Harry Sm.
Description
Saxifraga poluniniana is a cushion-forming alpine perennial of the western and central Himalaya, known from Nepal and India, with GBIF recording 30 occurrences. It occupies rock crevices, cliff faces, stable scree and moss-bound boulders in the upper subalpine to alpine zone. The photographed plant comes from south of Rara Lake in West Nepal at about 3800 m, flowering in June, a region of granitic outcrops and high-rainfall slopes where compact saxifrages thrive on shaded, moist rock.
The species forms dense, low cushions of small, crowded rosettes. The leaves are narrowly spathulate to linear-oblong, often hardened and lime-encrusted in the manner of section Porphyrion relatives, packed tightly to conserve moisture and resist wind exposure. The flowering shoots are short and usually carry a single, relatively large flower with five spreading petals, white to pale pink, ten stamens and a half-inferior ovary; the fruit is a small two-beaked capsule.
The taxon is accepted and was described by Harry Smith, a leading twentieth-century monographer of Sino-Himalayan Saxifraga, the epithet honouring the botanist Oleg Polunin, a noted collector in Nepal. As a narrow-range orophyte restricted to specialised rock habitats it is of considerable biogeographic interest; cushion saxifrages of this kind are valued in alpine horticulture and serve as indicators of intact high-altitude rock-ledge communities. Its limited known range warrants attention to its long-term conservation.
Author: Harry Sm. · Sources: POWO (Kew), GBIF, Flora of Nepal, Harry Smith's revisions of Asiatic Saxifraga, Polunin & Stainton's Flowers of the Himalaya