Hook. f.
Description
Rhododendron lanatum is an East Himalayan species restricted to the eastern Himalaya, ranging from Sikkim and adjacent northern India through Bhutan to south-eastern Xizang and Yunnan in China, with peripheral records in Nepal; its roughly 180 georeferenced occurrences (IN, BT, CN, NP) reflect a comparatively narrow distribution, supplemented by garden records in Britain and Sweden. It is a component of the subalpine Rhododendron-Abies forest and shrubberies, growing on humus-rich, acidic slopes and rocky moraine between about 3000 and 4300 m. The plants documented on the Bhutanese passes of Tumching-La and Tumcheng-La between 3400 and 3900 m, flowering from April into May, occupy exactly this cool, cloud-soaked subalpine zone.
It is an evergreen shrub or small tree to 3-4 m, conspicuous for the dense rusty to fawn woolly (lanate) indumentum that clothes the young shoots, leaf undersides and bud scales. The leaves are coriaceous, oblong-elliptic, glabrous and dark green above but covered beneath with a thick, two-layered tomentum of branched hairs. The bell-shaped (campanulate) flowers, pale to sulphur-yellow and often flecked with crimson at the base, are 3-4 cm long and grouped in dense terminal trusses of up to a dozen; the corolla bears five lobes, ten stamens and a glabrous ovary. The fruit is a curved, woody, septicidal capsule releasing numerous minute winged seeds.
Rhododendron lanatum belongs to subsection Lanata of subgenus Hymenanthes, a small group defined by their woolly indumentum and yellow campanulate flowers, allied to R. wightii. Its narrow eastern Himalayan range and dependence on intact subalpine forest make it locally vulnerable to grazing, fire and woodland degradation, though it remains frequent within Bhutan's protected highlands.
Author: Hook. f. · Sources: POWO (Kew), GBIF, Flora of Bhutan, Flora of China, Cox's The Larger Rhododendron Species, The Genus Rhododendron (Royal Botanic Garden Edinburgh)