1 | Nut lenticular with the narrow edge against the rhachilla; spikelets much compressed; stigmas 2 |
1' | Nut trigonous or rounded (occasionally flattened with a wide face against the rhachilla); spikelets more or less elliptical in section; stigmas (2-)3 |
2 | Inflorescence a head of spikelets without rays |
2' | Inflorescence spreading, anthelate, with short to long rays |
3 | Head obviously terminal, up to 6 cm wide; far-creeping sand-dune plant |
3' | Head apparently lateral, flanked by an erect bract |
4 | Bracts 2-3, leaf-like; leaves well developed, flat; nut dark, trigonous |
4' | Bracts apparently solitary, terete and culm-like; leaf-blades reduced to an apiculus or when developed, thick, crescentiform or triangular; nut pale, compressed |
5 | Plants with thick far-creeping rhizomes |
5' | Plants with thin, or short, rhizomes, or rhizomes absent |
6 | Rays few, not more than 5 cm long; slender, montane plants |
6' | Rays numerous, 8-12(-20) cm long; tall, lowland plants |
7 | 3-6 bracts below inflorescence |
7' | 8 or more bracts in a condensed spiral below inflorescence |
8 | Spikelets not more than 5 mm long, in small round, dense spikes |
8' | Spikelets 7-40 mm long |
9 | Plant densely caespitose, without elongated rhizomes; glumes regularly and closely imbricate |
9' | Plant not densely caespitose, with slender tube-bearing rhizomes; glumes loosely imbricate |