28 FARM WEEDS OF CANADA 



WILD OATS (Avena fatua L.) 



Other Latin names: Avena fatua L., var. glabrata Peter- 

 mann; Avena fatua L., var. glabrescens Cosson. 



Introduced from Europe. Annual, smooth, 2 to 4 feet 

 high, growing in erect tufts. Plant closely resembles some 

 varieties of cultivated oats. Panicle is compact when it appears 

 but quickly opens, spreading in all directions, 6 to 12 inches 

 long. 



The seeds (Plate 72, fig. 4) vary greatly in size and in colour; 

 they are brown or gray of different shades, sometimes yellowish- 

 white. They are similar to those of the common cultivated 

 varieties of oats, but generally slimmer, harder, of a horny 

 appearance, and show the following characteristics of differen- 

 tiation: 



1. The strong, twisted, right-angled awn, frequently broken 

 off by threshing. 



2. The stiff bristles surrounding the basal scar, which, 

 however, are not always present in threshed grain. 



3. The slanting horseshoe-shaped scar at the base of the 

 seed, which is sometimes broken off by the thresher or other 

 machine. 



4. The minute stalk (rachilla) which bears the second or 

 "bosom" grain, but which remains attached to the lower grain, 

 is larger and thicker. The free end is slanting, roughly triangular 

 and shows a marked depression. 



5. The abundance and roughness of the hairs covering the 

 kernel. 



Time of flowering : Uneven, commencing about the last of 

 June; some seeds ripe by the middle of July. 



Propagation: By seeds only. Plants cut off when in flower 

 throw up secondary flowering stems very quickly. 



Occurrence: Widely distributed throughout Canada; most 

 abundant and troublesome where cereal crops predominate. 



