CITRUS CULTURE IN CALIFORNIA — POLLINATION. 35 



"sport" and give new or modified varieties, it is to the stami- 

 nate and pistillate modifications that we must look for the 

 primary changes in the fruit and tree habits of growth. 



The least modification impressed upon the pollen impulse, 

 and the receptivity of the ovarian cell, will change, modify, or 

 eliminate some habit of the tree, or quality of the fruit, in the 

 embryo and bud. 



It is apparent that in the bitter orange of the higaradia, the 

 male or staminal poiver is in the ascendancy. The whole tree, 

 in all its manifestations, is suffused by this power. It primar- 

 ily affects the cell of the leaf, the branch and root. It influ- 

 ences the vitality, the strength, and the compactness of the 

 protoplasmic unit in the pollen germ. It is manifested in the 

 heavy compact limb, the stout effective thorn, the resistant 

 and strong terminal root growth, the thick leaf, the pungent 

 oils, the bitter compounds of the rind and cells of the carpel, 

 and in the capacity to resist the elaboration of sugar from the 

 fruit acid, compelling the slow development of a strong germi- 

 native and generative seed. 



Modifications in the Pollen Impulse. — Either bj- nature or cul- 

 tivation the strength of the pollen impulse was changed. The 

 staminate or male power of the bitter orange was acted upon, 

 and its supremacy destroyed. When that was accomplished, 

 those qualities that nature used to protect the seed were either 

 without necessity or modified to the changed habits of the new 

 tree. As these changes were produced, the whole tree was 

 acted upon to adjust a correlated growth. The germ cells were 

 changed in their capacity to produce a constant type. The 

 vegetative functions were immediately increased, and those 

 parts of the tree impulse put forth a growth modifying those 

 protective growths built upon the defense and perpetuity of the 

 seed. As an immediate result of the loss in the pollen impulse, 

 the leaf increased in surface. The root cells were enlarged 

 and enabled to absorb liquids to meet an increase of leaf 

 evaporation. The whole tree acquired a greater heat range 

 and became more tropical. These modifications, of the micro- 

 scopic pollen cell in its constructive energy to maintain a per- 

 manent type, are seen in the habits of growth and fruit of the 

 sweet orange {Citrus aurantium) of our orchards. 



Citrus Aurantium. — This orange is in such marked contrast 

 from the bitter orange that eminent authorities have debated 



