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..
Annual or perennial grasses, rarely dioecious, from a few inches to several feet in height, the spikelets in contracted or open panicles. Spikelets 2-many-flowered, more or less flattened. Two lower scales empty, unequal, shorter than the flowering ones, keeled, 1-nerved, or the second 3-nerved; flowering scales membranous, keeled, 3-nerved; palets shorter than the scales, prominently 2-nerved or 2-keeled, usually persisting on the rachilla after the fruiting scale has fallen. Stamens 2 or 3. Styles distinct, short. Stigmas plumose. Grain free, loosely enclosed in the scale and palet. [Greek, signifying probably a Love-grass.]
A genus of about 120 species, widely distributed throughout all warm and temperate countries. Besides the following, some 15 others occur in the southern and western parts of North America. Type species: Briza Eragrostis L.
Culms not creeping; plants with perfect flowers.
Spikelets 2-5-flowered, 1"-1 1/2" long.
Culms branched only at base; pedicels and branches of panicle long and capillary.
Flowering scales 1 1/4"-1 1/2" long; culms rarely over 20', slender.
Flowering scales 2"-2 1/2" long; culms 2° tall or more, usually stout.
Culms branched above the base; pedicels and branches of the panicle short.
Spikelets 5-many-flowered, 1 1/2"-8" long.
Spikelets 3/4" wide or less.
Flowering scales thin, usually bright purplish, the lateral nerves faint or wanting;
spikelets about 1/2" wide.
Flowering scales firm, usually dull purple or green, the lateral nerves very prominent;
spikelets about 24" wide.
Spikelets 1" wide or more.
Lower flowering scales about 3/4" long; spikelets 1" wide.
Lower flowering scales 1"-1 1/4" long; spikelets 1 1/4"- 1 1/2" wide.
Spikelets not clustered.
Branches of the open panicle stiff, widely spreading, at least when old.
Pedicels long, commonly at least the length of the spikelets.
Pedicels commonly much shorter than the spikelets.
Blades elongated; branches of the panicle long and slender; spikelets scattered,
Blades not elongated; branches of the panicle short and stout, rigid, the spikelets
Branches of the elongated panicle erect or ascending, capillary.
Spikelets clustered on the very short erect or ascending branches.
Culms extensively creeping; plants dioecious.
Flowering scales less than 1" long, glabrous.
Flowering scales 1 1/2"- 2" long, pubescent.