BECKMANNIA GRAMINEA 735 



BOUTBLOUA 



S. cynosuroides Willd. Enum. 80. Stems 2-6 feet high, simple, smooth: 

 sheaths longer than the intemodes, those at the base of the stem crowded: ligules 

 a ring of hairs: leaves a foot long or more, 3-7 lines wide, scabrous on the mar- 

 gins, becoming involute in drying, attenuate into long slender tips: spikes 5-30, 

 2-5 inches long, often on peduncles 6-12 lines long, erect or ascending: rachis 

 rough on the margins: spikelets much imbricated, 6-7 lines long: empty glumes 

 2-4 lines long, awn-pointed or awned, strongly hispid- scabrous on the keel: 

 flowering glume as long as the first, the scabrous midrib terminating just below 

 the emarginate or 2-toothed apex: palet sometimes exceeding the glume. Along 

 streams, eastern Oregon to Nova Scotia and Texas. 



S. gracilis Trin. Mem. Acad. St. Petersb. vj, 110. Stems 1-3 feet high, 

 erect, smooth: sheaths longer than the intemodes, the lower ones crowded: 

 ligules a ring of short hairs: leaves 6-12 inches long, 1-3 lines wide, flat or in- 

 volute, attenuate into long tips: spikes 4-8, 1-2 inches long, appressed, more 

 or less peduncled: empty glumes 3-4 lines long, acute scabrous-hispid on the 

 keel, the first half as long as the second: flowering glume obtuse, slightly shorter 

 than the second one: palet obtuse, about equalling the glume. In wet mead- 

 ows, eastern Oregon to Brit. Columbia and Nebraska. 



18 BECKMANNIA Host. Gram. Austr. iii, 5. 



Tall erect grasses with flat leaves and erect spikes in a terminal 

 panicle. Spikelets one- or two-flowered, compressed-globose. 

 Glumes 3 or 4, the two lower empty membranous, saccate, obtuse 

 or abruptly acute : flowering glumes narrow, thin-membranous. 

 Palets hyaline, two-keeled. Stamens 3. Styles distinct, with 

 plumose stigmas. Grain free, enclosed in the glume and palet. 



B. erucaeformis Host 1. c. Glabrous throughout: stems often stout, 2-3 

 feet high, erect: sheaths longer than the internodes, loose: ligules 2-4 lines long, 

 obtuse, often lacerate: leaves 3-10 inches long, 2-4 lines wide, rough: panicle 

 4-10 inches long, simple or compound, the spikes about 6 lines long: spikelets 

 1-2 lines long, 1-2-flowered, closely imbricated in 2 rows on one side of a 

 fidttish rachis: glumes smooth, the first two saccate and empty, obtuse or 

 abruptly acute: flowering glumes acute, the lower usually awn-pointed. Com- 

 mon in ditches and along streams, California to Brit, Columbia and Iowa. 



19- BOUTELOUA Lag. Var. Cienc. y Litter Part 4, 134. 



Annual or perennial grasses with flat or convolute leaves and 

 numerous spikelets in one-sided spikes. Spikelets one- or tWo- 

 flowered, arranged in two rows on one side of a flat rachis, the 

 rachella extended beyond the base of the flowers, bearing 1-3 

 awns and 1-3 rudimentary glumes. Two lower glumes empty, 

 acute, keeled : flowering glumes broader, 3-toothed, the teeth awn- 

 pointed or awned. Palets hyaline, entire or toothed. Stamens 

 3. Styles distinct, with plumose stigmas. Grain free, oblong. 



B. oligostachya Ton-, Gray Man. ed 2, 553. Stems 6-13 inches high, 

 glabrous: sheaths shorter than the internodes: ligules a ring of short hairs: 

 leaves 1-4 inches long, 1 line wide or less, involute, at least at ttfe long slender 

 tips, smooth or scabrous: spikes 1-3, 1-2 inches long, often strongly curved, 

 the rachis terminating in a short inconspicuous point: spikelets numerous, 

 pectinately arranged, about 3 lines long, first glume hyaline, shorter than the 

 membranous second one which is scabrous and sometimes long-ciliate on the 

 keel: flowering glume pubescent, 3-cleft, the nerves terminating in awns: ra- 

 chella with a tuft of long hairs under the rudimentary glumes and awne. On 



