FIELD CROPS. 433 



would also result in au acceleration of growth sufficient to make their use 

 financially profitable." 



The physiology of the pollen of Zea mays with special regard to vitality, 

 D. I. Andronescu {Thesis, Univ. III., 1915, pp. 36, pis. 4). — The author shows 

 by numerous tables and plates as results of field and laboratory studies of 

 maize pollen that the chemical composition of the ix)llen Srcems to be influenced 

 by selection for protein in the kernels. There is evidence of an increase in 

 size of pollen in an Fi generation. In certain media maize pcUen throws out 

 a protoplasmic expansion. There is considerable difference in the germination 

 of pollen of different varieties of maize, and a great variation in the germina- 

 tion of pollen from different tassels of an unselected or unfixed variety of maize. 



Dry heat is injurious to the vitality of the pollen while moist heat can be 

 resisted. Pollen exposed in the laboratory died in two hours, uncovered out 

 of doors it lived four hours, in 60 per cent moisture it lived six hours, in a 

 saturated atmosphere it lived 48 hours, and in hermetically sealed tubes it 

 kept its vitality for 24 hours regardless of external conditions. Pollen from 

 early suckers is as viable as pollen from the parent plants, but that from late 

 suckers gives a low percentage of germination. Low temperature (from 8 to 

 14° C.) has a stimulative effect upon the vitality of the pollen, including that 

 of late suckers. 



Grades for commercial com, J. W. T. Duvel (U. S. Dept. Agr. Bui. 168 

 {1915), pp. 11, pi. 1, figs. 9). — This bulletin gives the grade classification of 

 white, yellow, and mixed corn promulgated by this Department, showing the 

 maximum of moisture and other factors; discusses methods of determining 

 the various factors; and describes the sieves, moisture tester (E. S. R., 24, p. 

 215), and the color plate used in making the determinations. 



Cotton cultivation in Italian Somaliland, G. Scassellati-Sfoezolini {Agr. 

 Colon. [Italy], 9 {1915), No. 4-5, pp. 193-208, pis. ^).— This article describes 

 varieties of cotton and methods of cultivation employed in the colony station 

 on the east coast of Africa. Tables show meteorological data, and analyses of 

 soils and of the parts of the cotton plant, fiber, seed, capsule, leaves, stems, 

 and roots. 



The world's cotton crops, J. A. Todd {London: A. & C. Black, Ltd., 1915, pp. 

 XIII -^Jf60, pis. Jf2, figs. 6). — ^This book treats of the geographical distribution 

 of cotton, the uses of the fiber and of the seed, and the effects of the war on 

 the industry. 



The industrial fi.ber plants of the Philippines, T. Mtjlleb {Jour. N. Y. Bot. 

 Gard., 16 {1915), No. 184, PP- 69-19, pis. 2).— This describes several species of 

 palms, screw pines, grasses, sedges, vines, and other fiber plants, the methods 

 of obtaining the fibers, and their uses. 



ISTotes on hops, 1912-1914, E. S. Salmon {Jour. Southeast. Agr. Col. Wye, 

 No. 22 {1913), pp. 499-532, pis. 8, fig. i).— This describes seedlings of crosses of 

 selected English, German, and American hops and shows the percentage of 

 soft resins in individual plants derived from the various crosses. 



A new variety of hop, the "foundling,'* E. S. Salmon {Jour. Bd. Agr. 

 \ London], 22 {1915), No. 2, pp. 136-140, pis. 3). — This describes a new variety 

 of hop found at Wye College. It has been thoroughly tested since 1908 and is 

 noted as having good cropping qualities ; high resin content ; marked resistance 

 to, if not total immunity from, the " nettle-head " disease ; and lateness of 

 season. 



Influence of color of seed potatoes on the yield, R. Schandee {Tllus. Landw. 

 Ztg., 35 {1915), No. 35, pp. 229, ^30).— This gives results of experiments in 

 1914 that indicate the influence of color on the yield and vigor of the crop. 

 Larger yields were noted for the dark-colored tubers in the variety Wohltmann. 



