A.J.Richards
Description
Primula tanneri subsp. nepalensis is a subalpine to alpine primula of the Himalaya; under the GBIF backbone the name is treated as a synonym, with Primula tanneri nepalensis given as the accepted name. The GBIF records, though few (around ten occurrences) and centred on Nepal, accompany a wider distribution of the species through the Central and Eastern Himalaya including Bhutan. It grows in moist alpine and subalpine habitats, among open Rhododendron scrub, damp turf and shaded rocky slopes near the treeline. The plant figured was recorded at Jule-Tso in Bhutan at about 3,900 m in June, flowering early in the growing season.
It is a glabrous perennial herb with a basal rosette of obovate to oblong-spathulate leaves, the margins toothed and the blade tapering to a winged petiole, often more or less efarinose. The flowering scape is erect and bears a terminal umbel of several flowers, each subtended by linear bracts. The corolla is deep purple to violet, somewhat funnelform, with a short tube and a spreading limb of five emarginate lobes, the throat marked by a paler or yellowish eye. As typical of the genus the species is heterostylous, producing distinct pin and thrum morphs, and the fruit is a many-seeded capsule.
Primula tanneri belongs to the petiolarid alliance of Himalayan primulas, and subsp. nepalensis represents the western, Nepalese-centred expression of this variable species, distinguished by leaf and farina characters from the typical eastern subspecies. The heterostylous breeding system promotes obligate outcrossing by insects. With a restricted range and few documented populations it is naturally local; while not formally evaluated, such narrowly distributed alpine taxa warrant monitoring against climatic shifts.
Author: A.J.Richards · Sources: POWO (Kew), GBIF, Flora of Bhutan, Annotated Checklist of the Flowering Plants of Nepal, Richards' Primula (monograph), Smith & Fletcher revision of Asiatic Primula