Hydrangea heteromalla D. Don

Hydrangea heteromalla forms a species complex out of which a number of segregate species have been recognized. One of the present authors (Bartholomew) feels that species nos. 18-23 below all fall within the pattern of variation found in H. heteromalla, in the synonymy of which they would be better treated.

Shrubs or small trees, 2-5 m tall or more. Branchlets red-brown to brownish, pubescent, glabrescent, with a few elliptic lenticels. Petiole purplish red, 2-4 cm, pilose; leaf blade elliptic, broadly ovate, or oblong-ovate, 6-15 × 3-8 cm, papery or at base of inflorescence membranous, abaxially densely gray-white velutinous, adaxially yellow-brown strigose to subglabrous, secondary veins 7-9 on both sides of midvein, base shallowly cordate, obtuse, or truncate, margin densely serrulate or doubly serrate, apex acute to acuminate. Inflorescences corymbose cymes, 15-20 cm wide, to 27 cm wide in fruit, apex arcuate; peduncle present; branches 3, pubescent; bracts and bracteoles lanceolate to linear. Sterile flowers with sepals 4, white or yellowish, elliptic, broadly ovate, or broadly orbicular, 0.7-1.6 × 0.5-1.4 cm, base rounded to shallowly cordate, margin entire. Fertile flowers with calyx tube nearly funnelform to campanulate, 1-1.5 mm; teeth triangular, 0.5-1.5 mm. Petals white or yellowish, oblong-ovate, 1.8-2 mm. Stamens 10, unequal; anthers subglobose, ca. 0.6 mm. Ovary up to 1/2 superior. Styles 3 or 4, erect, subulate, 1-1.3 mm in fruit; stigmas small. Capsule ovoid-globose to subglobose, 2.5-3.5 mm in diam., projected apical part conical, 0.8-1.2 mm, ca. 1/3 as long as capsule body. Seeds yellow-brown, ellipsoid to oblong, slightly compressed, 0.7-1 mm, winged at both ends; wings 0.2-0.5 mm; seed coat striate veined. Fl. Jun-Jul, fr. Sep-Oct.

Shrubs or small trees, 3-10 m tall. Branchlets brown to gray-brown, thick, strigose, glabrescent, with lenticels; bark thick, peeled off into fragments. Petiole 2-6 cm; leaf blade abaxially dark yellow-green and adaxially brownish when dry, oblong-elliptic, oblong-ovate, or broadly ovate, 9-19 × 4-14 cm, papery to thickly so, abaxially densely glandular papillate and and crisped pilose, adaxially shortly strigose along veins, secondary veins 8-10 on both sides of midvein, erect or slightly curved near margin, plane on both surfaces, base broadly cuneate, rounded, or subtruncate, margin serrulate, apex acute to shortly acuminate. Inflorescences corymbose cymes, 12-25 cm wide; peduncle short; branches 3, thick, pubescent. Sterile flowers with sepals 3-5, pinkish to yellowish, ovate, obovate, or suborbicular, subequal, 1.2-2.5 × 1.2-2.4 cm, margin entire or apically few denticulate. Fertile flowers with calyx tube campanulate, ca. 1.2 mm; teeth triangular, ca. 1 mm. Petals greenish, oblong-ovate, 2.5-3 mm. Stamens 10, unequal; anthers subglobose, ca. 0.7 mm. Ovary almost 1/2 superior. Capsule ovoid-globose, ca. 3.5 mm in diam., projected apical part conical, ca. 1.5 mm, slightly shorter than calyx tube; persistent styles 3 or 4, clavate, ca. 1 mm. Seeds brown, narrowly ellipsoid to fusiform, slightly compressed, 1.5-2 mm including long wings at both ends; seed coat striate veined. Fl. Jul, fr. Sep.

Shrubs 2.5(-5) m tall. Branchlets black-brown, terete, glabrous or sparsely acicular hirsute, with elliptic lenticels. Petiole 2-4.5 cm, long pilose; leaf blade narrowly elliptic, ovate-lanceolate, or broadly ovate, slightly asymmetric, 13-16 × 4-5 cm, papery, abaxially sparsely appressed white acicular hirsute along veins, more densely so along midvein and secondary veins, adaxially sparsely strigose, secondary veins 7 or 8 on both sides of midvein, abaxially prominent, base cuneate to subacute, margin densely serrulate, apex acute to shortly acuminate. Inflorescences corymbose cymes, ca. 19 cm wide; peduncle short; branches 3, roughly long hairy; bracteoles linear. Sterile flowers with sepals 4, yellowish, broadly elliptic, broadly ovate, or broadly orbicular, 1-1.6 × 1-1.9 cm, margin entire. Fertile flowers with calyx teeth triangular, less than 1 mm in bud, slightly longer in fruit. Petals deep yellow, oblong, ca. 2 mm in bud. Stamens 10, unequal; anthers purple-blue. Ovary less than 1/2 superior. Styles 3, ca. 1 mm in fruit, apex subacute. Capsule ovoid-globose, ca. 2.5 mm in diam., projected apical part conical, ca. 1 mm, ca. 1/3 as long as capsule body. Seeds brown, fusiform, long and narrowly winged at both ends; seed coat striate veined. Fl. Jun-Jul, fr. Sep.

Himalaya (Garhwal to NEFA), S. Tibet, Assam, N. Burma, N. Indo-China, China.

Sichuan, S Xizang, Yunnan [Bhutan, NE India, Nepal, Sikkim].

Sichuan, Yunnan.

W Yunnan.

2400-3300 m

Forests or thickets on mountain slopes or tops; 2400-3400 m.

* Dense to sparse forests on mountain slopes or tops; 2300-3500 m.

* Sparse forests or thickets in valleys or on mountain slopes; 1900-2500 m.

Hydrangea heteromalla var. parviflora C. Marquand & Airy Shaw; H. khasiana J. D. Hooker & Thomson; H. mandarinorum Diels; H. vestita Wallich.