酸脚杆属 suan jiao gan shu

Pseudodissochaeta M. P. Nayar.

Small trees, or erect or scandent shrubs, terrestrial, epiphytic, or rarely climbing. Stems 4-sided or terete, sometimes succulent or corky. Leaves opposite or verticillate, petiolate or sessile; leaf blade usually glabrous, margin entire or dentate. Inflorescences terminal or axillary inserted on leafless stems or at nodes of root stock, cymose or cymose paniculate; bracts small, caducous. Flowers 4(-6)-merous, pedicellate and sometimes bracteolate. Hypanthium cup-shaped, funnel-shaped, campanulate, or tubular. Calyx lobes conspicuous or inconspicuous, apex apiculate. Petals obovate, ovate, or suborbicular, sometimes oblique. Stamens 2 × as many as petals, whorls equal or slightly unequal in shape and length; anthers linear, lanceolate, or oblong, base tuberculate or appendaged, apex beaked, dehiscent by a single pore; connective slightly decurrent forming a spur. Ovary inferior, ovate, apex truncate or with a membranous crown, sometimes septate. Berry globular, ovate, or often urceolate, apex indehiscent. Seeds numerous, obovate to shortly cuneate, small, glabrous or tuberculate.

Between 300 and 400 species: tropical Africa, Asia, and Pacific islands; 11 species (five endemic) in China.

In China Pseudodissochaeta has been treated as a synonym of Medinilla (the species concerned are M. assamica, M. lanceata, and M. septentrionalis), whereas Pseudodissochaeta has also been treated as a separate genus (Fl. Thailand 7(3): 475. 2001). Unpublished molecular data indicate that at least M. septentrionalis (P. septentrionalis) is not close to Medinilla. The fact that the Melastomataceae specialists W. W. Smith, H. L. Li, Kraenzlin, Guillaumin, Nayar, and Chen Cheih allocated the three Chinese species of Pseudodissochaeta to six different genera (Allomorphia, Anplectrum A. Gray, Diplectria, Medinilla, Oritrephes Ridley, Pseudodissochaeta) indicates the difficulty of determining their true affinities from morphological data. Additional molecular data are needed to resolve the problem.