Description from Flora of China
Caprifolium microphyllum (Willdenow ex Roemer & Schultes) Kuntze; Lonicera oiwakensis Hayata; Xylosteon sieversianum Ruprecht.
Shrubs, deciduous, 1-3 m tall. Branches with solid pith. Winter buds with 3-6 pairs of scales, rounded to acute. Petiole 1-2 mm; leaf blade abaxially often gray-white, sometimes with membranous domatia in vein axils, obovate to elliptic or oblong, 5-22 × 5-13 mm, both surfaces densely puberulent to subglabrous, base cuneate, apex obtuse or ± acute, sometimes mucronate. Inflorescences axillary, paired flowers; peduncles 5-12 mm, usually nodding; bracts subulate, exceeding ovaries, bracteoles absent. Neighboring 2 ovaries fused completely or at least to middle, glabrous. Calyx rimlike to lobed. Corolla bilabiate, white to yellow, sometimes tinged pink; tube 7-10 mm, outside hairy or glabrous, gibbous toward base on ventral side; lobes oblong, 3-7 mm, upper 4 lobes erect, lower one recurved. Stamens inserted at mouth of corolla, together with style exserted; filaments and style glabrous or with spreading hairs. Ovaries 3-locular, with 4 or 5 ovules per locule. Berry red or orange-yellow, globose, 5-6 mm in diam.; seeds yellowish brown, oblong or ovoid-ellipsoid, 2.5-3 mm, smooth. Fl. Apr-Jun(-Jul), fr. Jul-Aug(-Sep). 2n = 18.
Rocky slopes, grasslands, thickets, sparse forests, forest margins; 1100-3600(-4100) m. Gansu, W Hebei, ?Henan, Nei Mongol, Ningxia, Qinghai, Shanxi, Taiwan, Xinjiang, Xizang [Afghanistan, NW India, Kazakhstan, Kyrgyzstan, Mongolia, Pakistan, Russia].