516 FORAGE PLANTS AND THEIR CULTURE 



or sometimes black. Gray pods always bear gray pubes- 

 cence, while the tawny pods have tawny pubescence. 

 Black pods may have either color as to pubescence. 



The variation in the seeds of the soybean is very great. 

 Some are nearly globose, others much flattened, but the 

 great majority are elliptical in outline, the thickness 

 less than the breadth. The largest seeded sorts contain 

 about 2000 seeds to the pound, while the smallest seeded 

 contain about 7000. The color of the testa shows the fol- 

 lowing range of colors : straw yellow, olive yellow, olive, 

 green, brown and black. In a very few varieties, the 

 testa may be bicolored. Among such combinations are 

 green or yellow with a saddle of black, and brown and 

 black in concentric bands. On heterozygote plants, the 

 seeds are often irregularly two-colored, but these do not 

 breed true. The embryo or germ may be either yellow 

 or green. It is green in all the green-seeded varieties and 

 in some of the black-seeded ones, in all others being 

 yellow. 



628. Description. The soybean is an annual, and 

 strictly determinate in growth; that is, the whole plant 

 reaches maturity as the pods ripen, and no further growth 

 takes place. ? Most of the cultivated varieties are erect 

 and branching, the main axis being well defined. With 

 few exceptions such varieties have decidedly stout stems. 

 In other sorts the stems and branches are somewhat 

 twining and weak, so that the plant is more or less procum- 

 bent. All intergrades between these types of growth 

 exist, some sorts being slender-stemmed with the branches 

 more or less twining. The height of the stem varies accord- 

 ing to the variety from six inches to six feet. In general, 

 the earliest varieties are the most dwarfed. 



All soybeans are hairy plants, no smooth variety being 



