Hook. f. & Thomson
Description
Thalictrum virgatum Hook.f. & Thomson is a widespread Sino-Himalayan meadow rue ranging from the Himalaya of Nepal, India and Bhutan eastward into south-western and central China; the comparatively large GBIF dataset of 498 occurrences attests to its abundance across the temperate Himalayan belt. It favours moist, shaded forest floors, streamsides, scrub margins and grassy slopes within the temperate to subalpine zone, broadly between 2400 and 4000 m. The photographed plant along the Suli-Khola in West Nepal at about 2800 m, flowering in July, is typical of its monsoon-season anthesis in the cool, humid, well-watered understorey of the moist temperate forest.
The species is a slender, erect, glabrous perennial herb with wiry, virgate stems arising from a short rootstock. The leaves are alternate and two- to three-pinnately compound, the ultimate leaflets small, thin, obovate to orbicular and shallowly three-lobed or crenate. The inflorescence is a lax, few-flowered, diffusely branched panicle or raceme; the small, pendulous flowers lack petals and instead bear four to five petaloid, caducous sepals that are whitish, pink-tinged or purplish. The numerous stamens have slender filaments and conspicuous anthers, giving the open flowers a delicate, dangling aspect. The fruit is a small cluster of stipitate, ribbed achenes.
Thalictrum is a large north-temperate genus of wind- and insect-pollinated petal-less Ranunculaceae, and T. virgatum belongs to the slender-stemmed, lax-panicled assemblage of the Sino-Himalaya. Its delicate habit and nodding pink-tinted flowers have brought it into specialist cultivation as a woodland ornamental. Being widespread, ecologically tolerant and locally common throughout the moist temperate Himalaya, it is of no conservation concern, and like many congeners it contains benzylisoquinoline alkaloids of pharmacological interest.
Author: Hook. f. & Thomson · Sources: POWO (Kew), GBIF, Flora of China, Flora of Bhutan, Annotated Checklist of the Flowering Plants of Nepal, B. A. Lecoyer — Monographie du genre Thalictrum