H. Ohba
Description
Sedum amabile is a high-alpine succulent of the Eastern Himalaya, recorded principally from Bhutan and the adjacent mountains of Sikkim and southern Tibet (China). GBIF currently holds no georeferenced occurrences and no associated country list for this name, reflecting both its rarity and the unsettled status discussed below. It is a plant of the high alpine zone above about 4000 m, growing among rocks, on stony slopes, moraine and in crevices, as documented along the Ludlow-Sherriff Trail at Warrtlang-La in Bhutan at 4450 m. Like other high-elevation stonecrops it is adapted to a short, cool growing season, flowering in early summer (June) shortly after snowmelt.
It is a small, glabrous, succulent perennial herb forming low tufts from a short rootstock, with fleshy stems bearing crowded, fleshy leaves that are entire, sessile and oblong to obovate. The flowers are borne in a compact, terminal, cymose to corymbose inflorescence; they are typically 5-merous, with free or nearly free petals that in this species are an attractive bright reddish-pink (the epithet "amabile" meaning lovely or pleasing), and twice as many stamens as petals. The carpels are erect and free, maturing into a star-like cluster of small follicles that split along the ventral suture to release numerous minute seeds.
Though catalogued under the genus Sedum, GBIF treats this name as a synonym, with the accepted name given as Sedum amabile; the basionym by H. Ohba and the WordPress link (referencing Rhodiola amabilis) indicate the long-standing taxonomic movement of high-Himalayan succulents between Sedum and the segregate genus Rhodiola, distinguished chiefly by the latter's perennial scaly caudex and frequently dioecious flowers. Such nomenclatural instability is typical of the Sino-Himalayan Crassulaceae. Given its very restricted, high-altitude range and the paucity of records, the species is potentially of conservation concern, although it has not been formally assessed.
Author: H. Ohba · Sources: POWO (Kew), GBIF, Flora of Bhutan, Flora of China, Ohba's monograph of Himalayan Crassulaceae (Sedum and Rhodiola)