71. Porterandia Ridley, Bull. Misc. Inform. Kew. 1939: 593. 1940.
绢冠茜属 juan guan qian shu
Authors: Tao Chen & Charlotte M. Taylor
Randia sect. Anisophyllea J. D. Hooker, Fl. Brit. India 3: 113. 1880.
Shrubs or trees, [sometimes dioecious], unarmed. Raphides absent. Leaves opposite, sometimes anisophyllous, sometimes with domatia; stipules persistent, interpetiolar to shortly united around stem, triangular. Inflorescences pseudoaxillary [or terminal], cymose to thyrsiform, few to several flowered, pedunculate, bracteate. Flowers sessile to pedicellate, bisexual [or unisexual]. Calyx limb well developed, 5-lobed. Corolla white, salverform, outside densely sericeous, inside variously glabrous or pubescent; lobes 5(or 6), convolute in bud. Stamens 5, inserted in upper part of corolla tube, included or partially exserted; filaments very short or absent; anthers dorsifixed. Ovary 2-celled, ovules numerous in each cell on axile placentas; stigma clavate or fusiform, bifid, striate, included or perhaps exserted. Fruit perhaps yellow to brown, baccate, fleshy to woody, subglobose or obovoid, with calyx limb tardily deciduous; seeds numerous, medium-sized, ellipsoid or reniform, flattened, embedded in pulp.
About 22 species: S and SE Asia, Pacific islands; one species (endemic) in China.
Formerly several African species were included in Porterandia, but these have separated as Aoranthe Somers (see Somers, Bull. Jard. Bot. Natl. Belg. 58: 47-75. 1988). Puff et al. (Rubiaceae of Thailand, 64. 2005) reported that the calyx limb is persistent in fruit in Porterandia, but their own figure seems to show it deciduous; on herbarium specimens of various Porterandia species the calyx limb appears to fall as the fruit approach mature size. W. C. Chen (in FRPS 71(1): 386. 1999) reported that the corolla lobes are rarely 6, but this number has not been reported by other authors; it is not clear if this number is consistent or is a report of infrequent unusual flowers, which occurs periodically in many species of Rubiaceae. W. C. Chen and Puff et al. described the stamens and stigmas as included, but they are shown as exserted in Chen’s figure (loc. cit.: 385, t. 101). W. C. Chen (loc. cit.: 384) also described the ovary as incompletely 4-celled, but no other authors have reported this.