Description from Flora of China
Shrubs 0.3-1 m tall. Branchlets purple-red to red-brown, slender, terete, sparsely crisped pubescent when young, glabrescent; bark peeled off into fragments when old. Petiole 3-12 mm, sparsely pubescent; leaf blade abaxially pale to purplish, adaxially yellow-green, lanceolate, ovate-lanceolate, or elliptic, 3-8.5 × 1-3 cm, membranous to thinly papery, both surfaces sparsely pubescent or glabrescent, secondary veins 4-6 on both sides of midvein, thin, abaxially slightly conspicuous, base cuneate to subacute, margin irregularly serrate from base or middle to distal part or sometimes subentire, apex shortly caudate-acuminate. Inflorescences corymbose cymes, 2-6 × 2-6 cm; peduncle short or absent; branches (1-)3, slender, sparsely pubescent. Sterile flowers absent. Fertile flowers few. Calyx tube shallowly cupular, ca. 1 mm; teeth ovate-lanceolate to ovate, 1-1.5 mm. Petals yellow-green, narrowly elliptic to oblanceolate, 3-4 × 0.7-1 mm, base shortly clawed. Stamens 10, subequal, slightly shorter than petals; anthers oblong, ca. 1.5 mm. Ovary ca. 1/2 superior. Styles 3 or 4, erect or slightly spreading, 1-1.5 mm in fruit; stigmas capitate, enlarged. Capsule cupular, 3-4 mm in diam., projected apical part 1.5-2.5 mm, equaling or slightly longer than calyx tube. Seeds yellowish, oblong to obovoid, ca. 0.5 × 0.3-0.5 mm, wingless; seed coat net veined. Fl. May, fr. Oct.
One of the present authors (Bartholomew) believes that this species is not distinct from Hydrangea coenobialis.
* Dense forests or thickets in valleys or on mountain slopes; 400-700 m. Hunan, Jiangxi.