(D.Don) C.B.Clarke
Description
Swertia purpurascens is a Himalayan gentian distributed across Nepal, India, Pakistan, Afghanistan, Bhutan and adjacent China, with around 322 occurrences recorded in GBIF. It grows on open grassy slopes, in subalpine scrub, along forest margins and in moist montane meadows, generally between about 1800 and 3600 m. The individual illustrated below the Rupien La in Nepal at 3100 m, flowering in October at the close of the monsoon, reflects the species' characteristic late-season phenology, when many Himalayan swertias bloom on rain-moistened upper slopes before the onset of cold and the senescence of the herb layer.
The plant is an erect annual or short-lived herb 20–80 cm tall, with a slender, four-angled, often branched stem arising from a thin taproot. The leaves are opposite, sessile or shortly petiolate, lanceolate to ovate-lanceolate, three- to five-nerved and entire-margined. The inflorescence is a lax, narrow panicle of numerous flowers. Each flower is typically four-merous, the corolla rotate and divided nearly to the base into lobes that are pale purplish to greenish, often purple-tinged or veined, each lobe bearing one or two nectary pits fringed with characteristic fimbriae. The four stamens alternate with the corolla lobes, and the superior ovary develops into a many-seeded septicidal capsule.
Swertia is a large genus of the Gentianaceae centred on the Sino-Himalayan region, where it has radiated extensively, and the nectary fimbriae of the corolla provide key diagnostic characters separating its species. The nomenclatural history of this taxon is entangled with that of S. ciliata, with which it has frequently been confused; the source page links it to that name, but POWO and GBIF treat S. purpurascens as the accepted entity. As with other swertias, the plant has a reputation in Himalayan ethnomedicine as a bitter febrifuge. It remains widespread and is not considered threatened across its broad montane range.
Author: (D.Don) C.B.Clarke · Sources: POWO (Kew), GBIF, Flora of Nepal, Flora of Bhutan Vol. 2, Flora of Pakistan, A Revision of the Genus Swertia (Gentianaceae) in Asia