DIMORPHIC BRANCHES OF THE COTTON PLANT. 21 



important that the plants shall be able to produce enough flower 

 buds to take advantage of all opportunities for the setting of a large 

 crop. The tendency of the Egyptian cotton to grow larger vegeta- 

 ti^e branches and smaller fruiting branches than the Upland cotton 

 is responsible for differences in yield and earliness between the two 

 types. 



In Egypt and in the cooler parts of the United States the Egyptian 

 cotton produces small, early plants with much the same habit of 

 growth as the Upland cotton. The more fertile soils and the greater 

 heat of the spring months in the Southwestern States induce a much 

 more luxuriant growth, especially in the Egyptian cotton. The plants 

 not only shoot up to a very large size, but put forth many vegetative 

 branches from the base of the stalk before any fertile branches are 

 formed. 



INTERMEDIATES BETWEEN FERTILE BRANCHES AND FLOWERS. 



Farther toward the top of the plants another intermediate condi- 

 tion of the branches is frequenth^ found, especially in the Egyptian 

 cotton. The fertile branches become abnormal by approximation to 

 flower buds. The leaf bud that would continue the growth of a nor- 

 mal fruiting branch either becomes abortive or appears to be 

 directly transformed into a flower bud. A further evidence of the 

 abnormality of these branches is found in the fact that their leaves 

 are usuallv different from those of normal fruiting branches and 

 tend to take on the form of the floral bracts. The first and most 

 frequent manifestations of this tendency are found in the shortening 

 of the petiole or stem of the leaf and the enlargement of the stipules — 

 the small, pointed, leaf-like structures at the base of the petiole. 

 (See PI. I.) 



On the normal fruiting branches the stipules are always shorter 

 than those of the main stem or vegetative limbs, remaining narrow 

 and pointed; but on the abnormal, shortened, fruiting branches one 

 or both of the stipules become broadened and thickened as in the 

 formation of the floral bracts. In Egyptian cotton it is easy to find 

 all these abnormal fruiting branches completing a series of grada- 

 tions between normal leaves or completely modified floral bracts. 

 That the abnormality of the branches involves in this case the break- 

 ing down of the distinctions between the internodes of normal fruit- 

 ing branches and those of the more specialized floral organs is also 

 shown by the fact that leaf -like bracts are often found as well as 

 bractlike leaves, and that supernumerary petals, divided stamina! 

 tubes, and abnormal pistils are of frequent occurrence on plants that 

 show abnormal intermediate foi-ms of branches. 



198 



