CITRUS CULTURE IN CALIFORNIA — POLLINATION. 39 



to the two areas, the difierence in the habits of tree growth and 

 fruitfulness would be in part accounted for. If plants of known 

 purity of strain were exchanged by the two sections, Florida 

 and California, consisting of well-developed buds, on both the 

 sour and sweet stocks, and planted in average climatic con- 

 ditions in the two areas, should show a tendency to change 

 their habits of growth and fruitfulness, then climatic conditions 

 would be considered a cause sufficient for these effects and the 

 question of type inheritance be answered. Buds from the tree 

 at Washington distributed to the two sections and treated as 

 those exchanged by the two producing areas would further 

 simplify the solution of inherent qualities. 



Navel Unfruitfidness. — The orange-growers of Florida observed 

 the un fruitfulness of the Navel, in that State, early in its history. 

 This seemed to show itself in the young trees as well as in the 

 older orchards. The absence of pollen was noticed, and its 

 unfruitf ulness was attributed to this unsexed development of the 

 navel bloom. Professor Webber, of the United States Sub-Labo- 

 ratory, was led to believe that the Navel in California produced an 

 abundance of well-developed pollen, which was the cause of its 

 fruiting in this State. Professor Cook observed, some time since, 

 the absence of pollen in the Navel bloom in California. This dis- 

 covery established the normal unsexed quality of the Navel, in 

 both the great areas of Florida and California. The staminate, 

 or male, impulse is aborted and fails to produce developed pol- 

 len grains, or if it occasionally appears, is a lingering impulse 

 belonging to an incidental floral leaf. The impulse still exists 

 to produce a weakened staminal bud development. As this 

 development is arrested in the stamens and is only feebly 

 present in the bud, just sufficient to cause the growth of the 

 floral whorl bearing an anther without pollen, it would seem 

 as though the staminal impulse was a quality pertaining to 

 the root and in nowise dependent on the vegetative processes 

 of the leaf, and in the Navel it is as though nature had almost 

 withdrawn this force from the Navel tree and dissipated it in a 

 vigorous root growth. 



When it was known that the Navel was not self-pollinated, 

 it was affirmed that it was fruitful from the action of pollen 

 from other varieties planted in close proximity. The proof of 

 this was asked by Professor Webber and the question was sub- 

 mitted to Mr. E. W. Holmes and Mr. J. H. Reed of Riverside, 



