226. Rhododendron platypodum Diels, Bot. Jahrb. Syst. 29: 511. 1900.
阔柄杜鹃 kuo bing du juan
Shrubs or small trees, 2–8 m tall; bark gray; branchlets stout, 6–10 mm in diam., with slight gray waxy dust. Petiole flat, 1–2 cm, up to 10 mm wide; leaf blade thickly leathery, broadly elliptic or suborbicular, 9–13 × 5.5–7.5 cm; base obtuse to rounded, decurrent along petioles; apex rounded, sometimes apiculate; abaxial surface with minute punctulate hair-bases when mature, otherwise glabrous; adaxial surface dark green; midrib slightly raised on both surfaces; lateral veins 12–18-paired, glabrous. Inflorescence lax, 12–15-flowered; rachis 40–60 mm, slightly glandular. Pedicel 1.7–3.7 cm, glabrous or glandular; calyx rimlike, fleshy; lobes 7, ca. 2 mm, undulate, glabrous; corolla funnel-campanulate, pinkish, lacking markings; lobes 7, suborbicular, ca. 1.6 × 2–2.5 cm; stamens 12–14(–16), filaments puberulent near base; ovary ovoid, ca. 6 mm, densely glandular-hairy; style ca. 3.7 cm, glandular-hairy to tip, stigma discoid, 3–5 mm in diam. Capsule cylindric, ca. 15 × 8–9 mm, densely glandular. Fl. Apr–May, fr. Aug–Sep.
Forests, thickets, rocky slopes; 1800–2200 m. Chongqing (Nanchuan).
The present authors have seen no material of Rhododendron yuefengense G. Z. Li (Guihaia 15: 293. 1995), described from Guangxi. It is very close to, and probably a synonym of, R. platypodum, apparently differing only in its smaller stature (0.5–1.5 m tall) and glabrous stamens. The other differences quoted in the original description do not significantly differentiate between the two species.
Following Hans Eiberg (pers. comm. to Libing Zhang), there are many important traits between Rhododendron platypodum and R. yuefengense, so they are two different species:
- glands on stamens on R. platypodum, not on R. yuefengense
- many glands on calyx and pedicle (R. yuenfengense)
- longer petiole on R. yuefengense
- different flowering time
- creeping growth on R. yuefengense - upright on R. platypodum
See his homepage for more information:
http://www.rhododendron.dk/platypodum.html
http://www.rhododendron.dk/yuefengense.html
