34 POACEAE. 



Spikelets ovate or oblong, 8 mm. long or less. 



Flowering scales very broad, obscurely or at least not sharply nerved. 



1. P. canadensis. 

 Flowering scales narrow, sharply and distinctly 7-nerved. 



Panicle elongate, its branches erect or appressed. 2. P. Torreyana. 



Panicle not elongate, its branches usually spreading or 

 ascending, sometimes drooping. 

 Spikelets 3 mm. long or less : branches of the panicle 



often drooping. 3. P. nervata. 



Spikelets 4-6 mm. long : branches of the panicle as- 

 cending or spreading. 4. P. grandis. 

 Spikelets linear, 12 mm. long or more. 5. P. fluitans. 



1. P. canadensis (Michx.) Kuntze. Stems 6-10 dm. tall: leaf -blades 1.5-3.5 

 dm. long, 4-8 mm. vride: panicle 1.5-3 dm. long, open, the slender branchea 

 drooping: spikelets 5-12-flowered, 5-8 mm. long, the flowering scales broad, 

 3-4 mm. long, obtuse or abruptly pointed. — N. S. Rather rare, in swamps. — 

 Sandstones and shales, schists. — Sum. — Eattlesnake-grass. 



2. P. Torreyana (Spreng.) Merrill. Stems 6-9 dm. tall: leaf -blades 1.5-3 dm. 

 long, 3-6 mm. wide: panicle elongate, usually nodding at the summit, 1.5-3 

 dm. long: spikelets 3-4-flowered, 3-4 mm. long, the flowering scales about 2 mm. 

 long, obtuse or acutish. — N. Eare, in swamps. — Sandstones and shales. — 

 Sum. and fall. 



3. P. nervata (Willd.) Kuntze. Stems 3-9 dm. tall: leaf -blades 1.5-3 dm. 

 long, 4-10 mm. wide: panicle 7-20 cm. long, often purple, the branches spread- 

 ing, ascending, or often drooping: spikelets 3-7-flowered, 2-3 mm. long, the 

 flowering scales about 1.5 mm. long, obtuse or rounded. — Eather common, in 

 swamps and low woods. — Sum. — Fowl meadow-grass. 



4. P. grandis (S. Wats.) Nash. Stems 9-15 dm. tall: leaf -blades 2-3 dm. long 

 or more, 6-16 mm. wide: panicle 2^ dm. long, the lower branches 1-2 dm. long: 

 spikelets 4-7-flowered, 4-6 mm. long, the flowering scales about 2 mm. long. — 



5. Eare, in swamps. — Schists. — Sum. — Eeed meadow-grass. 



5, P. fluitans (L.) Kuntze. Stems 1-1.5 m, long: leaf -blades 1-3 dm. long or 

 more, 4—12 mm. wide, rough, often floating: panicle 2-4.5 dm. long, its branches 

 finally ascending: spikelets 7-13-flowered, 2-2.5 cm. long, the flowering scales 

 4-5 mm. long, thick, oblong, rounded or truncate at the erose apex, hispiduloua. 

 — N. S. Rare, in swamps. — Sandstones and shales, schists. — Sum. 



44. FESTUCA L. Usually perennial, rarely annual, tufted grasses, with 

 flat or convolute sometimes setaceous leaf -blades and contracted often spike- 

 like or open panicles which are sometimes nearly racemose. Spikelets 2-several- 

 flowered, the flowers perfect or the upper ones staminate, the rachilla articulated 

 between the flowers. Scales 4-several, membranous, the 2 lower empty, unequal, 

 acute, keeled, the flowering scales rounded on the back, at least below, acute 

 or rarely obtuse, usually more or less awned, occasionally awnless, the remaining 

 scales if any, empty; palet a little shorter than the scale, 2-keeled. Stamens 

 1-3. Styles very short, distinct, terminal or nearly so. Stigmas plumose. — 

 Fescue-grass. 



Plants annual : stamens 1 or 2. 1. P. octoflora. 



Plants perennial : stamens 3. 



Panicle open, its branches at maturity ascending or spreading : 

 spikelets usually less than 6-flowered. 

 Panicle branches elongate, spikelet-bearing toward the 



end. 2. F. nutans. 



Panicle branches not elongate, spikelet-bearing from at 



or below the middle. 3. p. Shortii. 



Panicle contracted, its branches erect or appressed : spikelets 



often 10-flowered. 4. p_ elatior 



