23. Galium humifusum M. Bieberstein, Fl. Taur.-Caucas. 1: 104. 1808.
蔓生拉拉藤 man sheng la la teng
Asperula humifusa (M. Bieberstein) Besser.
Herbs, perennial, sometimes slightly woody at base, clambering to procumbent, from a thick rootstock with slender, trailing reddish rhizomes. Stems up to 1 m tall, 4-angled to subterete, often caespitose, glabrescent to white pilosulous, hirtellous, and/or pilose often with mixed trichome types, smooth or sparsely scaberulous. Leaves in whorls of 6-10, sessile, frequently reflexed; blade drying papery, from linear and narrowly oblong-oblanceolate to oblong-elliptic or ligulate, (5-)10-28(-32) × (1-)1.5-3(-6) mm, adaxially glabrous and scaberulous, abaxially glabrous to densely white pilosulous or -pilose, base straight to cuneate, margin antrorsely aculeolate and usually markedly revolute, apex obtuse to acute and mucronate with tip to 2 mm; vein 1. Inflorescences with numerous terminal and axillary, congested to fasciculate, leaflike and many-flowered cymes; peduncles glabrous to hirtellous and/or pilosulous, with reduced leaves and leaflike bracts, 1.5-3 mm; pedicels 1-4 mm. Ovary ellipsoid, 0.8-1 mm, glabrous to hispidulous with straight trichomes. Corolla yellowish white to white, funnelform, 1.5-2.5 × 2.5-3 mm, glabrous to sometimes hairy on outside; lobes 4, ca. 1/2 as long as tube, triangular-ovate, acute to apiculate. Mericarps ellipsoid to reniform, 1-1.5 × 1.5-2 mm, glabrous and smooth, granulate or hispidulous, becoming separated in middle as fruit expand but remaining attached at top and bottom. Fl. and fr. May-Oct.
Riversides and beaches, forests, grasslands, farmland sides, wastelands, meadows, mountain slopes; 400-2200 m. Xinjiang [Afghanistan, Kazakhstan, Mongolia, Pakistan, Russia, Turkistan; SW Asia (Armenia, Azerbaijan, Georgia, Iran, Iraq), E Europe (Balkan Peninsula, Ukraine)].
This species has often been included in Asperula (e.g., Pobedimova et al., Fl. URSS 23: 276. 1958) because of its funnelform, relatively large, white corollas, but its affinities are clearly with members of Galium, particularly G. verum, though the flowers are distinct. Rarely the two species form a hybrid, which has been called G. ×himmelbauerianum (Ronniger) Soó, and both should be placed into G. sect. Galium.
Galium humifusum is "a widespread diploid species, very variable due to modificational plasticity and genetic diversity" (Ehrendorfer et al., Fl. Iranica 176: 197. 2005), but at present it does not appear possible to recognize infraspecific taxa.