112 CLASSIFICATION ACCORDING TO [CH. 



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

 varieties have to be distinguished. 



©0 Awns hair-like and dorsal on the palece. 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 florescence, or even 



pendent or drooping. 



* Spikelets awnless. 



+ A small aquatic grass with prostrate habit and 

 two-flowered spikelets with broad truncate 

 glumes and palese. 



Catabrosa aquatica, Beauv. (Fig. 4). 



The two-flowered spikelets distinguish it at once from Olyceria 

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

 small stature. Poa trivialis may have two flowers, but it is an 

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

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



tt Spikelets with at least three or four, but usually 

 more flowers. 



© A perennial field-grass xuith few large, 

 compressed, bluntly triangular or ovate 

 spikelets, dangling at the end of capil- 

 lary branchlets ; luith membranous, 

 loosely imbricated, concave and in- 

 flated palece and glumes, and 6 — 8 



flowers. 



Briza media, L. 



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



