102 TRIANDRIA— DIGYNIA. Aira. 



acute, flat, single -ribbed, with long, clasping, more or less downy 

 or hairy sheaths, and a very short, slightly fringed, stipula. The 

 edges of the leaves are rough and hairy, as Professor Schrader 

 rightly observes, in opposition to my former descriptions, but 

 this character varies in degree ; their upper surface is strongly 

 ribbed. Panicle lanceolate, dense, erect, many- flowered, from 

 1 to 4 or 5 inches long, compound and somewhat interrupted, 

 conspicuous for its shining silvery hue, mixed with pale purple 

 and green 5 the common stalk densely downy. Fl. crowded, 

 erect. Glumes all similar, compressed, finely pointed, with mem- 

 branous edges. Florets very rarely 3. 

 This species is a Festuca, except in the small number of florets. 



2. A. aquatica. Water Hair-grass. 



Panicle spreading. Florets awnless, even, obtuse, longer 

 than the calyx. Leaves flat. Stipula oblong. 



A. aquatica. Linn. Sp. PL 95. Witld. v. 1 . 376. Fl. Br. 84. Engl. 



Bot. v. 22. t. 1557. Curt. Lond.fasc. \.t.5. Knapp t. 29. Hook. 



Scot. 29. Schrad. Germ. v. 1 . 256. Host Gram. v. 2. 30. t. 41. 



Fl. Dan. #.381. Ehrh. Calam. 4. 

 Poa dulcis. Salisb. Pr. 20. 

 P. n. 1471. Hall. Hist. v. 2. 225. 

 Gramen paniculatum, aquaticum miliaceum. Vaill. Par. 89. 1. 17. 



G. miliaceum aquaticum. Rail Syn. 402. Scheuchz. Agr. 176. 



In ditches, pools, and the margins of rivers. 



Perennial. May, June. 



Root creeping, or floating, with long, white, shining fibres. Stems 

 floating, branched, leafy, smooth, very long, rising about 12 or 

 18 inches above the water. Leaves linear, bluntish, flat, flaccid, 

 partly floating, bright green, smooth, except at theedges. Sheaths 

 lax, slightly compressed, smooth, with a prominent, broad, rather 

 pointed, membranous stipula. Panicle erect, repeatedly branch- 

 ed, smooth j the branches unequal, aggregate, angular, many- 

 flowered. Calyx-valves not on a level, short, abrupt, notched, 

 ribbed at the lower part, purplish, smooth. Florets much longer, 

 one on a short stalk; their valves oblong, even, purplish, notched 

 at the end, strongly keeled, never awned. Anth. prominent, ob- 

 long, yellow. Styles and stigmas short. The flowers abound 

 with honey. When growing accidentally out of the water, this 

 grass sometimes assumes a very dwarf habit. In natural affinity 

 it comes near Poajluitans, distans, and maritima. 



## Corolla awned, hairy at the base, 



3. A. ccespitosa. Turfy Hair-grass. 



Panicle spreading. Florets about the length of the calyx, 



