112 CLASSIFICATION ACCORDING TO [CH. 



Some forms of F. ovina are viviparous (see p. 134), and several 

 varieties have to be distinguished. 



Awns hair-like and dorsal on the paleoe. Flowers 

 two in each spikelet. Annual, six inches or less 

 in height. 



Aira prcecox, L. 



The rare A. canescens, L. also comes here: its awn is jointed and 

 with a minute tuft of hairs about the middle. 



(ii) Panicle lax and open, the fine hair-like branches 

 spreading widely during florescetice, or even 

 pendent or drooping. 

 * Spikelets aAvnless. 



+ A small aquatic grass with prostrate habit and 

 two-flowered spikelets with broad truncate 

 glumes and paleae. 



Catahrosa aquatica, Beau v. (Fig. 4). 



The two-flowered spikelets distinguish it at once from Glyceria 

 aquatica, to say nothing of its softer and smoother texture and 

 small stature. Poa trivialis may have two flow^ers, but it is an 

 erect meadow-grass, with keeled and pointed glumes and palese. 

 Aira and Agrostis are awned, or differ entirely in habit. 



t+ Spikelets with at least three or four, but usually 

 more flowers. 



© A perennial field-grass ivith few large, 

 compressed, bluntly triangular or ovate 

 spikelets, dangling at the end of capil- 

 lary branchlets ; luith membranous, 

 loosely imbricated, concave and in- 

 flated paleoe and glumes, and 6 — 8 



flowers, 



Briza media, L. 



The much rarer B. minor, L. is an annual and smaller. 



