DIMORPHIC BRANCHES OF THE COTTON PLANT. 



27 



form. The analogy with the cluster habit of Upland varieties is 

 often very strong, and in these also the tendency to abortion of the 

 flower buds is often very great. Under favorable conditions cluster 

 varieties of Upland cotton are sometimes extremely productive, but 

 if unfavorable conditions supervene they are liable to Avholesale 

 abortion of the flower buds or the young bolls. The very strong 

 tendency to fruitfulness defeats itself. The plant is under too 

 great a strain of production and suffers the more acutely if condi- 

 tions become unfavorable. 



RELATION OF DIMORPHIC BRANCHES TO ACCLIMATIZATION. 



The recognition of the different behavior of the two forms of 

 branches is an essential step in the scientific study of many of the 

 problems of cotton 

 culture. One of the 

 most striking illus- 

 trations of the sig- 

 nificance of the di- 

 morphism of the 

 branches has been 

 shown in the study 

 of acclimatization. 

 Central American 

 varieties of cotton 

 that grew under 

 their native condi- 

 tions as low, short- 

 stalked plants with 

 few limbs and nu- 

 merous horizontal, 

 fertile branches 

 (fig. 1) showed in 



'J' g X a S a complete ^^^- -■ — Diagram of a cotton plant with numerous vegetative 

 „ , . „ brandies and no fruitfng brandies. 



change of habits or 



growth, becoming large, densely leafy bushes, with many strong, 

 sterile limbs, but with very few fruiting branches or none at all. 

 (Compare figs. 1 and 2.) 



If the change had affected only the size of the plants, it could have 

 been looked upon as a direct result of a rich soil or more favorable 

 conditions of growth, but the complete imlikeness of the Texas plants 

 to their Central x\merican parents showed that other factors were 

 involved. It was possible to raise large-sized plants Avhich still re- 

 tained the normal form and fertility of the type. The abnormal be- 

 havior of the plants was found to arise largely from the fact that 

 sterile limbs were substituted for the normal fruiting branches. 



198 



