122 



THE TRUE GRASSES. 



meal, is used as a mildly stimulating drink (hence the 

 officinal Avence fructus excorticatus}. It is also raised for 

 green fodder. There are two principal races : Panicled 

 oats, with expanded, and " Banner oats" (A. orientalis 

 Schreb.), with contracted, one-sided panicles. Each of 

 these is divided into the chaffy and naked-fruited varie- 

 ties, and the first, according to the color of the flower- 

 ing glumes, into white, yellow, gray, brown, and black 

 oats. In the naked oats (A. mida L.) the rachilla is pro- 



Fio. 63. Arena sativa L. (After Nees, Gen. Germ., I. 48.) 



longed and bears 4^6 flowers which project beyond the 

 empty glumes ; the flowering glumes are thiu-mem- 

 branaceous and allow the fruit to fallout. The "wild 

 oat" (A. fatua L.) is often very troublesome as a field 

 weed in crops, especially in Southern Europe. The 

 " Hairy oats" (A. strigosa Schreb.) and the " Short oats" 

 (A. brevis Both.) are distinguished from A. sativa by 

 the pedicellate lower flower and the usually two-awned 

 spikelets ; in the first the flowering glume is drawn out 



