726 GRAMlNEiE ageobtis 



lower exceeding the internodes : ligules almost herbaceous, 3-4 lines long, 

 obtuse: panicle rather dense, narrow, erect, 7-10 inches long, its short 

 branches ereqt: spikelets t-l}4 lines long, narrowly lanceolate, turgid : 

 outer glomes unequul, hispidjllous throughout and hispid on the keel: 1-2 

 lines long : flowering glume broadly oblong, minutely dentate at the trun- 

 cate apex, thin-membranous, 5-nerved to the apex, % line long : palet min- 

 ute or wapting. In moist placesl Alaska to California. 



A. densiflora "Vasey Cont. Nat. Herb. 3, 702. A tufted annual : stems 

 erect or g0niculate at the lower nodes Smooth, 9-12 inches high : sheaths 

 rather loose, nearly smooth, crowded below, longer thail the internodes : 

 ligules 2 lines long, obtuse : leaves flat or folded, 2-3 lines wide, hispidulous 

 on both sides, rather thick and rigid, erect tapering to the apex: panicle 

 dense, 2-3 inches long, its scabrous branches glomerate : empty glulnes 114 

 lines long, nearly equal, acuminate, carinate and hispidulous on the back : 

 flowering glume oblong, truncate, smooth except a minute tuft of white 

 hairs on the ventral side at base, 5-nerved, nearly 1 line long, with or 

 without a slender awn a line or less long near the apex : palet wanting. 

 Washington to California. 



A. microphylla Rteud. Syn. PI. Gram. 164. Loosely tufted annual : 

 stems slender, erect, 6-15 inches high, often branched at'the base : sheaths 

 nearly smooth, closed, shorter than the internodes : ligules 1-2 lines long, 

 usually lacerate : leaves erect, flat or loosely involute, 1-3 inches long : 

 panicle spike-like 1-3 inches long, light green or putplish, its branches 5-6 

 lines long : empty glumes nearly equal, 1)^-2 lines long, subulate-pointed, 

 hispid on the keel, 1-nerved : flowering glume broadly oblong, 4-toothed 

 at the. apex, thin, a line or less long, with a slender awn 2-3 lines long on 

 its back above the middle : palet wanting. In the coast ranges, Oregon 

 and California. 



A. grandtB Trin. Agroat. ii, 70. Stems erect, 1-2 feet high: sheaths 

 smooth, much shorter than the internodes : ligule about 2 lines long, acute : 

 leaves 2-8 in(jhea long, 1-3 lines wide : panicle usually ample, 4-8 inches 

 long, erect, dense, more or less interrupted below, its short branches erect: 

 empty glumes ovate, acute or acuminate, IK Une long, the lower one scab- 

 rous on the keel: flowering glume similar to the outer ones. In moist 

 meadows, California to Washington. 



A. Vflrticillata Till. Trin. Sp. Gram, i, t. 36. Stems 1-2 feet long, 

 decumbent and taking root below, several of the lower nodes geniculate : 

 sheaths'loose, shorter than the internodes: ligules truncate, 1-2 lines long : 

 leaves short, flat, 1-3 lines wide^ roughish on the upper surface and mar- 

 gins : panicle 2-6 inches long, dense and spike-like, lobed and interrupted, 

 its short branches crowded and spikelet-bearing from the base: empty 

 glumes about equall, acute, roughened with minute pubescence: flow- 

 ering glume about half as long as the outer ones^ 5-nerved and minutely 

 5-toothed at the obtuse apex : palet nearly as long as the glume. In 

 difches and wet places, southern Oregon to California and Texas. 



A. tenuicalmis Nash A. tenuis Vasey. Loosely tufted : perennial : 

 stems slender, 6-10 inches high, somewhat geniculate below : leaves lr-2 

 Inches long, narrow, about 2 on the stem : ligules short : panicle pyramidal, 

 open, 2-3 inches long, its capillary branches in threes or fives below, the 

 longest an inch or more long, spreading or ascending : spikelets less than a 

 line long: emptj; glumes actite, purplish, the lower cue a little shorter and 

 broader: flowering glume thin, obtusish, 3-nerved above, a little shorter 

 than the outer ones, not awned : palet very minute or wanting. On dry 

 ridges, California to eastern Washington. 



A. Pringrlei Scribn. Am. Grasses i, 156. Stems erect or ascending, 

 1-2 feet long, from a stoloniferous perennial base : leaves flat, narrow, 

 rather rigid: panicle narrow, ' loosely flowered, 3-8 inches long: empty 



