Shrub or small tree, 2–8 m; young shoots densely glandular-setose. Leaves herbaceous, 11.5–30 × 3.3–8 cm, obovate to elliptic, apex cuspidate, upper surface smooth, lower surface covered with glandular setae, especially on veins and midrib. Flowers 10–14 in a truss; calyx 5–10 mm; corolla rose-pink to scarlet, with purple flecks and usually also a purple basal blotch, campanulate, 30–50 mm; ovary densely stalked-glandular. Flowering April-May. Royal Horticultural Society (1997)
Distribution China S Tibet, NW Yunnan
Habitat 2,100–4,000 m
RHS Hardiness Rating H4
Conservation status Least concern (LC)
Taxonomic note R. glischrum is allied to R. habrotrichum, from which it may be distinguished by the leaf shape, and to R. glischroides, from which it differs in its smooth upper leaf surface. Royal Horticultural Society (1997)
An evergreen tree up to 25 ft high in nature, mostly seen in cultivation as a shrub of stiff, rather gaunt habit; young shoots, leaf-stalks, and flower-stalks all glandular-bristly. Leaves narrowly oblong, often inclined to oblanceolate, rather abruptly narrowed at the apex to a slender point; tapered, rounded, or slightly heart-shaped at the base, 6 to 12 in. long, 11⁄2 to 3 in. wide, dark green or yellowish green and eventually glabrous above, pale green beneath and more or less furnished all over with bristly down, but especially on the midrib. Flowers borne during May in trusses 5 or 6 in. across, of up to fifteen or more, on stalks up to 11⁄2 in. long. Calyx deeply five-lobed, the lobes 3⁄8 in. long, oblong, blunt, bristly. Corolla bell-shaped, five-lobed, 2 in. wide, varying in colour from a dull magenta-pink to a purplish rose with a dark blotch at the base. Stamens ten, 1 to 11⁄4 in. long, glandular-downy towards the base. Ovary and base of style clothed with white bristles. Bot. Mag., t. 9035. (s. Barbatum ss. Glischrum)
R. glischrum was discovered by Forrest on the Kari pass, Mekong-Salween divide in 1914, and was introduced from there. Subsequently it was collected over a wide area from here westward to the eastern end of the Himalaya. The type specimens bore only withered flowers, but Forrest noted the colour of his later findings as ‘plum-purple’, ‘clear rose’, or ‘white flushed rose’. In cultivation, many of the plants raised from the wild seeds had flowers of an unpleasant magenta shade, but in the best forms, which may be the minority, they are clear red in the bud, opening rosy pink or rosy lilac. R. glischrum is hardy in woodland near London, but is probably best suited in the rainier parts of the country. It is, in any case, rarely seen outside collections.
The var. adenosum has been raised to species rank; see below. The species mentioned under R. glischrum on page 673 are disposed of as follows in the Edinburgh revision:
subsp. glischroides (Tagg & Forr.) Chamberlain R. glischroides Tagg & Forr.
subsp. rude (Tagg & Forr.) Chamberlain R. rude Tagg & Forr.
R. vesiculiferum – Accepted as a distinct species.
R. adenosum (Cowan & Davidian) Davidian R. glischrum var. adenosum Cowan & Davidian; R. kuluense Chamberlain – Although allied to R. glischrum, this is distinct from it in foliage and occupies a separate area to the east of it (Rev. 2, p. 284).
Leaves glabrous above at maturity though sometimes with a few setae above midrib at base.
Distribution NE Burma, China (S Tibet, NW Yunnan).
R. rude Tagg & Forrest
Leaves with persistent setae on upper surface, even when mature.
Distribution China (NW Yunnan).
Awards AM 1968 (Crown Estate Commissioners, Windsor) to a clone ‘High Flier’, as R. rude; flowers red-purple in bud, opening white, flushed red-purple up centre of lobes. AM 1969 (A.C. & J.F.A. Gibson, Glenarn, Dunbartonshire) to a clone ‘Frank Kingdon-Ward’, as R. rude; flowers pinkish purple, spotted.