LITERATURE CITED 
(1) Beal, W. J. 
1887-1896. grasses of north America. 2 vols, illus. New York. 
(2) Britton, N. L. 
1901. MANUAL OF THE FLORA OF THE NORTHERN STATES AND CANADA. 
1080 pp. New York. 
(3) Carrier, L. 
1917. THE IDENTIFICATION OF GRASSES BY THEIR VEGETATIVE CHARACTERS. 
U. S. Dept. Agr .Bui. 461, 30 pp., illus. 
(4) Chase, A. 
1922. first book of grasses. 121 pp., illus. New York. 
(5) Clark, C. F. 
1910. variation and correlation in timothy. N. Y. Cornell Agr. Exp. 
Sta. Bui. 279:301-350, illus. 
(6) Collins, G. N. 
1914. A drought-resisting adaptation in seedlings of hopi maize. 
Jour. Agr. Res. 1 : 293-302, illus. 
(7) Coulter, J. M. 
1915. THE ORIGIN OF MONOCOTYLEDONY. II. MONOCOTYLEDONY IN 
grasses. Ann. Mo. Bot. Gard. 2 : 175-183, illus. 
(8) Darwin, C. R. 
1881. the power of movement in plants. 592 pp., illus. New York. 
(9) Evans, M. W. 
1916. THE FLOWERING HABITS OF TIMOTHY. JOUT. Amer. SOC. Agl'On. 
8:299-309, illus. 
(10) Flint, C. L. 
1864. grasses and forage plants. Ed. 6, 398 pp., illus. Boston. 
(11) Garner. W. W., and Allard, H. A. 
1923. FURTHER STUDIES IN PHOTOPERIODISM, THE RESPONSE OF THE PLANT 
TO RELATIVE LENGTH OF DAY AND NIGHT. JOUl\ Agr. ReS. 23 I 
871-920, illus. 
(12) GOEBEL. K. E. 
1900-05. organography of plants. Trans, by I. B. Balfour. 2 vols., 
illus. Oxford. 
(13) Hackel, E. 
1890. the true grasses. Trans, by F. Lamson-Scribner and E. A. 
Southworth. 228 pp., illus. New York. 
(14) 1890. UBER EINIGE EIGENTHUMLICHKEITEN DER GRASER TROCKENER KLI- 
mate. Yerhandl. k. k. Zool.-Bot. Gesell. Wien. 40 : 125-138. 
(15) Hayes, H. K., and Barker. H. D. 
1922. the effects of self-fertilization in timothy. Jour. Amer. 
Soc Agron. 14:289-293. 
(16) Hays. W. M., and Boss. A. 
1899. Wheat. Minn. Agr. Exp. Sta. Bui. 62 : 321^t93, illus. 
(17) Hitchcock, A. S. 
1914. a textbook of grasses. 276 pp., illus. New York. 
(18) 1920. THE GENERA OF GRASSES OF THE UNITED STATES. U. S. Dept. Agr. 
Bul. 772, 307 pp., illus. 
(19) Holm, T. 
1908. OBSERVATIONS ON' SEEDLINGS OF NORTH AMERICAN PHAENOGAMOUS 
plants. Ottawa Nat. 22 : 165-174, illus. 
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