黄铃杜鹃 huang ling du juan

Rhododendron cinnabarinum J. D. Hooker var. purpurellum Cowan; R. cinnabarinum subsp. xanthocodon (Hutchinson) Cullen; R. concatenans Hutchinson.

Erect shrubs or small trees, evergreen, 1.5–7.5 m tall. Petiole 8–15 mm, scaly; leaf blade leathery, elliptic or oblong-elliptic, 3–7.5 × 1.5–4.5 cm, less than 2.2 × as long as broad; base usually rounded; apex obtuse, mucronate; abaxial surface pale green, scales less than 1 × their own diameter apart, unequal, dark brown, brown or golden; adaxial surface olive green, shiny, scales dense. Inflorescence terminal, shortly racemose or nearly umbellate, 2–6(–8)-flowered. Pedicel ?usually 1.5–2.5 cm, sparsely scaly; calyx lobes 1–2 mm, shortly triangular or ovate, densely scaly abaxially and on margin; corolla tubular-campanulate, creamy yellow, 2.5–3.2 cm; lobes slightly spreading, rounded to oblong, 1/3 as long as corolla; stamens 10, shorter than corolla, filaments pubescent towards base; ovary densely scaly; style longer than stamens, glabrous. Capsule cylindric, ca. 13 mm, densely scaly. Fl. May–Jul.

Abies forests, mixed forests; 2900–4100 m. Xizang [Bhutan, NE India].

The pedicels are sometimes short in material that is otherwise typical Rhododendron xanthocodon. Both this species and its synonym, R. concatenans, were described from cultivated material, so the length of the pedicels and the number of flowers per inflorescence could well have been atypical. In distinguishing R. xanthocodon from R. cinnabarinum, the ratio between the leaf length and width is reasonably, though not exclusively, diagnostic.