[Vol. io, 
484 AMERICAN JOURNAL OF BOTANY 
Hatton, R. G., and Amos, J. 1921. The running off of black currants. Jour. Pomol. 2: 
1 - 39 * 
Harvey, E. M., and Murneek, A. E. 1921. The relation of carbohydrates and nitrogen 
to the behavior of apple spurs. Ore. Agr. Exp. Sta. Bull. 176: 1-47. 
Heinicke, A. J. 1917. Factors influencing the abscission of flowers and partially de¬ 
veloped fruits in the apple (Pyrus malus L.). Cornell Agr. Exp. Sta. Bull. 393: 
43-114. 
Hooker, H. D. 1921. Seasonal changes in the chemical composition of apple spurs. 
Mo. Agr. Exp. Sta. Res. Bull. 40: 1-51. 
Knight, L. I. 1917. Physiological aspects of self-sterility of the apple. Proc. Amer. Soc. 
Hort. Sci. 1917: 101-105. 
Kraus, E. J., and Kraybill, H. R. 1918. Vegetation and reproduction with special 
reference to the tomato. Ore. Agr. Exp. Sta. Bull. 149: 1-90. Figs. 1-22. 
Lewis, C. I., and Vincent, C. C. 1909. Pollination of the apple. Ore. Agr. Exp. Sta. 
Bull. 104: 3-40. 
Roberts, R. H. 1920. Off-year apple bearing and apple spur growth. Wis. Agr. Exp. 
Sta. Bull. 317: 1-34. 
Sutton, Ida. 1918. Report on tests of self-fertility in plums, cherries, and apples at the 
John Innes Horticultural Institution. Jour. Genetics 7: 281-300. Figs. 1-3. 
Tufts, W. P. 1919. Almond pollination. Cal. Agr. Exp. Sta. Bull. 306: 337-366. 
Valleau, W. D. 1918. Sterility in the strawberry, Jour. Agr. Res. 12: 613-670. 
Waite, M. B. 1895. Pollination of pear flowers. U. S. Dept. Agr. Div. Veg. Path. Bull. 
5: 1-110. 
Wellington, R., Hatton, R. G., and Amos, J. 1921. The “running off” of black currants. 
Jour. Pomol. 2: 160-198. Pis. 1-4. 1921. 
[Whitten, J. C.] 1913. Department of horticulture. In Report of the director for the 
year ending June 30, 1913. Univ. of Mo. Agr. Exp. Sta. Bull. 117: 427-430. (P. 
4 2 9 -) 
Wiggans, C. C. 1918. Some factors favoring or opposing fruitfulness in the apple. Mo. 
Agr. Exp. Sta. Res. Bull. 32: 1-60. 
