736 EXPEEIMENT STATION RECORD. [Vol.36 



practices relative to tlie growing of fall-sown grains in Delaware, Maryland, 

 A^'irginia, and West Virginia, with recommendations as to the best varieties of 

 the various grains to gi'ow, based on tests made with winter wheat (bearded 

 and beardless), winter spelt and emmer, winter rye, winter oats, and winter 

 barley. 



Seed-flax production, C. H. Clark {U. S. Dept. Agr., Farmers' Bui. 785 

 (1917), pp. 19, figs. 9). — This discusses the methods and practices of flax- 

 seed production in the United States, emphasizing not only the value of flax on 

 new sod but also its possibilities in the older agricultural districts. 



Flax varieties grown in the United States are roughly divided into (1) seed 

 flax, (2) short fiber flax, and (3) textile fiber flax. In tests at 10 stations in 

 the nortliern Great Plains area west of the Red River valley, where flax wilt 

 is not serious, the seed-flax varieties have given uniformly better results than 

 the short fiber flaxes. North Dakota No. 155, or some selection from it, has 

 usually given the highest yield, while North Dakota Resistant Nos. 52 and 

 73 and similar strains have also proved excellent varieties. 



In subhumid sections farther east. North Dakota Resistant No. 114 and 

 Primost (Minnesota No. 25) have been widely di.stributed. 



Tests with flax in a 6-year rotation of 3 years of alfalfa and 1 year each of 

 corn, flax, and sugar beets In comparison with flax grown continuously have 

 been conducted at the Belle Fourche and Huntley experiment farms (E. S. R., 

 33, p. 829 ; 36, p. 132). At Huntley the average yiehl of flax in the rotation for 

 the first 4-year period was 25.8 bu., the highest yield being 31.3 bu. The average 

 yield of continuously cropped plats was 10.1 bu., and the highest yield 14.5 bu. 

 The yield of the continuously cropped field has increased each year. 



Similar results were obtained at the Belle Fourche station. The 1914 flax 

 plat in the 6-year rotation yielded 21.4 bu., while the yield of the continuously 

 cropped plat was 7.5 bu. 



A rotation similar to the above in the irrigated rotation series at the Scotts- 

 bluff experiment farm has not given as satisfactory results, due largely to un- 

 favorable weather conditions. These tests are being continued. 



Change of sex in hemp, F. J. Pkitchard (Jour. Heredity, 7 (1916), No. 7, 

 pp. 325-329, fig. 1). — The differences of opinion regarding the effect of external 

 stimuli upon sex ratios led the author to undertake investigations with hemp in 

 an effort to determine the following: (1) Can sex ratios of dioecious plants be 

 altered by modifying conditions external to their germ cells? (2) Is the altera- 

 tion thus obtained limited to individuals of one sex? (3) How do results har- 

 monize with the Mendelian conception of sex determination? 



The hemp plant was employed because it is almost wholly composed of dis- 

 tinctly unisexual individuals, although monoecious individuals (which were dis- 

 tinctly female in type) also appeared. The plant's physiological equilibrium 

 was disturijed by the removal of flowers and other vegetative parts and by the 

 injection of the following chemical substances into the stem : Calcium nitrate 

 0.1, zinc sulphate 0.1, dextrose 5, maltose 5, peptone 1, asparagin 0.5, potassium 



iodid 3 per cent, pyridin hr' formic acid TgnQn' acetic acid ^> hq' sodium 



hydrate hqa' tqq' njn Two hundred and sixty-three plants were mutilated by 



the removal of flowers, flower bu3s, leaves, and portions of the stem. The tops 

 of 20 were bagged and 60 others received injections of the above-named chemi- 

 cals. The discussion covers the results obtained from two years' experimental 

 work. 



Alteration of sex occurred under several dift'erent treatments, the removal of 

 parts being the only factor, however, common to all the sex-developing responses. 



