(Hook.f. & Thomson) W.T.Wang & P.K.Hsiao
Description
Dichocarpum adiantifolium is a slender woodland buttercup relative of the Sino-Himalayan region, distributed through Taiwan, China, India, Nepal, Bhutan and Myanmar, with the comparatively rich total of about 286 GBIF records. It grows in cool, shaded, humus-rich situations: moist temperate forest floors, mossy rocks, ravine banks and streamsides, generally between about 2000 and 3500 m. The collections illustrated, from Honggaon in Nepal at around 2300 m and Tonglu in West Bengal at about 3200 m, both in May, represent its typical spring-flowering forest habitat.
It is a delicate, glabrous perennial herb arising from a short rhizome. The leaves are mostly basal, long-petiolate and compound, divided into numerous small, thin, fan-shaped to obovate leaflets that recall the fronds of a maidenhair fern (Adiantum), hence the epithet. Slender scapes bear loose, few-flowered cymes of small flowers, each with five white, petaloid sepals and small tubular or two-lipped nectary petals, numerous stamens and usually two carpels. The diagnostic fruit is a pair of divergent, flattened follicles spreading widely at maturity, a feature reflected in the generic name (from the Greek for divided fruit).
Dichocarpum is a small east Asian and Himalayan genus segregated from Isopyrum and allied to Thalictrum and Aquilegia within the Ranunculaceae; D. adiantifolium was originally described under Isopyrum and later transferred by Wang and Hsiao. The paired spreading follicles and ferny foliage make it readily recognisable. It is a fairly widespread forest-understorey species and is not regarded as threatened, though as a shade-demanding mesophyte it depends on intact, humid temperate forest and would be sensitive to logging and forest fragmentation.
Author: (Hook.f. & Thomson) W.T.Wang & P.K.Hsiao · Sources: POWO (Kew), GBIF, Flora of China, Flora of Bhutan, Annotated Checklist of the Flowering Plants of Nepal, Wang & Hsiao Revision of the Genus Dichocarpum