122a. Rhododendron cinnabarinum subsp. cinnabarinum
朱砂杜鹃(原亚种) zhu sha du juan (yuan ya zhong)
Leaf blade oblong-elliptic to oblong-lanceolate, or ovate to elliptic. Corolla tubular to narrowly campanulate, yellow to cinnabar red (sometimes 2-colored) or deep plum crimson; lobes without scales abaxially.
Forests, open woodlands, among shrubs, hillsides; 1900–4000 m. S Xizang [Bhutan, NE India, Nepal, Sikkim].
Two varieties have been recorded from China: var. cinnabarinum and var. roylei (J. D. Hooker) Hutchinson in J. B. Stevenson, Sp. Rhodod. 222. 1930; R. roylei J. D. Hooker, Rhododendr. Sikkim-Himalaya 1: t. 7. 1849 [“roylii”]). The latter taxon is distinguished by its deep plum crimson corolla. The populations of var. cinnabarinum in W Bengal, India, exhibit a range of corolla colors, from yellow or orange, through 2-colored forms, to deep cinnabar.
Rhododendron cinnabarinum var. purpurellum Cowan (Notes Roy. Bot. Gard. Edinburgh 21: 147. 1951) has also been recorded from China and was accepted by Yang in FRPS (57(1): 136. 1999). However, Cullen (Notes Roy. Bot. Gard. Edinburgh 39: 124. 1980) treated it as a purple-flowered variant in the synonymy of R. cinnabarinum subsp. xanthocodon (R. xanthocodon in the present account).