l')19] HORTICULTURE. 741 



good avocado, but is faintly sweetish. The anay grows in moist regions of 

 Guatemala at an elevation of only 300 to 365 meters (984 to 1,197 ft.), hence 

 Popenoe believes that it will not succeed in California, but that it may do 

 well in southern Florida. Seedling trees are now being cultivated in the Plant 

 Introduction Garden at Miami. 



A related species, H. ovaUs n. sp., collected by H. Pittier in Costa Rica 

 several years ago, is also described. 



Further observations upon the application of manure in citrus orcliards 

 with the furrow-manure system, A. D. Shamel (Ca7. Citrogr., 4 (1919), No. 12, 

 pp. 332, 333, figs. S). — The author here describes and illustrates a cheap home- 

 made plow, which has been found to make a much more satisfactory furrow 

 than the ordinary walking plow in applying manure by the furrow-manure 

 system (E. S. R., 40, p. 246). This system is coming into increasing use in 

 California in citrus orchards. 



Efficiency in citrus irrigation, F. M. Eaton (Chula Vista, Cal.: The San 

 Diego Land Corporation [1919], pp. 16, figs. 10). — The author emphasizes the 

 need for greater efficiency in orchard irrigation, and analyzes a few of the 

 factors which must be considered before proper irrigation is possible. Much of 

 the data presented has special application to the Chula Vista district of 

 California. 



Yields of V/ashington navel oranges in relation to pruning, G. Subb (Cal. 

 Citrogr., 4 (1919), No. 11, pp. 290, 325). — A contribution from the California 

 Citrus Station describing pruning experiments started by the station in 1915 

 on a 20-acre grove of Washington navel orange trees, and giving the yields 

 for the four years 1916-1919 under different methods of pruning. 



The average total yields for the four seasons are 100 lbs. per tree lower 

 on heavily pruned trees than on lightly pruned trees. The results, in general, 

 suggest that any improvement in the quality of fruit due to pruning may be 

 more than offset by the greater cost of the resulting smaller crop. Light 

 pruning, in this experiment at least, was more satisfactory than heavy pruning. 



Immature citrus fruits: Laws, rules, and regulations. R. E. Rose (Talla- 

 Jia.ssee. Fla.: T. J. Appleyard, 1918, rev., pp. 24, fig. 1). — This pamphlet contains 

 laws, rules, and regulations defining immature citrus fruits and fixing stand- 

 ards for mature citrus fruits, together with the rules, regulations, and methods 

 for applying the " ratio of acid to total solids " test by inspectors.. Instructions 

 to growers for applying the test are also given. 



Cocoa production in the British Empire (Bui. Imp. Inst. [So. Kensington}, 

 11 (1919), No. 1, pp. 40-95). — A comprehensive account of the present produc- 

 tion of cocoa within the British Empire, including also statistics on cocoa 

 production in foreign countries. 



Eirst report on activities in connection w^ith the selection of coffee and 

 cacao, G. Stahel (Dcpt. Landb. Suriname Bui. 36 (1919), pp. 24). — An account 

 of work accomplished in the selection and recording of high-yielding trees, the 

 propagation of stocks, and budding and grafting, and In the increase of propa- 

 gating wood on particularly good yielding trees. 



Improvement of coffee by seed selection and hybridization, R. D. Anstead 

 (Agr. Jour. India, 14 (1919), No. 4, pp. 639-644). — A paper on this subject in 

 which the author calls attention to some results of hybridization and selection 

 work with coffee in the Dutch East Indies and South India. 



At Dubari, A. H. Jackson has produced a hybrid which is fertile and comes 

 true to seed. It is a vigorous, healthy type of arahica coffee, apparently 

 disease- resistant to a high degree. It comes into bearing early and gives a 

 high yield. 



