BUREAU OF PLANT INDUSTRY. 331 



strikingly shown by the past season's work. The trees that gave 

 the largest yields of fruit in 1910 produced the largest yields in 

 1911 without exception. The trees bearing the smallest yields of 

 fruit in 1910 produced the smallest yields in 1911. The most pro- 

 ductive trees bore the best and most uniform fruit, i. e., the largest 

 proportion of first-grade fruits of valuable sizes, the small-yielding 

 trees bearing fruit of a poorer grade, of extreme sizes, and of vari- 

 able quality which is of less commercial value than the higher grade 

 and more uniformly sized fruits of the high-yielding trees. 



A plat of 100 Eureka lemon trees, typical of the groves of this 

 variety in California, located near Corona, has been selected for 

 study by the same methods as those used for the study of the navel 

 orange and pomelo varieties. The quantity, quality, and other char- 

 acteristics of the fruit borne by the individual trees in this plat will 

 be determined by regular monthly pickings. 



An increasing number of fruit growers in California are undertak- 

 ing a systematic study of plats of citrus trees by methods similar to 

 those developed by the bureau investigations. As a rule, plats of 100 

 trees under uniform conditions are selected, the fruit of each tree 

 being picked, assorted, and sized, each grade and size being weighed 

 and the fruits counted, so that an accurate record is kept of the yield 

 and commercial quality of fruit from each individual tree. These 

 observations on the important varieties of citrus fruits, made under 

 widely differing soil and other conditions, should add materially to 

 the information on this subject and assist in the practical application 

 of improved scientific methods of bud selection in replacing the un- 

 profitable trees with more uniform and productive strains or varie- 

 ties of citrus fruits. 



EXPERIMENTAL GARDENS AND GROUNDS. 



The work of caring for the greenhouses and grounds of the depart- 

 ment has continued in charge of Mr. E. M. Byrnes. 



Construction and repair or buildings. — The area under glass on 

 the department grounds has been materially increased during the 

 year by the addition of a temporary greenhouse to care for a collec- 

 tion of citrus fruits and of another for the experimental work of 

 the Physical Laboratory. As a precautionary measure, in case there 

 should be a break in the underground steam main which now fur- 

 nishes heat to the greenhouses from the central power station, two 

 large secondhand boilers were installed adjacent to the greenhouses. 

 These two boilers were turned over to the department by the Superin- 

 tendent of the Capitol Buildings and Grounds without cost other than 

 that incident to moving them and setting them in their present posi- 

 tion. Such repairs were made to the older range of greenhouses as 

 were necessary, and five of them w^ere given a coat of paint inside 

 and out. Fire protection was installed in the frame buildings on the 

 north fronts of the ranges of greenhouses. 



Greenhouse operations. — There are now 27 greenhouses devoted 

 to the propagation of trees, plants, and fruits collected by the Office of 

 Seed and Plant Introduction ; general hybridization work ; seed test- 

 ing; experimental work with a collection of citrus and other tropical 

 fruits: experimental work conducted by the Office of Crop Physi- 



