Description from Flora of China
Philadelphus pekinensis Ruprecht var. kansuensis Rehder in Rehder & E. H. Wilson, J. Arnold Arbor. 9: 49. 1928.
Shrubs 2-7 m tall. Branchlets of previous year gray-brown, those of current year dark purple, sparsely puberulous to glabrescent. Petiole 2-8 mm; leaf blade ovate or ovate-elliptic, 5-10 × 3-6.5 cm, or 3-5 × 1-2(-3) cm on flowering shoots, both surfaces glabrous or adaxially strigose, abaxially villous only along veins, veins 3-5, basifugal, base rounded or broadly cuneate, margin subentire or sparsely dentate, apex acuminate. Racemes 5-7-flowered; rachis purple, 2-8 cm, sparsely strigose; pedicels 4-8 mm. Calyx purple; tube campanulate, sparsely strigose; lobes ovate-deltoid, ca. 4 × 3 mm, apex acute. Corolla discoid; petals white, oblong-ovate, 1.2-1.5 × 1-1.3 cm. Stamens 28-30, longest ones ca. 9 mm. Disc setose at rim. Style divided for ca. 1/2 its length, 6-7 mm, base sometimes hairy; stigmas clavate, ca. 1 mm, shorter than anthers. Capsule obovoid, 6-8 × 4-5 mm. Seeds ca. 3 mm, shortly tailed. Fl. Jun-Jul, fr. Oct-Nov.
* Thickets; 2400-3500 m. Gansu, Qinghai, Shaanxi.