Craib
Description
Primula irregularis Craib is a Himalayan primrose of restricted range, recorded in GBIF (about 45 occurrences) from Nepal, northern India and Bhutan. It is a plant of cool, humid temperate to subalpine habitats, growing on mossy banks, shaded forest floors, damp rock crevices and the margins of rhododendron and oak forest, broadly between about 2400 and 3500 m. The collections noted from Doch-La in Bhutan at 3000 m in April and from Suketar in eastern Nepal at 2400 m in March show it flowering very early, as winter snow recedes, in the moist, cloud-influenced mid-montane forest belt that characterises its niche.
It is a small farinose perennial forming a basal rosette that resumes growth early from a resting bud. The leaves are obovate to oblong, with a crenate-dentate, somewhat irregularly toothed margin tapering into a winged petiole, the undersurface frequently dusted with whitish or yellowish farina. The flowers open close to the rosette on a very short scape, solitary or in a few-flowered umbel. The corolla is salverform, with a slender tube and a spreading limb of obcordate, deeply emarginate lobes, pale lilac to violet with a contrasting paler or yellow eye. As in other primroses the species is heterostylous, and the small capsule contains numerous minute seeds.
Primula irregularis belongs to section Petiolares, the large Sino-Himalayan assemblage of early-flowering, farinose primulas whose species are notoriously difficult to delimit and which has been the subject of repeated revision. Heterostyly enforces outcrossing between long- and short-styled morphs. With its narrow range and dependence on perennially cool, moist microhabitats, the species is regionally restricted and likely sensitive to warming and habitat disturbance, characteristics shared by many of the high-altitude Petiolares primulas of the eastern Himalaya.
Author: Craib · Sources: POWO (Kew), GBIF, Annotated Checklist of the Flowering Plants of Nepal, Flora of Bhutan, Richards' monograph Primula, Flowers of the Himalaya