55. Galium tenuissimum M. Bieberstein, Fl. Taur.-Caucas. 1: 104. 1808.
纤细拉拉藤 xian xi la la teng
Herbs, annual, erect. Stems (10-)30-50(-60) cm tall, with strong, intricate and divaricate branching from base, 4-angled, usually retrorsely aculeolate, more rarely glabrescent to smooth. Leaves at middle stem region in whorls of 6-8, subsessile or sessile; blade drying papery, linear to oblanceolate, (4-)8-15(-20) × 0.5-1(-2) mm, mostly glabrous and sparsely to densely antrorsely aculeolate near margins and on veins abaxially, base straight to acute, apex acute to acuminate-aristate; vein 1. Inflorescences broadly paniculate, very lax and loosely divaricate, cymes axillary and terminal, with 3-11(-14) flowers; axes glabrous or sparsely hispidulous; bracts none or small, leaflike; pedicels 3-15 mm, strongly elongating in fruit up to 20 mm. Ovary obovoid to ellipsoid, ca. 0.8 mm, glabrous. Corolla whitish, pale yellow, or greenish, rotate to slightly cup-shaped, 1.5-2 mm in diam., glabrous; lobes 4, oblong-elliptic, acute to aristate. Mericarps ellipsoid to obovoid, ca. 1 × 1.25 mm, glabrous, smooth or ± tuberculate. Fl. and fr. May-Jul.
Open mountain slopes; 300-2800 m. Xinjiang (Xinyuan) [Kashmir, Kyrgyzstan, Pakistan, Russia, Turkmenistan; SW Asia (Armenia, Georgia, Iran, Iraq, Lebanon, Syria, Turkey), Europe (Balkan Peninsula, Hungary)].
Galium tenuissimum is a member of the annual G. sect. Microgalium, differentiated by antrorsely aculeolate leaf margins. It is widespread through SE Europe, SW and C Asia, and reaches its eastern limit in NW China.