ELEVENTH ANNUAL YEAR BOOK— PART XI 761 



end of the scar. Some seeds of spring vetch are large, compressed, and 

 somewhat angular; others are nearly spherical and smaller. The surface 

 is black, brown, gray, or mottled. In one variety, a common impurity 

 of winter vetch seed, the seeds are spherical, jet-black, and about the size 

 of the smaller winter vetch seeds. Only careful examination under a 

 magnifier discloses their darker color and characteristic scar in which, 

 however, the margins of the scar slit are black. In testing seed of 

 winter vetch the seeds of this variety of spring vetch should be sought 

 especially. Seeds of other varieties of spring vetch are usually disting- 

 uishable from winter vetch seeds by their different form or color. 



Various weed seeds, mostly of the class appearing in seed of millets 

 and cereal grains, are sometimes present in poorly cleaned vetch seed. 

 The seed of a wild species of vetch (Vicia Mrsuta (L.) Koch,) is a com- 

 mon impurity of cultivated vetch seed. 



Vetch seed should show nearly 100 per cent purity. The viability 

 of commercial seed is variable and is strongly influenced by the hard 

 seed, especially in the case of winter vetch in which the hard seed may 

 amount to 30 per cent or more. In spring vetch the hard seed usually 

 varies between 5 and 15 per cent. The sprouting of the hard seed is 

 hastened in the test by cutting through the seed coat with aj knife 

 blade, thus admitting moisture. The coat should not be cut in the vicin- 

 ity of the seed scar lest the embryo be injured. 



The germinable seed in high-grade lots of commercial winter vetch 

 seed, together with the variable quantity of hard seed, ranges from 

 95 to 98 per cent. Some lots germinate between the second and sixth 

 days; others during the second week of the test. 



In spring vetch viability of 95 to 98 per cent is less commonly reduced 

 by the hard seed. Sprouting takes place chiefly between the third and 

 fifth days. 



TESTING SEED CORN. 



The testing of seed corn so far as it corresponds to the tests applied 

 to seed of other crops consists chiefly of the germination test, showing 

 how much of the seed will germinate and with what vigor. Assuming 

 that the corn to be used for seed is in the ear and has been selected with 

 reference to variety and in conformity with the recognized type of ear 

 and of kernel best adapted for crop production, it remains to test its 

 viability. 



The two types of germinator adapted for this work have already been 

 referred to. After removing sufficient of the butt and tip kernels 

 of the ear to leave on the cob kernels of uniform size, 6 kernels 

 are removed for test. Of these, 2 are taken from near the butt, 2 from 

 the middle, and 2 from near the tip. Each pair of kernels should be 

 taken from opposite rows, these rows being one-third of the circumfer- 

 ence of the ear apart. In this way fairly representative kernels of the 

 ear are chosen. The kernels are placed side by side, germ side uppermost, 

 in the marked squares of the germinator which are numbered serially, 

 the ears furnishing the kernels for the squares being numbered corres- 



