✲ Spikelets awnless.
† A small aquatic grass with prostrate habit and two-flowered spikelets with broad truncate glumes and paleæ.
Catabrosa aquatica, Beauv. (Fig. [4]).
The two-flowered spikelets distinguish it at once from Glyceria aquatica, to say nothing of its softer and smoother texture and small stature. Poa trivialis may have two flowers, but it is an erect meadow-grass, with keeled and pointed glumes and paleæ. Aira and Agrostis are awned, or differ entirely in habit.
†† Spikelets with at least three or four, but usually more flowers.
⊙ A perennial field-grass with few large, compressed, bluntly triangular or ovate spikelets, dangling at the end of capillary branchlets; with membranous, loosely imbricated, concave and inflated paleæ and glumes, and 6-8 flowers.
Briza media, L.
The much rarer B. minor, L. is an annual and smaller.
⊙⊙ Spikelets small and numerous, more or less elongated and pointed, not dangling: glumes and paleæ not inflated.