Description from Flora of China
Herbs, perennial, climbing or procumbent to usually erect, 0.1-1 m tall, from a slender rootstock with purplish rhizomes. Stems somewhat stout, 4-angled, smooth, sparsely to densely hirsute, villous, or villosulous and often densely puberulent at nodes, angles thickened. Leaves in whorls of 4, subsessile or petiole to 1.5 mm; blade drying papery to leathery, green to gray, or dark brown, ovate to broadly elliptic, 6-30 × 3-20 mm, length/breadth index mostly 2 or less, sparsely to densely hirtellous, villosulous, or hispidulous to scaberulous at least on principal veins, abaxially often glandular-punctate and/or -striate, base rounded to acute, margins antrorsely ciliate to ciliolate and flat to thinly revolute, apex rounded to obtuse; principal veins palmate, 3(or 5). Inflorescences thyrsoid to paniculiform, with several- to many-flowered, 2-10 cm long cymes in uppermost leaf axils and terminal; peduncles glabrescent to sparsely scaberulous, hirtellous, puberulent, or villosulous; bracts narrowly spatulate to narrowly elliptic, 1-3 mm; pedicels 0.5-2.5 mm. Flowers dioecious, polygamo-dioecious, or sometimes ?hermaphroditic. Ovary obovoid, in staminate flowers ca. 0.5 mm and glabrous to scaberulous or sparsely strigillose, in pistillate and bisexual flowers 0.8-1 mm and usually moderately to densely strigillose, particularly on their lateral side. Corolla white or pale yellow, rotate, 2-2.5 mm in diam., glabrous; lobes 4, ovate-triangular, acute to rounded. Mericarps ellipsoid, 1-1.5 mm, with sparse to dense and spreading uncinate trichomes 0.5-0.8 mm, rarely scaberulous or glabrous. Fl. Apr-Aug(-Oct), fr. May-Dec.
Galium elegans is a widely ranging, polymorphic species that may not be completely distinct from several other related taxa. It is here circumscribed more narrowly than by Cufodontis (Oesterr. Bot. Z. 89: 228-232. 1940) and W. C. Chen (in FRPS 71(2): 242-245. 1999), which reduces its variation a bit. These aspects are discussed below.
Plants with narrower leaves are separated here as Galium yunnanense. This species comprises two of the varieties included by Cufodontis in G. elegans, i.e., G. elegans var. angustifolium and G. elegans var. nemorosum. Separation of the two taxa is not always easy, as transitional specimens occasionally occur.
Plants of Galium elegans with shortened pedicels and more congested cymes (e.g., from Sichuan, Shimian Xian) may approach the Himalayan G. confertum Royle ex J. D. Hooker.
Galium nephrostigmaticum was described as a species by Diels, an opinion still maintained by some authors. Here, it is treated as a variety of G. elegans, following W. C. Chen (Acta Phytotax. Sin. 28: 301. 1990) who referred to its glabrous to scaberulous ovaries and fruit, as noted in Diels’s protologue. In contrast to this, Cufodontis (loc. cit.) synonymized G. nephrostigmaticum with G. elegans var. elegans. In an extensive discussion he demonstrated that G. elegans is dioecious and that G. nephrostigmaticum was based on a male plant with staminate flowers and reduced glabrous to smooth ovaries and sessile stigmas. In contrast, pistillate flowers of G. elegans have hairy ovaries and fruit, well-developed styles, and reduced stamens. Thus, according to Cufodontis, G. nephrostigmaticum does not merit taxonomic recognition. Ehrendorfer et al. (Fl. Iranica 176: 177. 2005) did not contradict the conclusions of Cufodontis but noted that some plants of G. elegans are monoecious or have bisexual flowers. This shows that the reproductive biology of this species apparently is more complex than thought before. Provisionally, G. nephrostigmaticum is treated here as a variety, pending more detailed studies of this critical group.
The still uncertain relationships between Galium elegans on the Chinese mainland and G. formosense on Taiwan are discussed under the latter taxon. In the present treatment their separation is maintained provisionally.
The traditional varieties of Galium elegans are separated schematically by the density, type, and distribution of the indumentum on the vegetative organs and have doubtful taxonomic value. W. C. Chen in FRPS (loc. cit.) also used leaf size and apex shape as characters to differentiate these varieties. For reference and to facilitate comparison with other works, we present a key to these infraspecific taxa below.
Forests, thickets, meadows on mountain slopes, streamsides, open fields, on rocks; 200-3500 m. Anhui, Fujian, Gansu, Guangxi, Guizhou, Hunan, Qinghai, Sichuan, Taiwan, Xizang, Yunnan, Zhejiang [Bangladesh, Bhutan, India, Kashmir, Myanmar, Nepal, Pakistan, Thailand].