4 AGRONOMY [Bot. Absts., Vol. V, 



crop production are discussed. The above results showing the significance of the length of 

 day in sexual reproduction were confirmed by the use of incandescent electric lights to lengthen 

 the normal daily illumination period during the winter months. Under suitable exposures 

 Fagopyrum vulgar e, Spinacea oleracea and other plants assumed the ever-blooming type of 

 development. Although the plants of buckwheat showed general similarity in behavior under 

 the normal illumination of the short winter days, the individuals growing under the influence 

 of the lengthened illumination period manifested striking differences among themselves in 

 time of flowering and in size attained. Under controlled conditions differences in water sup- 

 ply and light intensity were without effect on the time of flowering of soy beans. It is tenta- 

 tively concluded that: Sexual reproduction can be attained by the plant only when it is ex- 

 posed to a specifically favorable length of day (the requirements in this particular varying 

 widely with the species and variety), and exposure to a length of day unfavorable to reproduc- 

 tion but favorable to growth tends to produce gigantism or indefinite continuation of vege- 

 tative development, while exposure to a length of day favorable alike to sexual reproduction 

 and to vegetative development extends the period of sexual reproduction and tends to induce 

 the "ever-bearing" type of fruiting. The term photoperiodism is suggested to designate the 

 phenomena disclosed. A bibliography is appended. — W. W. Garner. 



23. Hawtrey, S. H. C. Notes on a few useful plants and home industries of Paraguay. 

 South African Jour. Indust. 3: 35-41. 1920. 



24. Helyar, J. P. Report of the Department of Seed Analysis. New Jersey Agric. 

 Exp. Sta. Ann. Rept. 1918: 93-97. 1919. — Gives a summarization of the tests for field crop 

 seeds, vegetable seeds and corn. — Mel. T. Cook. 



25. Hendry, G. W. Mariout barley with a brief discussion of barley culture in Cali- 

 fornia. California Agric. Exp. Sta. Bull. 312: 57-109. Fig. 19. 1919.— A brief history of 

 Mariout barley is given, including an account of its introduction into the United States. The 

 bulletin is devoted mainly to a discussion of the practical aspects of barley culture in Cali- 

 fornia. The moisture and soil requirements, methods of preparing the soil and seeding, meth- 

 ods of harvesting the crop and comparative yields in different states are discussed. — W. P. 

 Kelley. 



26. Hepner, Frank E. Wyoming forage plants and their chemical composition. Wyo- 

 ming Agric. Exp. Sta. Ann. Rept. 28 (1917-18): 117-128. 1918.— This paper consists of two 

 parts. Part I deals with the relation of the soil to the nitrogen content of high altitude 

 plants. In earlier work done at this station (Wyoming Agric. Exp. Sta. Bulls. 65, 70, 76, and 

 87) it was discovered that the native plants were richer in nitrogen than those of the same 

 species grown in the more humid climates of lower altitudes, and later investigations devel- 

 oped the fact that there was a tendency for the nitrogen content to increase with the altitude. 

 In an attempt to find out whether the cause of this increase might not be found in the higher 

 nitrogen content of the soil at higher altitudes, 54 samples of 33 different species of grasses, 

 sedges and rushes were collected at different altitudes and at the same time the soils on which 

 they grew were sampled. These were analyzed and the results are given in tabular form. 

 These results appear to show that the increase of nitrogen in the plants at higher elevation 

 is not so marked as the earlier work would indicate, although the statements made in the ear- 

 lier bulletins were generally true. Regarding the question as to whether the soils of high alti- 

 tudes are richer in nitrogen than those of lower elevations, the conclusion is that although 

 nitrogen in the soil is practically the sole source of the nitrogen in the plant, and that the quan- 

 tity present doubtless exerts a considerable influence on the amount taken up by the plant, 

 still the abundance of nitrogen found in high altitude grasses is not due entirely, if at all, to 

 the greater amount of nitrogen, either total or nitrate, in the soils, nor is it due to excessive 

 quantities of any other soil constituent. Part 2 gives the complete proximate analyses of 

 some of the forage plants including those dealt with in the previous paper. They are all 

 Grasses, Sedges, and Rushes, including Agropyron occidenlale Scribn. ; Agropyron pseudo- 



