5(or 6), inserted in corolla throat, partially exserted; filaments reduced; anthers dorsifixed, bifid at base, with connective prolonged apically into a short conical appendage. Ovary 2-celled, ovules 1 in each cell on peltate axile placentas; stigma subglobose to ellipsoid, long exserted. Fruit black, drupaceous but sometimes appearing baccate, compressed subglobose to somewhat didymous, fleshy, with calyx limb deciduous; pyrenes 2, 1-celled, with 1 seed, plano-convex to oblate, papery or cartilaginous; seeds medium-sized, oblate or concave on ventral face; endosperm corneous; embryo small; cotyledons ovate; radicle basiscopic.
Two species: Cambodia, China, India, Laos, Myanmar, Thailand, Vietnam; one species in China.
Puff et al. (Rubiaceae of Thailand, 88. 2005) observed that Duperrea pavettifolia is quite variable morphologically and suggested that this genus probably comprises only one variable species.