38 



DIMOEPHIC BRANCHES IN TEOPICAL CROP PLANTS. 



«V-' 



lateral branches. It is the custom of planters in Jamaica, according 

 to Mr. G. N. Collins, of the Bureau of Plant Industry, to pull off the 

 uprights instead of cutting them, on the ground that this prevents 

 the growth of an}^ more uprights. It is easy to understand that 

 additional uprights may develop from buds of short basal joints of 

 uprights that have been cut otf, but this would not be the case with 

 uprights that are pulled out. An additional bud can be seen on 

 Plate IV, underneath the base of one of the new uprights that have 

 been forced by pruning. 



If the fertility of a plantation is to be maintained, resort must be 

 had to some form of pruning, in order to continue the formation of 



healthy new^ wood on which good fruit 



V , , can be borne. Old trees that are not 



\ \ ; / / pruned tend to produce slender branches, 



narrow leaves, and very small fruit. New 

 wood can be obtained by allowing new 

 uprights to develop or by preventing the 

 growth of the uprights and forcing the 

 laterals to branch. The use or the rejec- 

 tion of the uprights affords a fundamen- 

 tal distinction between the several differ- 

 ent systems of pruning coffee. 



The subject is one of too great extent 

 and complexity to be discussed in detail 

 here. Methods that may be thoroughly 

 justifiable and advantageous under the 

 conditions of one coffee-growing district 

 may be objectionable in another, or even 

 destructive, so greatly do the habits of the 

 plants differ under different conditions 

 of climate and soil. The practicability of 

 the different systems of pruning depends 

 also very largely upon the character and 

 cost of labor. In some countries the natives 

 show much aptitude for such work, but in others only the simplest sys- 

 tems can be applied ; the cost of skilled assistance would be prohibitive. 



DIMORPHIC BRAlSrCHES OF CACAO. 



The cacao tree bears two distinct kinds of branches, but these do 

 not correspoid directly to those of the rubber tree, the coffee, or the 

 cotton. The fruit-bearing function is not confined to either type 

 of branches. Both have vegetative functions, and both produce the 

 small leafless twigs that bear the flowers and fruits. Even the main 



Fig 7. — Diagram of a cacao tree 

 with three upright shoots 

 and three groups of whorl 

 branches. 



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