Description from Flora of China
Herbs, perennial, erect, 20-65 cm tall. Stems 4-angled, usuually glabrous, rarely shortly hairy, hispidulous at nodes, angles thickened. Leaves in whorls of 4, sessile or subsessile; blade drying papery or thinly leathery, linear-lanceolate or lanceolate to ovate, (10-)15-40(-80) × (1-)3-15 mm, glabrous or sparsely puberulent to hispidulous and/or pilose, abaxially never with striate to punctate glandular idioblasts, base cuneate to subrounded, margins usually revolute and antrorsely scaberulous to hispidulous, apex acute or usually narrowly tapered then obtuse to rounded at very tip; principal veins palmate, 3. Inflorescences terminal, elongate or broadly paniculiform, 2-15 cm, with several- to many-flowered cymes in axils of uppermost leaves and terminal; peduncles glabrous or puberulent at nodes, smooth or scaberulous; bracts ligulate, lanceolate, or elliptic, 1-4 mm; pedicels 0.5-2 mm elongating in fruit to 3.5 mm. Ovary subglobose, 0.8-1 mm, glabrous or sparsely to densely strigillose to pilosulous. Corolla white or pale yellow, rotate, 3-4 mm in diam., glabrescent, lobed for 3/4 or more; lobes 4, ovate-lanceolate, acute. Mericarps subglobose, 1-2 mm, pericarp firmly attached but sometimes ± inflated, glabrous or ± densely hairy with ± appressed, ascending, or spreading, straight or curved, but hardly truly uncinate trichomes 0.3-0.5 mm. Fl. May-Aug(-Sep), fr. (May-)Jun-Oct.
The name Galium boreale, as used here in a wide sense, corresponds to a widespread and polymorphic, still insufficiently studied N Hemisphere polyploid complex (Ehrendorfer et al., Fl. Iranica 176: 179-181. 2005) within G. sect. Platygalium s.l. In China, another species of this section with much smaller flowers, G. kinuta, can be separated from this G. boreale aggregate only with difficulties, because the two are linked by intermediate (and possibly hybrid) populations (see under G. kinuta).
Within the Galium boreale aggregate and the flora of China, W. C. Chen (in FRPS 71(2): 260-263, 285. 1999) recognized only G. boreale Linnaeus s.l. with numerous infraspecific taxa and G. turkestanicum, whereas 11 species in three series were listed for the flora of the former Soviet Union by Pobedimova et al. (Fl. URSS 23: 345-354. 1958). From these only G. turkestanicum is fully accepted here (G. ussuriense and G. rubioides are cited as synonyms under G. boreale var. lanceolatum and G. boreale var. rubioides). Furthermore, and according to Pobedimova et al. (loc. cit.), G. amblyophyllum Schrenk, G. amurense Pobedimova, and G. septentrionale Roemer & Schultes can be expected to occur in China. With the exception of the briefly mentioned G. septentrionale, they were not considered by W. C. Chen in FRPS and are only mentioned here. As a competent treatment of the G. boreale aggregate is not yet possible, we follow the schematic taxonomic differentiation proposed by Cufodontis (Oesterr. Bot. Z. 89: 225-228. 1940) and accepted by W. C. Chen (loc. cit.). This scheme defines numerous varieties according to leaf shape and the density, type, and distribution of indumentum on leaves, ovaries, and fruit. These varieties form a morphologically ± continuous series, linking the extremes: G. boreale var. rubioides with large ovate leaves and a broadly paniculate inflorescence and G. boreale var. intermedium with much smaller lanceolate leaves and an elongated narrow inflorescence. The following key and short descriptions are presented here for reference, to facilitate comparison, and to stimulate future studies.
Open forests and thickets, mountain slopes, grasslands, meadows, open fields, ditch sides, river valleys and beaches, swamps, farmland sides, wastelands; 200-4600 m. Gansu, Hebei, Heilongjiang, Henan, Jilin, Liaoning, Nei Mongol, Ningxia, Qinghai, Shaanxi, Shandong, Shanxi, Sichuan, Xinjiang, Xizang, Yunnan [Afghanistan, India, Japan, Kashmir, Korea, Mongolia, Pakistan, Russia; SW Asia (Armenia, Iran), Europe, North America].