1916] HORTICULTURE. 145 



mercially expressed lemon oil ) was sufficient to cause the typical green spotting. 

 The green color appeared to be fixed in the portion acted on by the oil, while the 

 remainder of the rind colored normally in the usual process of curing in four 

 to six weeks. The action of a large amount of lemon oil, such as 0.1 cc. or more, 

 under the same conditions caused the spots to become brownish or reddish rather 

 than green. When the amount was sufficiently increased the breaking down of 

 the tissue was so great that blue mold started in a few days. When the fruits 

 acted on by the oil were left attached to the tree, only in rare cases did the 

 green color remain. As the fruits continued to grow and mature, the sunken 

 areas were partially restored and only slight scars were left. 



" Under similar conditions the oil from the rind of oranges acted upon other 

 uninjured oranges in the same manner as did the oil from the rind of lemons act 

 upon other lemons. The oil caused the spotting of tender leaves and shoots and 

 the withering of flower buds when squeezed out upon them. The action of the 

 oil on the surface of the rind is extremely rapid, as shown by the fact that 

 0.01 cc. of lemon oil acting for eight seconds was suflicient to show afterward a 

 visible effect on the rind." 



Green spotting has been observed almost exclusively on fruit picked during the 

 late fall, winter, and early spring, which period corresponds to the season of 

 moist atmospheric conditions in California, due to frequent rains and fogs. The 

 remedial measures suggested by the present investigations are picking the fruit 

 when free from rain or dew and the use of extreme care in handling fruit to 

 avoid injuries or knocks that would tend to liberate the oil in the rind. 



Cacao culture, A. Ribeiro de Oastko Sabkinho (O Cacauzeiro e Sua Cultura 

 Intensiva. Rio de Janeiro: Min. Agr., Indus, e Co-m., 1915, pp. 25). — A treatise 

 on cacao culture, including information relative to climatic and soil require- 

 ments, varieties, propagation, planting, cultural operations, intercrops, methods 

 of harvesting, and preparation for market. A brief bibliography on cacao cul- 

 ture is included. 



The date palm in Egypt, T. W. Bkown {Agr. Jour. Egypt, 5 {1915), No. 1-2, 

 pp. 63-79, pi. 1). — An account of the date palm with reference to methods of 

 propagation, planting operations, irrigation, soil, manures, intercrops, rate of 

 growth, and the peculiarities of the male and female palms, with special refer- 

 ence to the process of hand pollination. 



Report of the proceedings at the sixth annual meeting of the Northern 

 Nut Growers' Association, Rochester, N. Y., September 1 and 2, 1915 

 {North. Nut Growers Assoc. Proc., 6 {1915), pp. 77). — In addition to the usual 

 business of the association the following papers read at the meeting, together 

 with a bibliogi-aphy of the year of articles dealing with nuts and various phases 

 of nut cultiu-e, are given : The Relation of Forest Conditions in New York to 

 Possibilities of Nut Growing, by H. P. Baker (pp. 17-23) ; [Nut Survey of Penn- 

 sylvania], by F. N. Fagan (pp. 23-27) ; New Tree Crops and a New Agricul- 

 ture, by J. R. Smith (pp. 30-35) ; Notes on the Hazels, by R. T. Morris (pp. 

 36-51) ; An Appeal to Owners of Hardy Nut Trees, by C. A. Reed (pp. 51-57) ; 

 History, Dimensions, and Crop Records of Parent Northern Pecan Trees, and 

 Notes on the Observation of Propagated Trees, by W. C. Reed (pp. 5S-62) ; 

 Walnut Observations in California, by L. D. Batchelor (pp. 63-68) ; Pruning 

 the Persian Walnut, by .1. G. Rush (pp. 69, 70) ; and Report on Nut Growing 

 in Canada, by G. H. Corsan (pp. 71, 72). 



Lawn making in California, J. W. Gregg {California Sta. Circ. 149 {1916), 

 pp. 8, fig. 1). — This circular contains practical directions for the construction 

 and maintenance of lawns, including also information relative to methods of 

 controlling the weeds, rodents, and insects in lawns. 



