36 TniANDniA — dioynia. [Aim. 



pid, branclilets patent, outer valve of cor. S-nerved, ligule oblong. 

 E. Bot. t. 1 189. E. Fl. V. i. p. 93. Schrad. Germ. p. 209 (descr. 

 excellent). — A. stolonifera, Linn, E. Bot. t. 1532. 



Pastures, roadsides, and in various oilier situations, abundant. Fl. 



July, August. If Plant stouter than the last, and generally taller. 



Culms ascending, often rooting at the base, and throwing out runners. 

 Panicle rather contracted, pale green or purplish, hranchlets patent. CuL- 

 glutnes like those in A. vuhjaris, as are those of the cor., but the outer 

 valve has 3 nerves and as many teeth, and the inner one is only faintly 

 2- or 3-nerved at the base, nearly entire and obtuse at the extremity. 

 In some there is a short awn at the liase of the outer valve of the cor., 

 this constitutes the A. compressa, Willd., and occasionally the flowers 

 are viviparous, which is the A. sylvntica, Linn. I believe all are now 

 agreed that the A. stolonifera of authors is the same as A. alba. The 

 famous Fiorin-grass of Dr Richardson and the Irish agriculturalists is 

 what I have called A. alba, as I ascertained by the aid of specimens 

 gathered in the company of Dr Richardson liimself. I know not of any 

 British awnless Afjrostides, which may not be reduced either io A. vul- 

 garis or A. alba. Tlie two species are indeed themselves very closely 

 allied. 



25. Catabrosa. Beauv. Whorl-grass. 



1. C. aqudtica, Beauv. {loater Whorl-grass) ; panicle with 

 whorled patent brandies, leaves broadly linear obtuse. — Aira 

 aquatica, Linn. E. Bot. t. 1557. 



Banks of rivers, and floating in pools of water. 2^/. May, June. 1^ . — 

 This is very different in habit and generic character from Aira, and from 

 any other grass I am acquainted with, Mertens unites it to the long- 

 spikeleted Poas, which now, according to Smith, form the genus Glyceria; 

 but it does not naturally combine with them. Root or caudex very long, 

 branched, floating, jointed, sending from the joints fibrous radicles below, 

 and culms above, a toot or more long, stout with short broad leaves. Cal. 

 scarcely nerved, thin and membranous, broadly oval, obtuse. Cor. of a 

 thick texture, brownish-green, white and diaphanous at the blunted ex- 

 tremity. Mr Wilson finds in the wet sand of the north shore at Liver- 

 pool, a var. not two inches high, each calyx containing in general but 

 one perfect flower. 



26. AfRA. Linn. Hair-grass. 



* Corolla mvnless. Panicle spiked. (Koeleria, Per^. Airochloa, 

 Li7ik, Lindl.) 



1. A.cristdfa, L. (crested Hair-grass) ; panicle spiked smooth- 

 isli, leaves hairy. E. Bot. t. 648. — Poa, Linn. 



Dry pastures ; most frequent in the north, and especially near the 

 sea. Fl. Jime, July. If 6 — 8 inches high. Leaves linear, short, glau- 

 cous. Spike shining, ovato-lanceolate. Glumes of the cal. acute or 

 slightly acuminate, lanceolate, compressed, glabrous or downy and a little 

 rough at the keel. Inner valves of the corolla rough, white, delicate, 

 reticulated, bifid, with two longitudinal folds. 



** Corolla awned. Panicle lax. 



2. A. ccespitosa, L. (turfy Hair-grass); panicle diffuse, branched 

 scabrous, florets liairy at the base rather longer than the cal., awn 



