26 POACEAE. 



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

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

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

 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 

 i 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. alha. 

 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. 

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



Branches of the panicle capillary, elongate, commonly 



dividing above the middle. 

 Branches of the panicle not elongate, dividing at the 

 middle or below it. 



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

 long, 2-^ 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. — Eed-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 hispidulous on the keel. — 

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

 GEASS. ■ 'f 



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. scabra 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, 2-6 mm. wide, rough: panicle 1-2.5 dm. long, its 

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

 pedicels. [Agrostis intermedia Scribn., not Balb.] — M. Eather 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. 



