Click the number at the start of a key lead to highlight both that lead and its corresponding lead. Click again to show only the two highlighted leads. Click a third time to return to the full key with the selected leads still highlighted.
1 Glumes and sterile lemmas keeled along midvein; apices of fertile lemmas with a minute tuft of stiff hairs; panicles < 1 to > 20 cm wide, 9-40 cm long; leaf blades 8-50 cm long, 2-12 mm wide, flat (sometimes drying involute); culms wiry to stout.
2 Plants with rhizomes; fertile lemma 1.6-4.0 mm long.
3 Rhizomes short and stout, usually < 4 cm long, > 4 mm wide and ascending; spikelets (2.5-) 2.7-3.9 mm long, acuminate, often falcate distally; first glume with 3-5 prominent nerves; leaves to 50 cm long and 18 mm wide
3 Rhizomes long and slender, usually > 3 cm long, < 5 mm wide and spreading; spikelets 2.2-2.8 mm long, acute to short-acuminate, not noticeably falcate distally; first glume with 1-3 prominent nerves; leaves to 30 (-40) cm long and 10 mm wide
5Ligule of white hairs 0.5-3 mm long; culms to 1 m long; cauline blades 2-8 mm wide, usually pilose adaxially near the base; spikelets 2.0-4.0 mm long; upper leaves usually shorter than the panicle.
6 Ligules 0.5-1.5 mm long; spikelets 2.4-4.0 mm long, 3.5-5× as long as wide, erect on pedicels; first glume 1.3-2.9 mm long, > ½-¾ as long as the spikelet
6 Ligules 1-3 mm long; spikelets 2.4-4.0 mm long, 2.5-4 × as long as wide, often obliquely set on pedicels; first glume 0.9-1.4 mm long, about 2/5-1/2 as long as the spikelet
5Ligule a tawny membrane 0.5-1.0 mm long, often erose or lacerate, or with a minute ciliatefringe; culms to 1.8 m long; cauline blades 4-12 mm wide, usually glabrous; spikelets 1.6-2.8 mm long; upper leaves usually equaling or exceeding the panicle.
7 Spikelets 2.4-2.8 mm long, long-acuminate, usually < 0.7 mm wide; fertile lemma often conspicuously stipitate