23. Cosmianthemum Bremekamp, Blumea. 10: 166. 1960.
秋英爵床属 qiu ying jue chuang shu
Authors: Jia-qi Hu & Thomas F. Daniel
Herbs, often prostrate then ascending, rarely erect, with cystoliths, isophyllous. Leaves petiolate or subsessile; leaf blade margin entire. Inflorescences terminal thyrsoid racemes or thyrses, sometimes with many-flowered cymes proximally and 1-3-flowered cymes distally; bracts small; bracteoles smaller than bracts. Calyx usually deeply 5-lobed; lobes subequal or slightly unequal, posterior one sometimes shorter. Corolla white, greenish, or yellowish; tube straight or curved, sometimes with a dorsal pouch; throat short or absent; limb 2-lipped; lower lip 3-lobed; upper lip emarginate or 2-lobed [or entire]; lobes ascending cochlear in bud. Stamens 2, inserted at throat; anthers 2-thecous; thecae equal or subequal, parallel, muticous at base; staminodes 2, inserted at base of upper lip. Stigma 2-cleft. Capsule stalked, 4-seeded; retinacula present.
About ten species: SE Asia, especially Borneo; three species (two endemic) in China.
Cosmianthemum resembles Pseuderanthemum in fruit and androecium but differs by the generally smaller corolla being distinctly 2-lipped (the upper lip only shallowly lobed) and lacking an elongate, narrow, cylindric tube; see B. Hansen (Nordic J. Bot. 5: 195-197. 1985) and B. L. Burtt and R. M. Smith (Notes Roy. Bot. Gard. Edinburgh 26: 365-381. 1965).
