Description from Flora of China
Philadelphus pekinensis Ruprecht var. dasycalyx Rehder, J. Arnold Arbor. 1: 197. 1920.
Shrubs subscandent, ca. 3 m tall. Branchlets of previous year grayish brown, glabrous, those of current year brownish. Petiole 5-10 mm; leaf blade ovate or ovate-elliptic, 3-6(-8) × 1.2-3.5(-5) cm, abaxially glabrous or sparsely villous to glabrescent when young, adaxially glabrous or sparsely strigose on flowering shoots, veins 3-5, slightly basifugal, base broadly cuneate or obtuse, margin serrate, apex acute. Racemes 5-6(-8)-flowered, lowest ones rarely 3-flowered; rachis 2.5-5.5 cm, sparsely white villous; pedicels 4-5 mm, white villous. Calyx tube densely erect grayish white villous; lobes ovate, 5-6 × 2.5-3 mm, sparsely villous to glabrous, apex acute. Corolla discoid; petals white, obovate or broadly so, 1.2-1.5 × 1-1.2 cm. Stamens 25-34, longest ones ca. 7 mm. Disc and style glabrous, rarely villous. Style slightly divided at apex, ca. 6 mm; stigmas clavate, ca. 1.5 mm, shorter than anthers. Capsule obovoid, ca. 6 × 4.5 mm, with persistent calyx lobes at apex. Seeds ca. 3 mm, shortly tailed. Fl. May-Jun, fr. Jul-Sep.
* Coniferous forests, thickets; 700-2500 m. Gansu, Henan, Shaanxi, Shanxi.