130 BOTANY OF CROP PLANTS 



Classification of Oats. — The common oat varieties in the 

 United States fall into three species: Avena sativa, A. 

 orientalis, and A. nuda. The latter two are sometimes 

 given as varieties of A . sativa. 



Avena sativa (panicle oats). — The common oats belong 

 to this species. In these, the panicles are spreading in all 

 directions (Fig. 45). A considerable number of forms are 

 recognized. Four main types, based upon character of 

 panicle, were given on page 125. As to color of grain, there 

 are white, yellow, gray (winter oats), brown and black sorts. 

 Some are bearded and some are beardless. 



Avena orientalis (banner, side, mane, or Tatarian oats) . — 

 The panicles of these species have erect branches which are 

 close to the main axis (Fig. 45). The inflorescence is one- 

 sided, which character has suggested the common names 

 ascribed to it. There are beardless-white, bearded-white, 

 beardless-yellow, beardless-brown, and bearded-brown 

 varieties. 



Avena nuda (naked or hull-less oats). — The grains of this 

 oat fall from the hull when threshed. It may be either a 

 spreading or side type. 



Other Cultivated Oats. — In addition to the three common 

 species of oats given above, the following species are recog- 

 nized and cultivated in various parts of the Old World: 

 Avena strigosa (rough oats), A. brevis (short oats), A- byzan- 

 tina (Mediterranean oats) and A . abyssinica (Abyssinian oats) . 



Avena fatua ("wild oats"). — The so-called "wild oat" is 

 often found in oat fields, and the "seed" may frequently occur 

 as an impurity in farm seed. The plant has slender stems, 

 which are long, and hence it usually stands above the culti- 

 vated oats. It has three flowers to a spikelet, and the awns 

 on the lemmas are strongly bent (Fig. 47), thus differing 

 from common oats. Again, it is distinguished from the 



