Description from Flora of China
Rhododendron amamiense Ohwi; R. ellipticum Maximowicz (1888), not Hoffmannsegg (1826); R. ellipticum Maximowicz var. leptosanthum (Hayata) S. S. Ying; R. latoucheae var. amamiense (Ohwi) T. Yamazaki; R. latoucheae var. ionanthum (W. P. Fang) G. Z. Li; R. leiopodum Hayata; R. leptanthum Hayata (1915), not F. Mueller (1889); R. leptosanthum Hayata; R. tanakae Hayata; R. wilsoniae Hemsley & E. H. Wilson; R. wilsoniae var. ionanthum W. P. Fang.
Shrubs or small trees, 2–7 m tall; shoots stout. Petioles to 15 mm, glabrous; leaf blade narrowly elliptic-lanceolate oblanceolate or ovate-elliptic, 5–11(–13) × 1.4–5.5 cm; base cuneate to broadly cuneate; margin slightly revolute; apex acuminate; both surfaces glabrous; midrib impressed adaxially, obsolete abaxially; lateral veins net-veined, slightly prominent on both surfaces. Inflorescence subapical, 1(–2)-flowered. Pedicel stout, 2–3 cm, glabrous; calyx lobes obscure or fine and triangular, rarely linear, then to 10 mm, margin and apex finely ciliate; corolla funnelform, pink to white, 3.5–4.8 cm, lobes long-ovate, glabrous, emarginate; stamens 10, included in tube or partly exserted, filaments flat, puberulent below middle; ovary cylindric, truncate below insertion of style, 3.5–8 × 0.2–0.4 mm, dark brown, glabrous; style 4–8 cm, exserted, glabrous. Capsules cylindric, ca. 40 × 4 mm; style deciduous. Fl. Mar–May, fr. Sep–Oct.
Gao Lianming (pers. comm.) notes that field observations indicate that the degree of calyx development and the size of the leaves are variable, even within a single population. There is therefore no justification for maintaining Rhododendron ellipticum Maximowicz as distinct from R. latoucheae (and anyway the former name cannot be used because it is an illegitimate later homonym).
Mixed forests, rocky mountain slopes; 100–2700 m. Anhui, Fujian, Guangdong, Guangxi, Guizhou, Hubei, Hunan, Jiangxi, Sichuan, Taiwan, Zhejiang [Japan (including Ryukyu Islands)].