MORPHOLOGY OF COTTON BRANCHES. 15 



and this is especially likely to occur on the shortened fruiting branches 

 of small plants or at the end of the season when growth has nearly 

 ceased. In connection with the bractlike leaves of abnormally 

 shortened fruiting branches both the axillary and the terminal buds 

 are sometimes completely suppressed, as in the axils of the bracts of 

 normal involucres. 



TRANSFORMATION OF FRUITING BRANCHES INTO VEGETATIVE 



BRANCHES. 



Even on normal fruiting branches the pedicels of the floral buds 

 are not turned aside far enough to bring the successive joints of the 

 branches entirely into line, which accounts for the characteristic zig- 

 zag form of the fruiting branches, but when the floral buds are aborted 

 at a very early stage the branches are able to grow straight, like the 

 vegetative branches. Such transformed branches may show the scars 

 of aborted floral buds on a few of the lower joints, while the upper 

 joints are without scars and are as straight and upright as normal 

 vegetative branches. This is one of the ways in which fruiting 

 branches are transformed into vegetative branches, but such cases of 

 transformation during the growth of the branch are seldom found. 

 The transformations usually occur at earlier stages of growth, before 

 the formation of any floral buds, even on the basal joints. On nor- 

 mal fruiting branches the basal internode is longer than the others, 

 whereas vegetative branches often have short internodes at the base; 

 but some branches are intermediate in this respect, as well as in 

 other characters. 



Individual plants with branches of intermediate form have been 

 found in unacclimatized stocks of Kekchi and other imported types 

 of cotton. Though behaving as vegetative branches in other re- 

 spects, an abortive floral bud appears at each node throughout the 

 season. On some plants all the buds are shed while still very minute, 

 while on other plants the buds reach more advanced stages of devel- 

 opment. The closer the approach of the plants to normal fertility 

 the more zigzag the branches become. The occurrence of s,uch 

 transformations and in such various degrees does not indicate that 

 the two forms of branches are so fundamentally different as the 

 sympodial theory would imply. 



SUCCESSIVE GROWTH OF INTERNODES OF VEGETATIVE SHOOTS. 



That the zigzag form of the fruiting branches may be due to the 

 accelerated growth of the floral buds is also indicated by a similar 

 tendency in rapidly developing terminal shoots of main stalks or 

 vegetative branches, especially on large luxuriant plants. Here the 

 joints also appear somewhat zigzag at first, apparently because the 



[Cir. 109] 



