DIMORPHIC BRANCHES OF THE COTTON PLANT. 17 



In types of cotton that have a normal development of branches an 

 axillary bud yields only a sterile vegetative branch or limb. From 

 extra-axillary buds three things may come: (1) Flowers, (2) fertile 

 branches bearing a series of flower buds, one at each node, and (3) 

 extra-axillary limbs having the position of fertile branches but 

 sharinff the form and function of the axillarv limbs. 



VARIOUS FORMS OF FRUITING BRANCHES. 



As the fruiting branches represent a specialized feature of the cot- 

 ton plant, it is not surprising that different stages of specialization 

 are found in the fruiting branches of the various species and varie- 

 ties of cotton. Though the general distinctions between the vegeta- 

 tive limbs and the fertile branches apply to all forms of cotton thus 

 far examined, definite differences often appear between the fruiting 

 branches of different varieties and even among the individual mem- 

 bers of the same variet}'; and since these differences in the methods 

 of producing the fruit are of direct agricultural importance, it is 

 worth while to understand them in detail. 



In a general botanical sense it might be said that the fruiting 

 branches of all kinds are intermediate between the vegetative limbs 

 and the flowers, for botanists consider that each flower of a plant 

 represents a shortened branch. The range of specialization of fertile 

 branches lies, therefore, between the limb and the flower. The fer- 

 tile branches of some cottons are long and leafy, much like the vege- 

 tative limbs, while in others they may be so much shortened as to 

 appear merely a part of the flower stalk. In the great majority of 

 cases the fertile branches are definitely unlike either of the extremes, 

 but the range of forms is completely covered if the whole series is 

 considered. 



A comparison of the branches of the Egyptian cotton with those 

 of the Kekchi cotton or with our United States Upland varieties may 

 serve as an illustration of the different degrees of specialization 

 found in the branches in different types of cotton. In the Egy]:>tian 

 cotton the basal joints of the fruiting branches are longer than in the 

 Upland, while on the vegetative branches the basal joints are shorter 

 than on the corresponding branches of the Upland. In other words, 

 the differences between the basal joints of the two kinds of branches 

 are much greater in the Egyptian cotton than in the Upland series. 

 The tendency for the basal joint of the fruiting branches to be longer 

 than the others is very general, and likewise for the basal joints of 

 vegetative branches to be shorter, liut in the Egyptian cotton the con- 

 trast is more accentuated than usual. 



58S.S4°— Bui. 19N— 11 2 



