graminejTC. 1001 



XXXV. POA. POA. 



Spikelets several-flowered (rarely only 2- flowered), awnless, nume- 

 rous, in a spreading or compact panicle. Outer glumes rather unequal, 

 usually keeled. Flowering glumes obtuse or pointed, but not awned, 

 scarious at the top, either keeled from the base or at the top only, or 

 rounded to the top without any prominent keel. 



A large genus, widely spread over all parts of the world. Although 

 in many respects a natural one, its characters and limits are far from 

 precise. It differs from Fescue only in its shorter glumes, without 

 awns or decided points, and some species have been placed alternately 

 in the one or the other genus. The first seven species are frequently 

 separated, and formed into one, two, or more genera, characterized by 

 minute differences in the nerves of the glumes or in the shape of the 

 minute floral scales, or of the seed ; and on the other hand, Catabrose, 

 Molinia, Triodia, Coclc's-foot, and Kceleria, although universally ad- 

 mitted, are distinguished by characters of very little more value. In 

 the present state of our acquaintance with the most practical principles 

 of classification in Grasses, the limits of Foa, as retained in the British 

 Flora, appear to be the most natural. 



Tall, aquatic plants. Spikelets not much flattened. Flower- 

 ing glumes rounded on the back, with prominent veins, 

 but not distinctly keeled. 

 Panicle large and spreading. Spikelets 3 to 5 lines long 1. Reed P. 

 Panicle long and narrow. Spikelets erect, 6 lines to an 



inch long 2. Floating P. 



Plants not aquatic. 



Panicle one-sided and stiff. Flowering glumes rounded 

 on the back, at least at the base. 

 Panicle rather loose, 4 to 6 inches long. Glumes al- 

 most nerveless. Stock perennial. 

 Stem creeping at the base. Flowering glumes 

 about 1^ lines long. 



Leaf-sheaths much flattered . 9. Flattened P. 



Leaf-sheaths not flattened 3. Sea P. 



Stems tufted. Flowering glumes about 1 line long 4. Reflexed P. 

 Panicle compact, seldom 3 inches long. Spikelets 

 croivded. Root annual. 

 Spikelets about 3- or 4-flowered. Flowering glumes 



strongly nerved 5. Procumbent P. 



Spikelets 6- or more flowered. Flowering glumes 



faintly nerved 6. Hard P. 



Panicle reduced to a single spike, with the lower spike- 

 lets occasionally clustered. Root annual ... 7. Darnel P. 

 Panicle scarcely one-sided, the branches and pedicels 

 VOL. TT. 2 Q 



