Wall.
Description
Primula petiolaris Wall. is a small, cushion- or mat-forming primrose of the Himalaya, distributed through Nepal, northern India, Bhutan and south-west China. It is a plant of cool, moist, shaded sites in the upper-temperate to alpine zone, growing on humus-rich banks, in rock crevices, beside streams and on mossy ledges, typically around 3000 to 4000 m. The recorded gatherings from below the Rupien La in Nepal at 3050 m and from Meggu Kichatti in Garhwal at 3100 m, the latter flowering in June soon after snowmelt, illustrate its early-season flowering in damp, semi-shaded high-mountain habitats where it forms low rosettes among rocks and moss.
The plant is a low, tufted perennial forming dense rosettes of obovate to spathulate leaves that taper gradually into a winged petiole (the basis of the epithet petiolaris), with finely toothed margins and a somewhat fleshy texture. The flowers are borne singly or in small clusters nestled within or just above the foliage on very short scapes, so that the plant appears almost stemless at flowering. Each flower has a tubular calyx and a salver-shaped corolla, rose-pink to purple with a contrasting white or yellowish eye ringing the throat. As in many primulas the species is heterostylous, with pin and thrum flower forms, and sets a small capsule releasing numerous fine seeds.
Primula petiolaris belongs to the large Himalayan radiation of section Petiolares, an intricate group of early-flowering, rosette-forming primroses whose species delimitation has long challenged taxonomists. Its precocious flowering, often as snow recedes, points to early-emerging insects as pollinators. Choice plants of this section are prized by alpine-garden growers, but P. petiolaris remains widespread and is not regarded as threatened, though its specialised montane microhabitats are sensitive to disturbance and climatic change.
Author: Wall. · Sources: POWO (Kew), GBIF, Flora of China (Primulaceae), Annotated Checklist of the Flowering Plants of Nepal, Flora of Bhutan, The Genus Primula (Richards)