Bhutan: Chukha,Thimphu, Punakha, Trongsa, Bumthang,Mongar, Upper Kuru Chu and Upper Kulong Chu districts. Amongst Rhododendrons and bamboos in Fir and Hemlock forests, 2890-3450m. April- May.

Endemic to Bhutan. Formerly confused with R.hodgsonii and often misidentified as a hybrid between R.hodgsonii * R.falconeri.It differs from both those species in its rounded bud-scales, very prominent laeral veins, white or silvery indumentum without cup-shaped hairs, pink flowers and presence of necter-pouches.

Morphology

Similar to R. grande but young shoots often closely white floccose, leavesbroadly elliptic to almost obovate, 20-30x10-16cm, apex rounded, minutely mucronate, base cuneate or rounded, silvery white beneath with thicker(sometimes loosely floccose) indumentum, lateral veins stout, 12-15pairs; corolla smaller, 3-4.7cm, pink; ovary densely glandular, sometimes also thinly tomentose; capsules narrower, 3.5-4x0.9-1cm, curved.

Evergren shrubs or trees, often aromatic; indumentum of simple or compound hairs or peltate scales. Leaves alternate or clusterd at branch ends, coriaceous, entire. Flowers in terminal condensed racemes, rarely solitary, weakly zygomorphic. Calyx 5(-8)-lobed, often reduced to a shallow cup. Corolla campanulate, funnel-shaped or salver-shaped, rarely cylindric, with 5-10 long or short lobes. Stamens (5-)10(-18). Ovary5-20-celled; stigma capitate. Capsule 4-20-valved.

Taxonomy. Rhododendron taxonomy has been the subject of considerable controversy due to different approaches taken by specialists over the past century. Much taxonomy was sometimes described as new species with little attempt to relate them to the natural varietion in wild populations. Hybridzation in the wild and in cultivation has, until recently, been underestimated. Recent revisions by Chamberlian(180) and Cullan(183) have attempted to give specific names only to those which formed discrete, recognisable entities in the wild. Thus many 'old'names have been relegated to synonomy or to subspecific or varietal rank. For example, some were considered to represent clones or hybrids with no clear identity in the wild, as in those species now treated as synonymes of R.maddenii.

This system has been broadly follewed here, with minor amendments such as the recognition of R.flinckii and R. aeruginosum. Many taxonomic problems remain in Bhutanese species however, which require detailed study in the wild, such as R.grande, R. thomsonii, R.campanulatum, R.maddenii and their relatives.

A number of Rhododendron species not treated here, have been reported from Bhutan(80), such as R.boothii Nuttall, R.formosum wall., R.hookeri Nuttal and R.nuttallii Booth. The record of R.formosum is probably based on a mis-labelled Griffith specimen from 'Bootan', but were in fact collected in Arunachal Pradesh. Some of these species could, however, be discovered in eastern Bhutan in future.

The genus Rhododendron is of potential economic importance in Bhutan, because most of the species are gtreatly prized in horticulture in Europe and N America, and although a number are already widely grown in those continents, there is the tendency for rhododendrons of known in those continents, there is considerable demand for it of known wild origin. One reason for this is the tendency for hybridization to occur in cultivation, so that wild seed is preferable to replenish stocks periodically. Species widely cultivated include R.anthopogan, R.arboreum, R.barbatum, R.campulatum, R.cinnabarinum, R.edgeworthii, R.falconeri, R.grande, R..hodgsonii, R. maddenii, R.lepidotum and R.thomsonii. However, many others, such R. argipeplum, R.baileyi, R.bhutanense, R.ciliatum, R.flinckii, R.kesangiae, R.keysii, R.leptocarpum, R.neriiflorum, R.niveum, R.papillatum,Rpogonophyllum and R.succothii are much less widely grown or even unknown in cultivation from Bhutanese origin. A very good treatment of the genus and its horticultural importance, as well as all the Sino-Himalayan species and their cultivation is given in t