Usually an epiphytic shrub, to 2 m; young growth with a dense indumentum of stiff twisted and matted hairs. Leaves 7.5-11.5 x 3.8-5.5 cm, narrowly ovate to ovate-oblong, apex acuminate, upper surface with dense matted stiff hairs overlying the midrib, lower surface with dark brown close, more or less equal scales that are set in pits and have upturned rims. Pedicels stout, to 15 mm, indumentum as for young growth. Flowers (3-)4-6(-10) per inflorescence; calyx lobes (7-)10-15 mm; corolla dull to bright yellow, sometimes spotted, campanulate, tube c.15 mm, lobes 10-12mm; stamens 10; ovary scaly, tapering into the declinate style. Flowering April-May.
This tender species is rare in cultivation Royal Horticultural Society (1997)
Distribution China S Tibet India Arunachal Pradesh
Habitat 1,800-2,450 m
RHS Hardiness Rating H2
Conservation status Near threatened (NT)
Taxonomic note (incl. R. mishmiense Hutch. & Kingdon-Ward) Royal Horticultural Society (1997)
An evergreen shrub 6 to 8 ft, sometimes 10 ft high, of loose habit; young shoots at first very hairy. Leaves leathery, oval-ovate, slenderly pointed; 31⁄2 to 5 in. long, 11⁄4 to 21⁄2 in. wide, dark green and ultimately glabrous above, but sprinkled with long hairs when young and hairy on the margins; scaly beneath; stalk about 1⁄4 in. long and clothed with shaggy hairs like the young shoot. Flowers rich yellow, seven to ten of them closely packed in a terminal cluster, opening in April and May. Calyx membranous, deeply five-lobed, the lobes broadly ovate, rounded, 1⁄4 in. long, sparsely hairy on the margins. Corolla 1 to 11⁄2 in. wide, bell-shaped at the base, separating into five broad, rounded lobes; scaly outside. Stamens ten, their stout stalks very hairy at the lower half; anthers standing just clear of the corolla-tube. Ovary 1⁄4 in. long, conical, closely covered with scales, surmounted by a glabrous, thick, much decurved style. Bot. Mag., t. 7149. (s. and ss. Boothii)
A little-known species, discovered by Thomas Booth on December 16, 1849, in an outer range of the Assam Himalaya, north-west of Tezpur, growing epiphytically on oaks at about 5,000 ft, and introduced by him. R. camelliiflorum and R. edgeworthii also grew as epiphytes in the same locality. He wrote in his journal: ‘found many on old decayed and blown down trees on the ground, destitute of seeds or flower buds. With great difficulty and delay I obtained seed of these species by climbing such trees as were practicable, and cutting off the boughs on which they were located’ (Gard. Chron., 1862, p. 406). It was found again in the same area but farther north by Kingdon Ward in 1935 (fruit) and 1938 (flower), between Tembang and Lagam (Assam Adventure, p. 266; Gard. Chron., Vol. 102 (1937), p. 143).
R. boothii is not hardy near London, but has been successfully grown in the open air in the south-west. It is however very rare in cultivation. Its flowers and trusses are small, but attractive in the uncommon colour.
[R. mishmiense]. – Included in R. boothii.