115. Rhododendron riparioides (Cullen) Cubey, Flora of China. 14: 297. 2005.
雪龙美被杜鹃 xue long mei bei du juan
Basionym: Rhododendron calostrotum subsp. riparioides Cullen, Notes Roy. Bot. Gard. Edinburgh 36: 123. 1978
Basionym: Rhododendron calostrotum I. B. Balfour & Kingdon Ward subsp. riparioides Cullen, Notes Roy. Bot. Gard. Edinburgh 36: 123. 1978; R. calostrotum var. riparioides (Cullen) R. C. Fang.
Upright shrubs, to 1.5 m tall; young shoots with dense stipitate or sessile scales, strap-shaped setae absent. Petiole 2–6 mm, densely scaly, without strap-shaped setae; leaf blade elliptic to ovate-elliptic, (1.2–)1.8–3.8 × (0.6–)0.8–2 cm; margin lacking strap-shaped setae; apex generally acute; abaxial surface scales overlapping, arranged in 2–3 tiers, orange-pink; adaxial surface greenish blue-gray, matt. Inflorescence terminal, to 5-flowered. Pedicel 0.8–2 cm, lacking multicellular hairs; calyx reddish purple or pale red, 5-lobed to the base; lobes 4–7 mm, elliptic, ovate or nearly rounded, ± pubescent or glabrous; corolla openly funnel-campanulate, bright purple, with darker flecks; outer surface not scaly, pubescent; stamens 10, 1.2–1.8 cm; style longer than stamens, glabrous or pubescent at base. Capsule not known.
Rocks above Abies forests; 3600–4800 m. NW Yunnan.
Janet C. Cubey (WSY) is acknowledged for her contribution to the account of this species. Recent research by Cubey (A cytological and morphological taxonomic study of Rhododendron L. subsection Saluenensia. PhD thesis, University of Liverpool. 2003) has shown that R. calostrotum var. (or subsp.) riparioides is consistently tetraploid (2n = 52*) and is therefore genetically isolated from the diploid R. calostrotum and its var. calciphilum (2n = 26). This distinction is confirmed by the morphological differences mentioned above. For these reasons Cubey here proposes the name R. riparioides.