A shrub 2 to 5 ft high in the wild; young stems usually more or less covered with bristly hairs. Leaves short-stalked or almost sessile, oblong or oblong-elliptic or oblong-obovate, 11⁄4 to 3 in. long, 3⁄4 to 1 in. wide, rounded and mucronate at the apex, rounded or broad-cuneate at the base, of leathery texture, almost glabrous above, undersides papillose, glabrous on mature leaves except for a few floccose hairs. Flowers in terminal clusters of four to six, opening in April or May. Calyx variable in size, sometimes rim-like, sometimes 3⁄8 in. long, coloured like the corolla, which is in some shade of red, fleshy, tubular-campanulate, 11⁄4 to 11⁄2 in. long, five-lobed. Ovary tomentose and glandular. (s. Neriiflorum ss. Sanguineum)
Like other members of the confusing R. sanguineum complex, R. temenium is a native mainly of the Salween-Kiuchiang and Salween-Mekong divides in the Tibetan region of Tsarong and bordering parts of Yunnan. It resembles R. aperantum in the glabrous and papillose undersurface of the leaves, but that species is nearly always of dwarf habit, the stems are not bristly, and the leaf-bud scales are persistent (deciduous in R. temenium). It comes from alpine elevations and makes a compact, hardy bush.
subsp. albipetalum Cowan – Flowers white. Introduced by Rock.
subsp. chrysanthemum Cowan – Flowers yellow. Ovary tomentose, but not glandular. Introduced by Rock. The clone 'Cruachan', raised from his no. 22272, received an Award of Merit on April 22, 1958, and a First Class Certificate in 1964, on both occasions when shown by Mrs K. L. Kenneth, Tich-an- Rudha, Ardrishaig; the flowers are sulphur-yellow. The original plant has since died. The subsp. gilvum Cowan is similar, but the ovary is glandular.
subsp. glaphyrum (Balf. f. & Forr.) Cowan R. glaphyrum Balf. f. & Forr. – Flowers cream or rose or a blend of the two. Ovary eglandular. Introduced by Forrest.
subsp. pothinum (Balf. f. & Forr.) Cowan R. pothinum Balf. f & Forr. – Like typical R. temenium, but with the ovary devoid of glands. Introduced by Forrest.
From the Supplement (Vol. V)
A simplified treatment of this species is provided in Rev. 2, pp. 404-5.
var. temenium R. pothinum Balf.f. & Forr. R. temenium subsp. pothinum (Balf.f. & Forr.) Cowan – Young shoots and pedicels bristly. Flowers carmine to crimson.
var. dealbatum (Cowan) Chamberlain, including R.t. subsp. glaphyrum Cowan – Flowers white to deep pink. Inflorescence lax. Bristles weakly developed.
var. gilvum (Cowan) Chamberlain, including R.t. subsp. chrysanthemum Cowan – Flowers yellow. Otherwise as in var. temenium.