Aira.} GRAMINEJB. 



}- -j- Calyx two- or rarely three-flowered. 



8. CATABROSA. Beauv. Whorl-grass. 



Panicle spreading. Calyx of two valves, membranaceous, very 

 obtuse, much shorter than the spikelets, two or three-flowered, 

 often with a fourth imperfect floret. Calyx two-valved, cori- 

 aceous, membranous only at the extremity, ribbed, truncated, 

 awnless, erose, nearly equal. Named from Katappiaats, a 

 gnawing, from the erose extremity of the glumes. 



Triandria. Digynia. 



1. C. aquatica, Beauv. Water Wliorl-grass. Panicle with 

 whorled patent branches ; leaves broadly linear, obtuse. Br. Fl. 

 ed. 3. p. 39. Aira aquatica, Linn. E. Bot. t. 1557. E. Fl. v. i. 

 p. 101. 



Muddy ditches and watery places. Fl. May, June. 1 . This, as 

 Doctor Hooker remarks, is very different in habit and generic charac- 

 ter from Aira. 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. Culm or rather caudex of the root 

 very long, branched, floating, jointed, sending from the joints fibrous 

 radicles below, and culms above, a foot or more long, stout, with short 

 broad leaves. Calyx scarcely nerved, thin and membranous, broadly 

 oval, obtuse. Corolla of a thick texture, brownish-green, white and 

 diaphanous at the blunted extremity. 



9. AIRA. Linn. Hair-grass. 



Calyx of two valves, unequal, containing two perfect flowers. 

 Corolla 2-valved, membranaceous and thin ; the outer one 

 awned (rarely awnless) near the base. Fruit free. Named 

 from aipw, to destroy. This name was anciently applied to Lo- 

 lium temulentum, ( bearded Darnel, J on account of its injurious 

 effects: and now to the present genus, though having little 

 in common with it. Triandria. Digynia. 



4c Corolla awnless. Panicle spiked. Kreleria, Per soon. 

 Airochloa, Link, Lindl. 



1. A. cristata, Linn. Crested Hair-grass. Panicle spiked, 

 smoothish ; leaves hairy. Br. Fl. ed. 3. p. 39. E. Fl. v. i. p. 101. 

 E. Bot. t. 648. Po, Linn. 



Dry pastures, especially near the sea, frequent. Fl. June, July. 

 1. Six to eight inches high. Leaves linear, short, glaucous. Spike 

 shining, ovato-lanceolate. Glumes of the calyx acute, lanceolate, 

 compressed, glabrous, and downy and a little rough at the keel. Inner 

 valves of the corolla rough, white, delicate, reticulated, bifid, with two 

 longitudinal folds. 



