W.W.Sm.
Description
Saxifraga caveana W.W.Sm. is a high-alpine cushion saxifrage endemic to the Sino-Himalayan region, with GBIF records (c. 48 occurrences) from Bhutan, Nepal, China and India. It occupies the upper alpine zone, growing among rocks, on stony slopes, screes and in crevices of moist cliffs, typically between about 4,000 and 5,000 m. The photographed plant from the Kagmara-La in west Nepal at roughly 4,200 m, flowering in July, illustrates its habitat well: a cold, exposed, snow-fed pass environment where the short summer monsoon period coincides with peak flowering.
The species is a small perennial herb forming low tufts or loose cushions from a branched caudex. The leaves are mostly basal, rosulate, small, oblong to spathulate, often somewhat fleshy and ciliate at the margins, and may bear lime-secreting hydathode pores characteristic of many saxifrages. Flowering stems are short, glandular-pubescent, and bear one to few flowers. The flowers are typically pentamerous, with five free sepals and five obovate petals that are pale yellow to whitish, sometimes finely spotted; the ovary is more or less superior with two carpels developing into a capsule that dehisces apically to release numerous minute seeds.
Within the large and intricate genus Saxifraga, S. caveana belongs to the assemblage of Himalayan alpine species whose taxonomy has been clarified mainly through the work on section Ciliatae and related groups. As a narrow-range, high-elevation specialist, it is potentially vulnerable to climate-driven upward shifts of the alpine zone, though its remote habitat affords protection from direct human disturbance.
Author: W.W.Sm. · Sources: POWO (Kew), Flora of China Vol. 8, Flora of Nepal, Flora of Bhutan Vol. 1, GBIF, Pan Jintang & Gornall: Saxifragaceae revisions