45. Rhododendron trichanthum Rehder, J. Arnold Arbor. 26: 480. 1945.
长毛杜鹃 chang mao du juan
Rhododendron villosum Hemsley & E. H. Wilson, Bull. Misc. Inform. Kew 1910: 119. 1910, not Roth (1807).
Shrubs, 1–3 m tall; young shoots scaly, densely hispid and pubescent. Petiole 4–10 mm, scaly, densely hispid and pubescent; leaf blade oblong-lanceolate and ovate-lanceolate, 4–11 × 1.5–3.5 cm; base cuneate to rounded; apex acuminate or acute; abaxial surface scales 1–4 × their own diameter apart, unequal, yellowish brown; hispid and pubescent, densely so along midrib; adaxial surface sparsely scaly, hispid to pubescent or glabrous. Inflorescence terminal, umbellate or shortly racemose, 2- or 3-flowered; rachis ca. 3 mm. Pedicel 1–1.5 cm, scaly, densely hairy; calyx 0.5–1 mm, scaly, densely hispid; corolla broadly funnelform-campanulate, pale purple, rose red or white, 2.5–3.5 cm, outer surface scaly, tube hispid; stamens unequal, some longer than corolla; filaments densely pubescent below; ovary 5-locular, densely scaly, hispid; style longer than corolla, usually glabrous, rarely pubescent at base. Capsule cylindric, 10–15 mm, scaly, hispid, rarely without hairs. Fl. May–Jun, fr. Sep.
Forests, thickets; 1600–3700 m. W Sichuan.
Rhododendron ×lochmium I. B. Balfour (Notes Roy. Bot. Gard. Edinburgh 11: 90. 1919) was described from cultivated material derived from seed of R. trichanthum collected in Sichuan. It was considered to be a hybrid between R. trichanthum and, most probably, R. davidsonianum by Cullen (Notes Roy. Bot. Gard. Edinburgh 39: 80. 1980).
Rhododendron ×trichophorum I. B. Balfour (Notes Roy. Bot. Gard. Edinburgh 12: 173. 1920), described from Sichuan, was considered to be a hybrid between R. trichanthum and R. augustinii by Cullen (loc. cit.: 75).