Description from Flora of China
Hydrangea pubinervis Rehder; H. xanthoneura var. lancifolia Rehder; H. xanthoneura var. setchuenensis Rehder; H. xanthoneura var. sikangensis Chun; H. xanthoneura var. wilsonii Rehder.
Shrubs or small trees, 1-7 m tall. First year's branchlets black-brown to gray-brown, glabrous or pilose, glabrescent, sometimes with lenticels. Second year's branchlets with lenticels; bark thick, not easily peeled off. Petiole 1.5-5 cm, pilose; leaf blade abaxially greenish, adaxially yellowish green, elliptic, oblong-ovate, or oblong-obovate, 8-18 × 3-10 cm, papery to thickly so, abaxially glabrous except grayish pubescent to densely slightly crisped villous along veins, adaxially strigose along veins, secondary veins 7 or 8 on both sides of midvein, erect and obliquely ascending, yellowish, base broadly cuneate to subrounded, margin densely serrate, apex acute to shortly acuminate. Inflorescences corymbose cymes, 10-20 cm wide, apex arcuate; branches 3, unequal with central one usually longer than others, pubescent. Sterile flowers with sepals 4(or 5), yellowish green, broadly elliptic to suborbicular, 1-3.5 × 1-2.5 cm. Fertile flowers with calyx tube shallowly cupular, ca. 1 mm; teeth triangular, equaling calyx tube. Petals white to greenish, oblong-ovate, ca. 2.5 mm. Stamens 10-13, unequal; anthers subglobose, ca. 0.5 mm. Ovary less than 1/2 superior. Styles 3 or 4, ca. 1 mm in fruit; stigmas narrowly ellipsoid, slightly enlarged. Capsule ovoid-globose, ca. 3 mm in diam., projected apical part conical, ca. 1 mm, ca. 1/3 as long as capsule body. Seeds brown to brownish, narrowly ellipsoid, ca. 2 mm, winged at both ends; wings ca. 0.5 mm; seed coat striate veined. Fl. Jun-Jul, fr. Sep-Oct.
* Dense to sparse forests or thickets on mountain slopes or tops or trailsides; 1600-3200 m. Guizhou, NW Hubei, Sichuan, Yunnan.