IN THE FIELD 195 



in all our states. It grows on broken soil in all crops and 

 on stubble. Small grain, if in good condition, keeps it 

 down ; in corn and potatoes it has to be kept down by culti- 

 vation. Its name refers to the tawny yellow spikes or ears. 

 Two other species of foxtail are also common, both from 

 Europe. The cultivated millet also belongs to the foxtail 

 grasses. 



3. Wild Oats. 



This weed is most troublesome from Minnesota to Oregon 

 and California. The species here referred to is distinguished 

 from cultivated oats by its usually larger size, earlier and 

 irregular ripening. Each grain falls out as soon as it is 

 ripe, and the first and second floret are each provided with 

 a strong, twisted, and bent awn. The skin or glume enclosing 

 the grain is hairy below the middle, usually nearly black at 

 maturity, and harder and tougher than that of cultivated 

 oats. The grain itself is much lighter than the cultivated 

 varieties of white oats. Compare cultivated oats. 



It is most troublesome in oat crops, because it crowds out 

 the true oats and reduces the value of the threshed grain. 

 The stiff, twisting awns sometimes cause trouble by irritat- 

 ing the nostrils and mouths of animals. 



How to destroy it. If a field is not badly infested, it 

 may be pulled or cut by hand, before it matures. No oats 

 should be sown on such fields. 



For cleaning out badly infested fields, see Farmers' Bulletin, No. 28, 

 U. S. Department of Agriculture. 



29. The Common Milkweed, or Silkweed. Asdepias 

 Cornuti. 



MATERIAL : Plants at different stages of development, some show- 

 ing the perennial rootstock ; several flowers for each pupil ; several 

 dead butterflies, moths, bees, wasps, and other insects with pollen 

 masses attached to their feet ; pass the insects around when the fer- 



