Hook. f.
Description
An evergreen rhododendron of the eastern Himalaya, native to China, Bhutan, Nepal and India, with about 353 GBIF occurrences (extra-range entries reflect cultivation in botanic gardens). It is a shrub to small tree of the upper subalpine and lower alpine zone, forming part of rhododendron-fir and dwarf rhododendron scrub, on cool, moist, humus-rich slopes generally between about 3300 and 4300 m. The depicted plants were photographed in May on the Bhutanese passes of Chele-La at around 3900 m and Shele-La at about 3800 m, exposed high-elevation habitats where it flowers as the snow recedes.
The species forms a rounded shrub with smooth, peeling bark and stout branchlets. The leaves are coriaceous, elliptic to oblong-elliptic, dark green and glabrous above, and beneath bear a distinctive thin, patchy, fawn to brownish indumentum of dendroid hairs that often wears away to leave scattered remnants. The flowers are borne in compact terminal trusses; each has a campanulate corolla of pale lilac to rose-pink, often with crimson basal blotches and spotting, the limb shallowly seven- to eight-lobed, with numerous stamens and a glabrous ovary topped by a slender style. The fruit is a curved, woody, septicidal capsule releasing many small winged seeds.
Though GBIF flags the name as a synonym, R. wallichii is widely accepted at species rank and placed in subsection Campanulata, allied to R. campanulatum, from which it is separated by its thinner, more fugacious leaf indumentum. Ecologically it is a major component of high Himalayan rhododendron heath, providing spring nectar and structural cover. Locally abundant within its range, it faces no immediate threat but is sensitive to grazing pressure, fire and the warming of its narrow alpine belt.
Author: Hook. f. · Sources: POWO (Kew), GBIF, Flora of Bhutan, Flora of China, Royal Botanic Garden Edinburgh revision of Rhododendron