Description from Flora of China
Caprifolium longiflorum Lindley, Edwards’s Bot. Reg. 15: t. 1232. 1829; Lonicera longituba H. T. Chang ex P. S. Hsu & H. J. Wang.
Climbers, subglabrous throughout but young branches and petioles sometimes slightly yellow-brown hairy. Branches solid or becoming hollow. Petiole 5-10 mm, interpetiolar line raised; leaf blade ovate or elliptic to lanceolate, 4-8.5 × 1.5-5 cm, leathery, venation pinnate or occasionally triplinerved, veins raised abaxially, base rounded to cuneate, apex acute to acuminate. Flowers paired, often clustered at apices of branchlets into lax racemes; peduncle 3-14 mm; bracts linear-lanceolate, 1-5 mm; bracteoles orbicular-ovate, ca. 1 mm, glabrous. Neighboring 2 ovaries free, oblong, ca. 3 mm, glabrous. Calyx lobes broadly triangular or lanceolate, to 1.5 mm, sometimes ciliate. Corolla bilabiate, white, later yellow, 5-9 cm, outside glabrous or with few scattered, spreading, long, glandular hairs or with stiff hairs; tube 3-6 cm, 2-3 mm in diam., inside pubescent, base not gibbous; upper lip 4-lobed to 2 mm; lower lip recurved to coiled. Stamens and style long exserted from corolla tube. Style hairy at base. Berries white to black. Fl. Mar-Sep, fr. Oct.
● Sparse forests, sunny places along roadsides on mountains; 1200-1700 m. Guangdong, Guangxi, Hainan, Yunnan.