9. Glyceria triflora (Korshinsky) Komarov, Fl. URSS. 2: 459. 1934.
东北甜茅 dong bei tian mao
Glyceria aquatica (Linnaeus) Wahlberg var. triflora Korshinsky, Trudy Imp. S.-Peterburgsk. Bot. Sada 12: 418. 1892; G. arundinacea Kunth subsp. triflora (Korshinsky) Tzvelev; G. effusa Kitagawa; G. kamtschatica Komarov; G. maxima (Homberg) Hartman subsp. triflora (Korshinsky) Hultén; G. triflora var. effusa (Kitagawa) Z. L. Wu.
Perennial, rhizomatous; rhizomes long, thick. Culms stout, 50–150 cm tall, 4–8 mm in diam. Leaf sheaths smooth, lower sheaths with transverse veinlets; leaf blades flat, 15–25 cm × 5–10 mm, abaxial surface green, smooth or scaberulous, adaxial surface grayish green, finely papillose, apex acuminate; ligule 2–4 mm, margin cuspidate in middle. Panicle open, obovate in outline, 20–30 cm, shortly exserted, spikelets many; branches 3–4 per node, ascending or spreading, smooth or slightly scabrid. Spikelets elliptic or oblong, 5–8 mm, florets 3–8, green or purplish at maturity; glumes ovate, membranous, 1-veined, lower glume 1.5–2 mm, upper glume 2–3 mm, obtuse or subacute; lemmas elliptic-oblong, 2–3.5 mm, thinly herbaceous, 7-veined, veins finely scabrid, apex hardly membranous, obtuse; palea as long as or slightly shorter than lemma, keels wingless, scabrid, apex truncate. Stamens 3, anthers 0.9–1.5 mm. Fl. and fr. Jun–Sep. 2n = 20.
Swamps, marshy ground near streams and lakes; 200–3300 m. Hebei, Heilongjiang, Nei Mongol, Shaanxi, ?Sichuan, ?Yunnan [Kazakhstan, Korea, Mongolia, Russia (Far East, Siberia); Europe (Ural Mountains)].
This species is an Asian element of the Glyceria arundinacea complex and is sometimes included as a subspecies of the latter. Glyceria arundinacea Kunth s.s. occurs in C Europe and the Caucasus and is distinguished by its densely scabrid adaxial leaf surface and panicle branches, and shorter glumes. The North American species G. grandis S. Watson, with slightly smaller glumes and anthers, also belongs to this complex.
The records from Sichuan and Yunnan have not been confirmed.