HORTICULTURE. 739 



powdorefl form, iisiug air as a carrier, witli better commercial results in the 

 control of preventable apple diseases and of apple insects than can be obtained 

 by spraying. Some general suggestions based on the experimental work are 

 given relative to spraying materials, method, thoroughness, and time of applica- 

 tion, home mixing of materials, applicability of the dust method, and equip- 

 ment. 



Blight-resistant roots. — The first step toward pear blight coutrol, A. L. 

 WisKEii (Mo. Bui. Com, Hort. Cal., 5 (IDIG), Xo. 2, pi). JfS-SS, fly. i).— An ad- 

 dress before the State Fruit Growers' Convention, at Palo Alto, Cal., in July, 

 1915, in which the author deals particularly with our present knowledge of 

 blight-resistant roots. 



The taxonomic value and structure of the peach leaf glands, C. T. GREcorvY 

 (New York Cornell Sta. Bui. 3G5 {1915), pp. 183-222, fiys. 9S).— The investiga- 

 tion here reported was undertaken primarily to determine whether peach leaf 

 glands are sufficiently stable and uniform in their characters to be used as a 

 basis for separating the varieties into sections. The leaves used in the work 

 were obtained from the peach district along Lake Ontario, from the Missouri 

 Fruit Station, and from the New York State Station at Geneva. 



The glands of all the leaves were carefully examined and ai-e here discussed 

 with reference to their morphology, physiology and histology, comparison with 

 the spines of the leaf, secretory process, decomposition, and variability. A 

 number of drawings of certain glands are also included. The available litera- 

 ture on the subject was consulted and is here listed. 



Among the varieties studied four kinds of leaves were found, those with 

 reniform glands, those with globose glands, glaudless leaves, and leaves having 

 mixed or indistinctive glands. The great majority of varieties were found to 

 have very definitely shaped glands, whereas other varieties were found that 

 were not adapted to any fixed classification because of the variability of the 

 glands. In view of this variability in conditions it is considered inadvisable to 

 attempt a definite classification into sections, but a list of varieties is given 

 with their gland characteristics, the commercial varieties of New York State 

 being especially considered and illustrated. 



The structure of the glands shows that they are true glands having an upper 

 layer of long, rectangular, secretory cells that produce a sweet substance, the 

 function of which is .hot apparent. After the glands have ceased secreting 

 they begin to decay and slowly disappear until almost nothing is left. The 

 decaying process is preceded in every case by a suberization and thickening 

 of the cell walls. A study of the transitional forms indicates that the glands 

 are merely modified leaf spines. The leaves with reniform glands are appar- 

 ently the highest type and the glandless leaves the lowest type. Whenever 

 typical glandless leaves become possessed of glands they are always of the 

 globose type. The margins of normally glandless leaves are deeply and doubly 

 serrate while the margins of leaves with glands are always single and crenate. 

 The development of glands on a normally glandless leaf is accompanied by the 

 transformation of the serrations to crenations. 



Cost of a peach orchard, C. J. Hayden {Country Gent., 81 {1916), No. 7, p. 

 329). — Data are given on the cost of establishing and maintaining a peach 

 orchard of 10,000 trees during the first three years. 



Report on experiment in picking, packing, handling, cool storage, and 

 transportation of peaches, E. Meeking {Jour. Dept. Ayr. Victoria, 14 {1916), 

 No. 1, pp. 41-55, figs. 3). — Tabular results are given on some cooperative peach 



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