Testing Farm Seeds. 



355 



slender spirally coiled, greenish embryo; common in alfalfa seed from the 

 Western States and in flaxseed; doubtless occasionally introduced in seed from 

 Russia. As an impurity of alfalfa seed it strongly suggests Western States 

 production. 



The seeds of corn cockle (fig. 17, i) are black or brown, angular, and cov- 

 ered with fine spiny tubercles; common in seed of cereals, millets, vetches and 

 flax from all sources. 



^^Sjipji*- 



m 



.^^^ 



Fig. 17.— Noxious weed seeds found in farm seeds (No. 1) : a. Sand bur; b, wild' 

 oat ; c, chess ; d, darnel ; e, quack-grass ; f, dock ; g, black bindweed : h, Russian 

 tni.-^tie ; i, corn cockle; j, white campion; k, bladder campion; I, night-flowering- 

 catchfly; m, cow cockle; n, pennycress ; o, field peppergrass ; p, large-fruited 

 false flax; q. small-fruited false flax; r, ball mustard; s, black mustard; t, 

 English charlock. (Enlarged and natural size.) 



White campion seeds (fig. 17, j) are mostly light gray, the surface 

 finely tubercled; the light color distinguishing this kind from the next two; 



