Plectronia
(from plektron, a cock's spur; in allusion to the large spines which are to be found on some of the species). SYNS. Canthium, Dondisia, Mitrastigma, Phallaria, Psilostoma, Psydrax. ORD. Rubiaceae. A large genus (about seventy species) of stove or greenhouse, unarmed or spiny, shrubs, sometimes climbing, with terete branchlets; they are natives of tropical Asia, Africa, and Australia, South Africa, and the Pacific Islands. Flowers white or greenish, small, fascicled or disposed in corymbose, pedunculate cymes; calyx with a short tube, and a very short, truncate or four or five-toothed limb; corolla tube short or slightly elongated, with four or five ovate-triangular lobes. Fruit small or mediocre. Leaves opposite, membranous or coriaceous, shortly petiolate, oblong, ovate, or lanceolate; stipules intrapetiolar. Few of the species have been introduced, and none are important horticulturally.