3. Bolboschoenus affinis (Roth) Drobow, Trudy Bot. Muz. Imp. Akad. Nauk. 16: 139. 1916.
球穗三棱草 qiu sui san leng cao
Scirpus affinis Roth in Roemer & Schultes, Syst. Veg. 2: 140. 1817; Bolboschoenus popovii T. V. Egorova; B. strobilinus (Roxburgh) V. I. Kreczetowicz; S. maritimus Linnaeus subsp. affinis (Roth) T. Koyama; S. maritimus var. affinis (Roth) C. B. Clarke; S. strobilinus Roxburgh.
Rhizomes creeping, terminated by a small ovoid tuber. Culms 10-50 cm tall, 3-angled, smooth. Leaf blade linear, 1-4 mm wide, flat, ± stiff, apical ones longer than or as long as culm. Involucral bracts 2 or 3, leaflike, overtopping inflorescence. Inflorescences of 1-10 spikelets, capitate, rarely with short rays. Spikelets ovoid, 10-16 × 3.5-7 mm, many flowered. Glumes pale yellow, oblong-ovate, 5-6 mm, membranous, abaxially ± pubescent, 1-veined costa excurrent into an awn, apex lacerate. Perianth bristles 6, ca. 1/2 as long as nutlet, retrorsely scabrous. Stamens 3; anthers linear-oblong, ca. 1 mm; connective apex conic, ca. 0.5 mm. Style slender; stigmas 2. Nutlet yellowish white but becoming dark brown at maturity, broadly obovoid, ca. 2.5 mm, biconvex, shiny. Fl. and fr. Jun-Sep.
Lake margins, swampy places (often alkaline), wood margins; 1000-2900 m. Gansu, W Nei Mongol, Ningxia, Qinghai, Xinjiang [Afghanistan, Cambodia, India, Japan, Kazakhstan, Laos, Mongolia, Pakistan, Russia, Thailand, Turkmenistan, Uzbekistan, Vietnam; SW Asia, Europe].
This taxon is part of an inadequately studied worldwide complex centered around Bolboschoenus maritimus.