C.B.Clarke
Description
Strobilanthes lachenensis C.B.Clarke is a shrubby herb of the Acanthaceae endemic to the eastern Himalaya and adjacent ranges, recorded from China, Nepal, India and Bhutan, with about 125 GBIF occurrences. It grows in the understorey and along the margins of temperate broad-leaved and mixed forest, on shaded slopes, banks and forest clearings, mainly between about 1800 and 2800 m. It was documented in Bhutan at Semkota near 2000 m in October, an autumn flowering that accords with the often gregarious, plietesial flowering behaviour characteristic of many Himalayan Strobilanthes, in which populations bloom synchronously after several years of vegetative growth.
It is an erect, branched perennial or subshrub with quadrangular stems that are swollen at the nodes. The leaves are opposite and conspicuously anisophyllous, the pair unequal, elliptic to lanceolate, acuminate, with crenate-serrate margins and cystoliths visible as fine streaks on the surface. The flowers are borne in spike-like or capitate inflorescences subtended by bracts; the bilabiate, funnel-shaped corolla is blue to pale violet, curved and slightly inflated at the throat, enclosing four didynamous stamens. The fruit is an elongate, two-valved capsule that dehisces explosively, ejecting a few flattened seeds borne on hooked retinacula.
Strobilanthes is a large and taxonomically complex genus centred on tropical and subtropical Asia, and the Sino-Himalayan species such as S. lachenensis form part of an intricate, much-revised assemblage. Its mass-flowering, bee-pollinated reproductive strategy and the type locality at Lachen in Sikkim, from which the epithet derives, anchor it in the eastern Himalayan flora. The species is forest-dependent and locally distributed, making it potentially sensitive to habitat disturbance, though it is not formally assessed.
Author: C.B.Clarke · Sources: POWO (Kew), GBIF, Flora of China, Flora of Bhutan, Flora of British India, Strobilanthes monograph (Wood; Carine & Scotland revision of Strobilanthes)