CEREAL PESTS WEEDS 449 



nels, resembling those of common black oats, but not so 

 plump and having a more pronounced horseshoe-shaped 

 scar and a long stiff awn and densely hairy base ; (2) a 

 white form, the kernel of which resembles that of the 

 form just described except that it is creamy white, like 

 ordinary white oats ; (3) a hairy form which differs from 

 the others in having a kernel densely hairy almost to the 

 tip. There are other hybrid forms, having kernels of 

 varying shades of color, but usually gray. 



The first step in eradication is to sow clean seed. If 

 the field is already infested, the grain crop should be fol- 

 lowed with one or more cultivated crops. Growing winter 

 cereals in place of spring cereals will permit harvesting 

 to be done before the wild oats mature. Disking at once 

 after harvest will induce germination of many of the 

 mature seeds remaining, and later plowing will kill the 

 plants. Some seeds, however, may lie in the ground 

 20 months or longer before germinating. A rotation 

 including at least 1 or better 2 intertilled crops should be 

 practiced. 



488. False wild oats are occasionally found in culti- 

 vated varieties, which usually possess the horseshoe- 

 shaped scar, or " sucker mouth," at the base of the lemma, 

 and sometimes have the twisted awn. They may usually 

 be distinguished from, the true wild oats by their greater 

 plumpness and close general resemblance to the kernels 

 of the variety in which they appear. They are also 

 usually less hairy than the wild oat. 



In Canada, Griddle (1912, pp. 8-11) has identified 

 five distinct types of false wild oats, similar to the varieties 

 in which they are found, as follows : (1) the Banner 

 type ; (2) the Newmarket or Abundance type ; (3) the 

 Old Island Black type ; (4) a black oat type ; and (5) the 

 2o 



