Volume 13 > Part 1 > Year 2015 > Page 126 > Ericaceae > Rhododendron

1. Rhododendron ciliicalyx Franch.wfo-0001048064

Bull. Soc. Bot. France 33: 233. 1886; Cullen, Notes Roy. Gard. Edinburgh 39(1): 51. 1980; M.Y.Fang et al., Fl. China 14: 272. 2005. Plate XIII: 1–4.

Accepted Name : This is currently accepted.

Synonyms & Citations :

Description : Evergreen or semi-evergreen shrub to 2 m tall; branches distinct with scars, young branches covered by reddish-brown scales, with or without setose hairs. Leaves in pseudowhorls of 4–8, elliptic, oblong-elliptic, oblanceolate to obovate, (3–)4.2–9(–13.2) by 1.5–4(–6.4) cm, lower surface greyish to brownish, covered by dense scales, well-spaced to overlapping; base cuneate; margin entire and revolute, young leaves sometimes distinctly long ciliate; apex shortly acuminate to broadly obtuse-apiculate; midrib grooved above, prominent beneath, veins 6–8 on each side; petiole 0.7–1.5 cm long, usually hairy. Inflorescence subumbelliform on terminal branches, 3–5-flowered; floral buds ovoid, 3–4 cm long, bracts ovate-ciliate. Flowers white, pale pink or pinkish-white (before opening); bracts narrowly spathulate, to 3.5 cm long, scattered with scales, margin white ciliate. Calyx small, 2–3 mm long, unequally 5-lobed, scaly, margin lax to densely ciliate, sometimes absent, rarely of distinct lobes and enlarged to 10 mm long after anthesis. Corolla funnel-shaped, 4–7 cm long, 5–9 cm across, 5-lobed; lobes (sub)rounded, 2.2–4 by 2.2–3 cm, subentire, (sub)undulate to crisped, with dense yellow spots forming a patch, outer surface with white pubescence at the basal part or glabrous and sparse with scales. Stamens 10, subequal; filaments 4–7.2 cm long, with white hairs in the lower quarter to half; anthers brownish-yellow, 5–6 mm long. Ovary impressed to tapering, oblong-ovoid, 4–5 mm long, with dense scales, 5-locular; styles 3.5–4 cm long, sometimes hairy at base; stigma capitate. Capsules straight to obliquely ovoid-cylindrical, rough, 1.7–2(–2.5) cm long; fruiting calyx lobes rarely enlarged to 6–10 mm long. Seeds 2–3 mm long.

Thailand : NORTHERN: Chiang Mai (Doi Chiang Dao, Doi Inthanon, Chong Thong, Doi Ang Khang, Doi Lang Ka, Doi Phi Pan Nam), Nan (Doi Phu Kha), Phitsanulok (Phu Hin Rong Kla); NORTH-EASTERN: Loei (Phu Luang, Phu Kradueng, Phu Ruea); EASTERN: Chaiyaphum (Phu Khiao).

Distribution : China (Yunnan – type), Vietnam, Laos.

Ecology : In open areas in montane forests, on limestone or sandstone, 1,000–2,010 m alt.

Vernacular : Kulap khao (กุหลาบขาว), kulap chiang dao (กุหลาบเชียงดาว), kham khao chiang dao (คำาขาวเชียงดาว), dok sam si (ดอกสามสี), mai (ไม), nom wua doi (นมวัวดอย).

Notes: I have decided to combine several species previously recognised in Thailand, namely Rhododendron ludwigianum, R. surasianum and R. lyi into a broad, variable species. Comparison of type specimens showed that specimens from Thailand and R. ciliicalyx are same entity. Thus, this name has been applied. It is different from R. veitchianum as indicated in the key. It should be noted that specimens from Phu Hin Rong Kla have enlarged calyx lobes, to 6–10 mm long, while those from other places have small lobes, ca 1 mm long.