(C.B.Clarke) Su.Datta & B.K.Sinha
Description
Didymocarpus punduanus var. pulchrus is an eastern Himalayan member of the Gesneriaceae, known from the moist montane forests of Bhutan and the adjacent Himalaya. No georeferenced GBIF occurrences are currently available for this infraspecific taxon, reflecting its narrow circumscription and limited collecting. Like its relatives it is a saxicolous to terrestrial herb of shaded, humid habitats, growing on mossy rock faces, cliff ledges, ravine banks and damp forest slopes in the temperate zone. The photographed plant from Wangdi (Wangdue Phodrang) in Bhutan, at 2800 m and flowering in September, indicates a preference for cool, sheltered mid-montane sites with high humidity.
The plant is a small perennial herb, frequently with a short rhizomatous rootstock and opposite, ovate to elliptic leaves that are crenate-serrate and softly pubescent, with the bullate, sunken venation typical of the genus. The flowers are borne in axillary, pedunculate cymes; each has a tubular, somewhat two-lipped corolla, often purple to violet or pinkish, with a slightly oblique limb of five rounded lobes. There are two fertile stamens (the reduction characteristic of Didymocarpus) with cohering anthers, plus staminodes. The gynoecium develops into the elongate, narrowly cylindrical, septicidal capsule diagnostic of the genus, splitting to release numerous minute seeds.
The family placement given here as "Didymocarpinae" refers to the subtribe Didymocarpinae of the Gesneriaceae (tribe Trichosporeae), within which Didymocarpus is a large Asian genus centred on the Himalaya and Southeast Asia. This taxon, based on a Clarke epithet and recombined by Datta and Sinha, is treated at varietal rank; the source links to a Didymocarpus pulcher page, reflecting nomenclatural movement around the name. As a narrowly distributed forest endemic it is potentially of conservation interest but remains formally unassessed.
Author: (C.B.Clarke) Su.Datta & B.K.Sinha · Sources: POWO (Kew), GBIF, Flora of Bhutan, The Gesneriaceae of the Eastern Himalaya, A revision of Didymocarpus (Gesneriaceae)