Description from Flora of China
Shrubs, 0.3-3 m tall; branches terete to flattened, with internodes developed to shortened, glabrescent or usually densely puberulent to pilosulous, becoming gray to grayish white, with buds resinous and distalmost internodes often covered with resin. Leaves opposite or rarely ternate, subsessile to petiolate; petiole to 0.5(-1) cm, densely puberulent or shortly pilosulous to glabrous; blade drying thinly leathery to stiffly papery, oblong-lanceolate, obovate-oblong, obovate, oblanceolate, or elliptic, 3-25 × 1.5-8 cm, adaxially shiny and glabrous or sometimes puberulent on principal veins, abaxially puberulent or pilosulous to glabrous, base cuneate to acute, apex acute to acuminate or obtuse then abruptly long acuminate; secondary veins 8-15 pairs, in abaxial axils often with pilosulous domatia; stipules calyptrate, cylindrical, 4-13 mm, splitting for ca. 3/4 their length, densely puberulent to glabrous. Flower solitary, terminal; peduncle 1-10 mm, puberulent or pilosulous to glabrous. Calyx puberulent or pilosulous to glabrous; ovary portion obconic or obovoid, 5-8 mm, with (5 or)6(-8) weak to developed longitudinal ridges; limb with basal tubular portion 3-5 mm; lobes (5 or)6(-8), lanceolate or linear-lanceolate to spatulate, 10-30 × 1-4 mm, often strongly keeled, acute. Corolla white to pale yellow, simple or in cultivation sometimes doubled, outside glabrous; tube 30-50 × 4-6 mm, cylindrical, in throat pilose; lobes (5 or)6(-8) or numerous when doubled, obovate or obovate-oblong, 15-40 × 6-28 mm, obtuse to rounded. Fruiting peduncles apparently not much elongating. Berry yellow or orange-yellow, ovoid, subglobose, or ellipsoid, 1.5-7 × 1.2-2 cm, with 5-9 longitudinal ridges, with persistent calyx lobes to 40 × 6 mm; seeds suborbicular, weakly angled, ca. 3.5 × 3 mm. Fl. Mar-Jul, fr. May-Feb.
This is one of the most commonly collected species of Rubiaceae in China. It is quite variable morphologically especially in leaf size, calyx lobe size, and corolla size. Several varieties have been recognized for Chinese plants (e.g., Qiu & Zhong, Fl. Zhejiang 6: 105. 1986) but are not clearly separated or widely accepted outside this region. The varieties recognized by W. C. Chen (in FRPS 71(1): 332-335. 1999) are outlined below for reference.
Thickets and forests at streamsides, on mountain slopes or hills, or in valleys or fields; near sea level to 1500 m. Anhui, Fujian, Guangdong, Guangxi, Guizhou, Hainan, Hebei, Hubei, Hunan, Jiangsu, Jiangxi, Shandong, Sichuan, Taiwan, Yunnan, Zhejiang; cultivated in Gansu, Hebei, Shanxi [Bhutan, Cambodia, India, Japan, N Korea, Laos, Nepal, Pakistan, Thailand, Vietnam; cultivated in Africa, Asia, Australia, Europe, North and South America, and Pacific islands].