81. Oreoloma Botschantzev, Bot. Zhurn. (Moscow & Leningrad). 65: 425. 1980.
爪花芥属 zhao hua jie shu
Herbs perennial, with a distinct caudex. Trichomes dendritic, mixed with stalked glandular ones. Stems erect, simple or branched basally and/or apically. Basal leaves petiolate, rosulate, simple, pinnatifid, pinnatisect, sinuate-dentate, repand, or entire. Cauline leaves few to many. Racemes ebracteate, elongated in fruit. Fruiting pedicels thickened, nearly as wide as fruit, divaricate. Sepals oblong-linear, erect, unequal, base of lateral pair saccate, margin membranous. Petals purple, pink, yellow, or rarely white; blade broadly obovate or spatulate, apex rounded; claw well differentiated from blade, longer than sepals. Stamens 6, strongly tetradynamous; median filaments connate into 2 pair, dilated at base; anthers narrowly oblong, obtuse at apex. Nectar glands 2, lateral, annular or semiannular; median glands absent. Ovules 8-50 per ovary. Fruit tardily dehiscent siliques opening basipetally, not breaking transversely into segments, linear or oblong, terete, sessile; valves corky, not veined, with glandular and/or dendritic trichomes, not torulose or moniliform; replum flattened; septum complete, thickened; style prominent, short, or obsolete; stigma capitate or linear, obscurely to strongly 2-lobed, lobes spreading, free, not decurrent. Seeds uniseriate, wingless, oblong, slightly flattened; seed coat not mucilaginous when wetted; cotyledons incumbent.
Three species: China, Mongolia; three species (two endemic) in China.
Oreoloma, which is almost exclusively Chinese, is most closely related to Sterigmostemum, a genus distributed primarily in SW Asia. It consists of perennials with erect, unequal, basally saccate sepals, large petals, (1-)1.3-2.2 cm, strongly differentiated into a blade and claw, and fruit not breaking transversely into segments. Sterigmostemum comprises mostly annuals with ascending, equal, nonsaccate sepals, smaller petals, 0.5-1(-1.2) cm, undifferentiated into a blade and claw, and fruit generally breaking transversely into segments.