Maxim.
Description
Androsace tapete Maxim. is a cushion-forming rock-jasmine of the high Himalaya and Tibetan plateau, documented by some 579 records from China, Nepal, India and Bhutan. It is a true subnival specialist, growing on exposed gravelly and rocky slopes, screes, moraines and stony alpine flats, typically between about 4000 and 5500 m. The plant photographed at the Kagmara-La in West Nepal at 4550 m in July epitomises its habitat: a wind-blasted, intensely irradiated, frost-prone pass where it forms tight hemispherical cushions hugging the substrate.
The species is a compact, perennial, evergreen cushion plant built from densely packed columnar shoots, each terminating in a small rosette of imbricate, oblong-spathulate leaves clothed in long white hairs that trap warmth and reduce desiccation. Dead leaves are retained internally, packing the cushion into a firm dome (the epithet "tapete" meaning carpet). The flowers are solitary, sessile or nearly so among the rosette leaves, with a small gamopetalous corolla, the five lobes white to pink with a yellow or reddish eye, borne over a short tube. The fruit is a small few-seeded capsule largely enclosed within the persistent calyx.
Androsace tapete belongs to section Aretia (the aretioid cushion androsaces), a group whose extreme cushion architecture represents convergent adaptation to the cold, dry, high-radiation conditions of the world's highest vegetated terrain. The cushion modifies its own microclimate, ameliorating temperature and moisture and often facilitating other alpine species. Restricted to remote high-altitude habitats and slow-growing, such cushion plants are sensitive to climate warming and trampling, although A. tapete remains widespread and is not formally assessed.
Author: Maxim. · Sources: POWO (Kew), GBIF, Flora of China, Flora of Nepal, monograph of Androsace (sect. Aretia), Smith & Lowe's cushion Androsace studies