(R.Knuth) Govaerts
Description
Androsace jacquemontii var. robusta is a high-alpine cushion plant of the western and central Himalaya and the Tibetan borderlands, recorded from China, India, Nepal and Pakistan among its roughly 212 documented occurrences. It is a denizen of the upper alpine zone, growing on stony slopes, fine moraine, gravelly flats and rock crevices where drainage is sharp and exposure severe. The photographed population at the Kagmara-La in West Nepal, at about 4800 m and flowering in July, is characteristic of its elevational ceiling, where the brief snow-free season concentrates flowering into the early summer weeks following snowmelt.
The plant forms dense, compact cushions or low mats built from numerous crowded rosettes of small, imbricate, linear to oblanceolate leaves, often somewhat fleshy and ciliate at the margins, an adaptation conserving heat and moisture in the windswept environment. From the rosettes arise short scapes bearing solitary flowers or small few-flowered umbels; each flower has a five-lobed campanulate calyx and a salverform corolla with a constricted throat marked by a yellow or pinkish eye, the spreading lobes usually pink to lilac or white. The fruit is a small, few-seeded capsule dehiscing by valves at the apex, the var. robusta distinguished by its more vigorous, larger habit relative to typical A. jacquemontii.
Androsace is the classic genus of Himalayan rock-jasmines within Primulaceae, and the cushion-forming alpines exemplify convergent adaptation to cold, high-radiation environments shared with Saxifraga and Arenaria. The recombination of this taxon, originally a Knuth name, by Govaerts reflects ongoing nomenclatural refinement of the infraspecific entities. Cushion plants of this kind are long-lived, slow-growing and act as nurse plants facilitating other seedlings; while not individually threatened given their remote habitat, they are recognised as sensitive sentinels of warming-driven change in high-mountain vegetation.
Author: (R.Knuth) Govaerts · Sources: POWO (Kew), GBIF, Flora of Pakistan, Flora of China, Annotated Checklist of the Flowering Plants of Nepal, Smith and Lowe's monograph of Androsace (Primulaceae)