178 



THE FORAGE AND FIBER CROPS IN AMERICA 



visitation of insects is not recognized as a factor in the abun- 

 dance of seed. As the pistil grows into a pod it becomes a 

 spiral legume with two to four turns and is many-seeded. 



200. Seed. Alfalfa seeds are distinguished from seeds of 



closely related plants some- 

 what by their color, size, 

 and shape, although the 

 shape is quite variable, 

 owing to the occurrence of 

 several seeds in the spirally- 

 twisted seed pod. Viewed 

 laterally, they vary from 

 nearly oval in the smaller 

 specimens to distinctly kid- 

 ney-shaped in the larger 

 ones. The radicle (caulicle) 

 is half, sometimes a little 

 more than half, the length 

 of the seed; it is distinct, 

 but not prominent. The tip 

 of the caulicle does not 

 Alfalfa showing clusters of seed pods, a Single usually pro j e ct, and this 

 pod enlarged 



chiefly in the kidney-shaped 



specimens. The larger seeds especially are curved, and even 

 in some instances spirally-twisted. The color of the in- 

 dividual seed is uniform, except for the darker markings about 

 the scar and a light stripe which may occur along the raphe. 

 Alfalfa seed may be distinguished from red clover seed by its 

 uniform light olive-green color as contrasted with the purple 

 and yellow of the latter. Alfalfa seeds are usually 0.08 to 0.12 

 inch long, and 0.05 to 0.07 inch wide. The number of 

 seeds a pound may vary from less than 200,000 to more than 

 240,000; perhaps 225,000 would be a fair average. Sixty pounds 

 are sold for a bushel. 



