SPECIES AND VARIETIES. 77 



(117) Aira. HAIR- GRASS. 



A. preecox : annual, tufted, 3-6 inches high ; panicle con- 

 tracted, ^-1 inch long. Dry gravelly ground. Fl. April, 

 May. 



(118) Poa. MEADOW-GRASS. 



* Rootstoclc tufted. 



P. annua : annual, stems spreading below, 3-] 2 inches 

 high; panicle loosely spreading, 1^-3 inches long; florets 

 not webbed. Meadows and cultivated ground everywhere. 

 Fl. all the year. 



P. bulbosa : stems swollen and fleshy or bulbous at the 

 base, 6 inches high ; panicle ovate or oblong, close, about an 

 inch long ; florets webbed at the base. Sandy sea shores. Fl. 

 April, May. 



P. trivialis : stems 12 feet high, and as well as the leaf- 

 sheaths roughish to the touch ; panicle spreading 3-6 inches 

 long ; spikelets ovate of 2-3 acute webbed florets. Meadows 

 and pastures, common. Fl. May and June. 



** HootstocTc creeping. 



P. pratensis : stems 1-2 feet high, and as well as the leaf- 

 sheaths smooth ; panicle spreading 2-3 inches long; spikelets 

 ovate or oblong, of 3-4 webbed florets. Meadows and pas- 

 tures, common. Fl. May and June. 



