28 POACEAE. 



the upper ones often staminate or wanting. Scales 4-several, rarely 3, the 

 2 outer empty, membranous, exceeding or shorter than the flowering geales, 

 persistent, the flowering scales 5-9-nerve(l, rounded on the back, the apex fre- 

 quently shortly 2-toothed, the scales enclosing perfect flowers and bearing a 

 dorsal twisted geniculate awn, the upper empty ones or those infolding stami- 

 nate flowers awnless; palet 2-cleft or 2-toothed, narrow. Stamens 3. Styles 

 distinct. Grain deeply furrowed, usually pubescent. 



1. A. sativa L. Annual. Stems 8-15 dm. tall: leaf -blades flat, 2.5 dm. long 

 or less, 5-10 mm. wide or more: panicle usually 1.5-4 dm. long: empty scales 

 of the spikelet 2-3 cm. long, acuminate, the flowering ones shorter, awned or 

 awnless. — Common in fields and waste places and on roadsides. Nat. of Eu. 

 — Sum. — Oat. 



31. ABRHENATHERUM Beauv. Tall perennial grasses, with flat leaf- 

 blades and terminal open or contracted panicles. Spikelets 2-flowered, the 

 lower flower staminate, the upper one perfect or pistillate, the rachilla articu- 

 lated above the empty scales and prolonged beyond the flowers. Scales 4, the 

 2 outer empty, persistent, thin-membranous, keeled, the flowering scales more 

 rigid, somewhat toothed at the apex, the lower one bearing near the base a 

 long dorsal twisted and geniculate awn, the upper scale awnless, or short- 

 awned below the apex; palet 2-keeled, hyaline, narrow. Stamens 3. Styles 

 short, distinct. Stigmas plumose. Grain hardly sulcate. 



1. A. elatius (L.) Beauv. Stems 6-12 dm. tall, leaf-blades 6-30 cm. long, 

 2-8 mm. wide: panicle 1-3 dm. long: empty scales of the spikelet unequal, 

 the flowering scales about 8 mm. long. [A. avenaceum Beauv.] — M. Rather 

 common, in fields and waste places. Nat. of Eu. — Sum. — Tall oat-grass. 



32. DANTHONIA DC. Usually perennial grasses, various in habit, with 

 flat or convolute leaf-blades and terminal dense and contracted or open diffuse 

 panicles. Spikelets 2-many-flowered, the flowers perfect or the upper ones 

 staminate, the rachilla pilose, articulated between the scales and prolonged 

 beyond them. Scales 5-many, the 2 outer empty, persistent, usually extending 

 beyond the flowering scales, rarely shorter, keeled, acute or acuminate, the 

 flowering scales rounded on the back, the margins often ciliate, 2-toothed at 

 the apex, the teeth often awned, with an awn arising between the teeth which 

 is more or less flattened and very often twisted at the base and frequently 

 geniculate, the remaining scales often small and enclosing a palet only, or 

 empty; palet obtuse or 2-toothed, 2-keeled, hyaline. Stamens 3. Styles distinct. 

 Stigmas plumose. 



1. D. spicata (L.) Beauv. Stems 3-8 dm. tall: leaf -blades 2 mm. wide or less, 

 usually involute, the lower ones 1-1.5 dm. long: panicle 2-5 em. long: spikelets 

 5-8-flowered, the empty scales 8-10 mm. long, the flowering scales broadly 

 oblong, sparingly appressed-pubescent with silky hairs. — Eather common, in 

 dry soil, especially in pastures and on dry hills. — Sum. — Wild oat-grass. 



33. SPAHTINA Schreb. Often tall grasses, with flat or convolute leaf- 

 blades and spicate inflorescence, the spikes one-sided, the rachis extending 

 beyond the spikelets. Spikelets 1-flowered, sessile or nearly so, much crowded 

 and imbricated in 2 rows. Scales 3, firm-membranous, the 2 outer empty, 

 narrow, very unequal, keeled, the flowering scale equalling or a little longer and 



