W.W. Sm.
Description
Primula whitei W.W.Sm. is an eastern Himalayan primrose of comparatively narrow range; GBIF lists about 74 occurrences from Bhutan, neighbouring India, southern China and Myanmar, with records extending into eastern Nepal. It grows in cool, moist habitats of the upper temperate and subalpine zones, on mossy banks, damp rock ledges, shady cliffs and the margins of forest and scrub, broadly between about 3000 and 4000 m. The plants photographed at Pele-La in Bhutan at 3000 m in April flower very early in the season, as snow recedes, on a high pass typical of the humid, cloud-bathed habitats this species requires.
It is a small, farinose perennial herb forming a compact rosette that overwinters as a resting bud. The leaves are obovate to spathulate, with a crenate to dentate margin tapering to a winged petiole, and the undersurface is often dusted with white or yellowish farina. The flowers are borne singly or in a small umbel on a short scape that elongates only slightly after anthesis, so the blooms nestle close to the foliage. The corolla is salverform with a slender tube and spreading limb of obcordate lobes, violet-blue to lilac with a paler or yellowish eye. The species is heterostylous, and the fruit is a small capsule releasing numerous minute seeds.
Primula whitei belongs to section Petiolares, a Sino-Himalayan group of early-flowering, often farinose primulas centred on the eastern Himalaya whose species delimitation has long challenged taxonomists; it has at times been associated with the Primula bhutanica complex. The genus is classically heterostylous, promoting outcrossing between pin and thrum morphs. With its limited range and reliance on cool, perennially humid microhabitats, the species is regionally restricted and potentially sensitive to warming and to desiccation of the high-altitude niches on which Petiolares primulas depend.
Author: W.W. Sm. · Sources: POWO (Kew), GBIF, Flora of Bhutan, Flora of China, Richards' monograph Primula, Annotated Checklist of the Flowering Plants of Nepal