This section is from the book "An Illustrated Flora Of The Northern United States, Canada And The British Possessions Vol1", by Nathaniel Lord Britton, Addison Brown. Also available from Amazon: An Illustrated Flora of the Northern United States, Canada and the British Possessions. 3 Volume Set..
A perennial grass, with soft flat leaf-blades and an open panicle. Spikelets usually 2-flovvered. Two lower scales empty, thin-membranous, much shorter than the flowering ones, unequal, rounded or obtuse at the apex; flowering scales membranous, erose-truncate. Palet barely shorter than the scale. Stamens 3. Styles distinct. Stigmas plumose. [Greek, in allusion to the erose top of the flowering scales.]
A monotypic genus of arctic and mountainous regions of the northern hemisphere. Type species: Aira aquatica L.
Aira aquatica L. Sp. PI. 64. 1753.
Catabrosa aquatica Beauv. Agrost. 157. 1812.
Smooth and glabrous, culms 4'-2° tall, erect, from a creeping base, bright green, flaccid. Sheaths usually overlapping, loose; ligule 1 1/2"-2 1/2" long; blades 1 1/2'- 5' long, 1"-3" wide, flat, obtuse; panicle 1'-8' in length, open, the branches whorled, spreading or ascending, very slender, 1/2'-2' long; 'spikelets 1 1/4"- 1 3/4" long, the empty scales rounded or obtuse, the first about half as long as the second, which is crenulate on the margins; flowering scales 1"- 1 1/4" long, 3-nerved, erose-truncate at the apex.