26 POACEAE. 



long, the scales very hispidulous, the outer ones about equal, acuminate and awn- 

 pointed, the flowering scale obtuse, the basal hairs from ^- its length, the awn 

 stout, exceeding or equalling the scale. [C. Nuttalliana Steud.] S. Bather 

 rare, in swamps. Schists. Sum. 



26. AGROSTIS L. Annual or perennial usually tufted grasses, with flat 

 or setaceous leaf -blades and terminal often slender contracted or open panicles 

 with numerous branches. Spikelets very numerous, small, 1-flowered, the rachilla 

 articulated above the empty scales. Scales 3, the 2 outer empty, persistent, 

 membranous, keeled, acute, awnless, the third one shorter, thin-hyaline, awnless, 

 or sometimes bearing a slender dorsal often geniculate awn, enclosing a perfect 

 flower and frequently also a short very thin hyaline palet rarely more than 

 as long as the scale, sometimes minute or wanting. Stamens usually 3. 

 Styles distinct, very short. Stigmas plumose. BENT-GRASS. 



Palet of the spikelet conspicuous, at least % as long as the scale. 



1. A. alba. 

 Palet inconspicuous, minute, or wanting. 



Stems weak, usually decumbent and often prostrate at the 

 base : leaf -blades lax : panicle oblong, the spikelets about 



1.5 mm. long. 2. A. Schweinitzii. 



Stems, and usually also the leaf-blades, erect. 



Branches of the panicle capillary, elongate, commonly 



dividing above the middle. 3. A. hyemalis. 



Branches of the panicle not elongate, dividing at the 



middle or below It. 4. A. perennans. 



1. A. alba L. Stems 2-8 dm. tall, often stolonif erous : leaf -blades 5-20 cm. 

 long, 2-6 mm. wide: panicle 5-23 cm. long, usually open, or sometimes con- 

 tracted after flowering, green or purplish: spikelets 2-2.5 mm. long, the empty 

 scales about equal, acute, hispidulous on the keel. Common, in fields and on 

 roadsides. Nat. of Eu. Sum. BED-TOP. 



2. A. Schweinitzii Trin. Stems 3-8 dm. long from a decumbent or prostrate 

 base, weak: leaf -blades 5-15 cm. long, 2-4 mm. wide, lax: panicle 1-2 dm. 

 long, open, oblong, its branches widely spreading, the branchlets and pedicels 

 divergent: spikelets 1.5-2 mm. long, the empty scales hispidulons on the keel. 

 S. Frequent, in woods and low grounds. Schists. Sum. and fall. THIN- 

 GRASS. M i 



3. A. hyemalis (Walt.) B.S.P. Stems 3-6 dm. tall, slender: leaf -blades 5-13 

 cm. long, 1-3 mm. wide, usually erect, roughish: panicle 1.5-6 dm. long, usually 

 purplish, the very rough capillary branches ascending or spreading, often droop- 

 ing, the lower ones 7-15 cm. long: spikelets 1.5-2 mm. long. [A. scdbra Willd.] 

 Common, on dry banks. Sum. HAIR-GRASS. 



4. A. perennans (Walt.) Tuckerm. Stems 3-9 dm. tall, tufted, rather slender: 

 leaf -blades 1-2.5 dm. long, 26 mm. wide, rough: panicle 12.5 dm. long, its 

 ascending branches 3.5-8 cm. long: spikelets about 2 mm. long, on appressed 

 pedicels. [Agrostis intermedia ' Scribn., not Balb.] M. Bather rare, in 

 woods. Quartzite. Sum. 



27. NOTHOHOLCUS Nash. Annual or perennial grasses, with usually 

 flat leaf-blades and terminal spike-like contracted or open often interrupted 

 panicles. Spikelets crowded, 2 -flowered, the lower flower perfect, the upper 

 one staminate, the rachilla articulated below the empty scales. Scales 4, the 

 2 outer empty, keeled, the first 1-nerved, acute, the second broader, 3 -nerved, 

 acute or short -awned, the third and fourth scales shorter than the second, mem- 

 branous, at length rigid, enclosing flowers, the former awnless, the latter bear- 

 ing a slender dorsal awn which is often hooked when dry; palet narrow, 2- 

 keeled. Stamens 3, styles distinct. Stigmas plumose. 



