Hook.f. & Thomson
Description
Chrysosplenium tenellum is a diminutive, high-alpine member of its genus restricted to the central and eastern Himalaya, with a sparse GBIF record (32 occurrences) from India, Nepal, Bhutan and China that reflects both its narrow range and its inconspicuous habit. It grows in cold, wet places near the upper limit of vegetation: on dripping rocks, beside snowmelt rills, in mossy seepages and on shaded humus among boulders, generally between about 3500 and 4500 m. The collections illustrated from the Chele La in Bhutan, at 4300 m in May and 3900 m in April, document its very early flowering immediately following snowmelt at these elevations.
The plant is a delicate, slender perennial herb, the epithet tenellum aptly describing its tenuous form. It produces fine, creeping and rooting stems that form small loose patches, with thin filiform stolons. The leaves are small, alternate or the lower opposite, petiolate and reniform to orbicular with a few shallow crenations. As in all Chrysosplenium the flowers lack petals; the tiny terminal cyme is subtended by small yellowish-green leafy bracts that provide the floral display. Each flower has four greenish sepals, few stamens and a half-inferior ovary maturing into a small two-lobed, divaricately beaked capsule that opens to release minute seeds dispersed by splashing water.
Within the moisture-dependent genus Chrysosplenium, C. tenellum represents the alpine extreme, a slight plant of fragile, ephemerally wet microhabitats at the margins of permanent snow. Its small flowers are visited by the few high-altitude flies active early in the season. Owing to its restricted distribution, specialised hydrological niche and low number of documented occurrences, the species is potentially vulnerable to warming-driven shifts in snowmelt regimes, although it has not been formally assessed.
Author: Hook.f. & Thomson · Sources: POWO (Kew), GBIF, Flora of China, Flora of Bhutan, Annotated Checklist of the Flowering Plants of Nepal, Monograph of Chrysosplenium (Hara)