COTTON STRUCTURE 259 



are usually four or five divisions of each boll ; the content 

 of each division is called a lock. While upland American 

 cottons, both long- and short-staple, have usually four or 

 five locks, a boll of Sea Island cotton contains only three 

 or four. 



In tests made at the Alabama Experiment Station, 

 bolls with five locks afforded a larger yield of seed cotton 

 to the boll than did bolls having only four locks. 



The number of bolls varies somewhat with different 

 varieties, but is chiefly dependent upon conditions of fer- 

 tility, rainfall, and climate. The number may vary be- 

 tween a few and several hundred on a single plant. A 

 field averaging 50 mature bolls per plant usually makes 

 considerably more than a bale of cotton (500 pounds of 

 lint) per acre. Cotton plants of medium size, 3 to 5 feet 

 high, are apt to be more heavily fruited in proportion to 

 size than very large plants. Short internodes, or spaces 

 between branches, are favorable to productiveness. An 

 ideal cotton plant should have a number of nearly hori- 

 zontal fruiting limbs, beginning near the ground, and 

 continuing to arise at each node until considerably above 

 the middle of the plant. Each fruiting limb on the lower 

 part of productive plants should mature at least four 

 bolls. 



Cotton bolls of the Sea Island varieties are usually less than 

 one inch in diameter, and of slender, tapering shape. Bolls of 

 American upland cotton vary greatly in size and shape according 

 to variety, and the character of soil and season. The diameter 

 usually varies between 1J and 2 inches, and in most cases the 

 bolls are considerably longer than thick. Rich land and high 

 fertilization, together with abundance of moisture* tend to in- 

 crease the size of bolls. 



