VII] FLORAL CHARACTERS 117 



= Tall annual corn-weed, with large (18- 

 20 mm.) Iieavy, pendent, hairy spikelets on 

 the long slender stalks of the lax open 

 panicle. Leaves glabrous. 



A. fatua, L. 



This is the so-called Wild Oat, and the type of this group. 



= = Tufted perennials with spihelets more or less 

 erect on stiffer stalks, the panicle therefore 

 less open. 



z Panicle nearly simple ; spikelets silvery or 

 reddish, 12 — 15 mm. long. 



A. pratensis, L. 



zz Panicle branched but not very open; 

 spikelets glistening yellow and only 

 5 — 6 mm. long. 



A. flavescens, L. 



There is no other genus closely resembling Avena. The 

 superficial likeness of some Bromes disappears at once on exami- 

 nation. The spikelets of Aira are much smaller, and the leaves 

 quite different (see below and p. 47). 



0© Awns fiiie and hair-like and not con- 

 spicuously protruding from the spike- 

 lets; the latter small, 2 — 5 m,m. Flowers 



two in each spikelet. 



'Aira. 



= Coarse and tall tufted grass with flattened, 

 harsh, and conspicuously ribbed leaves: the 

 very short awns hardly protruding. 



A. ccBspitosa, L. 



No other grass can be confused with this if the very high ridges 

 of the leaves are observed (see p. 47). 



= = Small grasses with setaceous or very narrow 

 inrolled leaves. Aums slightly protruding. 



