H. Hara
Description
Stellaria congestiflora is a high-alpine chickweed of the Himalaya, recorded from Nepal, China, Bhutan and India, a restricted and infrequently collected distribution reflected in its small number of georeferenced records. It grows in alpine meadows, on stony slopes, screes and the gravelly margins of streams and snowbeds at high elevations, generally well above 4000 m. The plant photographed at Churta-Khola in West Nepal at 4230 m in June is a characteristic occurrence in the cold, open alpine zone, flowering soon after snowmelt at the upper limit of vascular plant growth.
It is a small, tufted or mat-forming perennial herb arising from a slender, branched rootstock. The stems are short, slender and often densely clothed, bearing opposite, sessile, narrowly lanceolate to linear leaves. As the epithet indicates, the small white flowers are aggregated into congested, head-like terminal clusters subtended by leafy bracts, rather than borne in the open, spreading cymes typical of many relatives. Each flower has five sepals and five deeply bifid white petals, ten stamens and a superior ovary bearing three styles; the fruit is a capsule dehiscing by valves to release several small seeds.
Stellaria is a large, cosmopolitan genus of the Caryophyllaceae distinguished by the deeply two-cleft petals, and the dense, congested inflorescence of S. congestiflora, described by H.Hara, separates it from the looser-flowered Himalayan species. Its narrow, high-elevation range makes it potentially sensitive to alpine climate change and habitat shifts, though its remote habitat limits direct human pressure. As a cushion-like alpine herb it contributes to the sparse but specialised flora of the upper screes and snowbed margins.
Author: H. Hara · Sources: POWO (Kew), GBIF, Flora of China, Annotated Checklist of the Flowering Plants of Nepal, Hara's Flora of Eastern Himalaya, monographic studies of Himalayan Stellaria (Caryophyllaceae)