Full name and orig. publication: Platystemma Wall., Pl. Asiat. Rar. 2: 42 (7 June 1831).
Etymology: From the Greek πλατυς, platys = broad, flat; and στεμμα, stemma = crown, corona, flower garland; the name means that the (short-tubed) corolla has a very flat limb.
Infrafamilial position: Didymocarpoid Gesneriaceae - "Basal Asiatic genera” (Weber 2004).
Description: Small slender herbs with a vertical rhizome. Aerial shoots with a single, sessile, orbicular-cordate, membranous, hairy leaf. Cyme emerging from the leaf axil, peduncle slender, bearing 1 to few flowers, bracteoles very small, sublinear. Sepals free nearly to base, forming a wide, campanulate calyx. Corolla violet, tube short, limb wide, deeply bilabiate, lobes wide-oblong, obtuse. Stamens 4, filaments short, curved; anthers apically coherent; thecae divaricate, apically confluent, dehiscing by a single short slit. Nectary annular. Ovary ovoid, style much longer than ovary, stigma inconspicuous. Capsule ovoid-oblong, splitting loculicidally (+ septicidally?), partially enclosed in persisting calyx.
Chromosome number: 2n = 40.
Type and only species: Platystemma violoides Wall.
Distribution: E & W Himalayas (Nepal, Bhutan, N India), SW China.
Ecology: On shady and damp rocks in valleys or dry cliffs, 2300-3200 m.
Notes: The habit of the tiny plant is most conspicuous, recalling to some degree the much larger Raphiocarpus sesquifolius.
Selected references: A. & D. DC. Prodr. 9: 279 (1845); Wang & al. in Wu & Raven (eds.), Fl. China 18: 284 (1998), reg. rev.; Hilliard, in Grierson & Long, Fl. Bhutan 2(3): 1323 (2001), reg. rev.
Bibliography: See Skog, L.E. & J.K. Boggan. 2005. Bibliography of the Gesneriaceae. 2nd edition: http://persoon.si.edu/Gesneriaceae/Bibliography.
Platystemma violoides Wall., type and only species
Wang et al., Fl. reipubl. pop. Sin. 69, t. 58 (1990); with permission.
last modified: 2007-07-13