1916] FIELD CEOPS. 437 



The floral biology of the almond, C. Campbell (Atti R. Accad. Lincei, Rend. 

 CI. Set. Fis., Mat. e Nat., 5. ser., 24 {1915), I, No. 3, pp. 256-261, figs. 9).— This 

 is a discussion of anomalies in the floral parts of the almond, pointing to the 

 necessity for study bearing upon the attainment of certainty and regularity in 

 the output. 



Chimeras and graft hybrids, J. Budeb (Naturtcissenschaften, 3 (1915), Nos. 

 1, pp. 6-9, figs. J,; 2, pp. 23-25, figs. 3; 3, pp. 33-36; abs. in Bot. Centbl., 129 

 {1915), No. 2, p. 20). — The author discusses the conditions for the production 

 of graft hybrids and the necessary relations of the cells of the symbionts to 

 each other and to the growing point, which are described in typical forms. 



FIELD CROPS. 



Comparative study of the root systems and leaf areas of com and the 

 sorghums, E. C. Miller (U. S. Dept. Agr., Jour. Agr. Research, 6 (1916), No. 9, 

 pp. 311-332, pis. 7, figs. 3). — The methods and results of experiments conducted 

 at the Garden City, Kans., substation of the Kansas Experiment Station, to 

 determine the fundamental characteristics of sorghum plants enabling them to 

 withstand severe climatic conditions better 'than the corn plant, are described. 

 The data secured, together with a summary of climatic conditions, are given in 

 tables and discussed. 



In all stages of growth the primary root systems were found equally exten- 

 sive, but the secondary roots of the sorghum plants as compared with those of 

 corn were twice as numerous per unit of primary root. Both primary and sec- 

 ondary roots of the sorghums were found to be more fibrous than those of corn. 

 A study of the weight of the dry matter of the aerial portions and of the roots 

 of mature plants showed an average ratio of the dry weight of the grain, stem, 

 ^nd leaves of standard Kafir to the dry weight of the roots of 15 : 1 and 14.9 : 1 

 in 1914 and 1915, respectively, while the dry weight of the stem and leaves of 

 the same plants was on the average 10.9 times that of the root weight in 1914, 

 and 10.1 times the root weight in 1915. The average ratio of the dry weight 

 of the aerial portions of dwarf milo maize to the weight of the roots was found 

 to be 15.7 : 1 in 1914 and 15 : 1 in 1915. The weight of the stem and leaves of 

 the same plants was 9.6 times and 8 times, respectively, the weight of the roots 

 for the two years. The weight of the stem and leaves of Pride of Saline corn 

 was 9.6 times the root weight in 1914 and 7.8 time.s the weight of the root sys- 

 tem in 1915. The aerial parts of dwarf BlackhuU Kafir corn in 1915 showed a 

 weight of 15.7 times that of the roots, and the weight of the stem and leaves 

 8.9 times the weight of the roots. The results of experiments regarding soil 

 moisture content and depth of root penetration seemed to show that under the 

 existing conditions very little, if any, depletion of soil moisture took place be- 

 low the depth of root penetration. 



The leaf area of the corn plant at all stages of its growth was found to be 

 approximately twice as great as that of Dwarf Milo maize and never less than 

 1.5 times that of BlackhuU Kafir corn. It is pointed out that the sorghums 

 would have the advantage over the corn plant under any climatic condition tend- 

 ing to bring about a loss of water from the plants. The two sorghums as com- 

 pared to the corn plant have only one-half the leaf surface exposed for the 

 evaporation of water, and also have a root system which, judging from the 

 number of secondary roots, would be twice as efficient in the absorption of soil 

 moisture. 



Contribution to the question of spacing and feeding the individual plant 

 in plant breeding, R. Leidner (Ztschr. PflanzenzucM.. 3 (1915), No. 3. pp. 

 353-310). — This article discusses the views of different authorities on plant 



