PINEAPPLE GROWING'IN PORTO RICO. 



STRUCTURE OF THE PINEAPPLE PLANT. 



The pineapple plant consists of a short stem covered with leaves, 

 arranged in whorls, and supported by the roots, which are directly 

 attached. 



ROOT. 



The roots are fine and branched or in single strands of as much as 

 one-eighth of an inch in diameter, according to the conditions under 

 which they are formed. In water cultures or in mellow soil of a 

 uniform moisture the roots develop in fine strands which branch and 

 reach out like the roots of other similar plants. In heavy soils or 

 in extremely dry soils the roots are more or less coarse and usually 

 not much branched ; such roots may attain considerable length, how- 

 ever, and often wind around the stem of the plant instead of spread- 

 ing horizontally in the soil. This is especially so with old plants 

 which have produced several crops of suckers and to some extent 

 with large suckers remaining on the mother plant, although these 

 roots, while they are usually unbranchecl, will be found to develop 

 in the leaf axils of the mother plant. These roots are feeding roots; 

 if a sucker is planted in the soil immediately after removing from 

 the mother plant, the roots will continue to develop, whereas the 

 fine-branched roots developed in the soil often die on removing the 

 plant. Therefore, there is not much gained in transplanting old 

 plants with well-developed root systems. (See PI. VI, fig. 1.) 



LEAF. 



The leaf of the pineapple plant is in some varieties nearly 

 smooth, while in others the margins are covered with spines. The 

 spines were undoubtedly intended by nature to be a protection against 

 enemies, but in cultivated fields the only enemy from which they 

 could protect the fruit is the rat, and it always seems able to get its 

 share of the best pines. All other factors being equal, the spineless 

 variety is much preferable to those with spines, and considerable 

 progress has been made by the United States Department of Agri- 

 culture in eliminating these by crossing the spineless variety with 

 71070— Bull. 8— 09 2 (7) 



