548 
Journal of Agricultural Research 
Vol. XXVIII, No. 6- 
(5) Jaczewski, A. von. 
1910. STUDIEN UBER DAS VERHALTEN DES SCHWARZROSTES DES GETREIDE& 
in russland. Ztschr. Pflanzenkrank. 20: 321-359, illus. 
(6) Levine, M. N. 
1923. A STATISTICAL STUDY OF THE COMPARATIVE MORPHOLOGY OF BIO¬ 
LOGIC forms of puccinia GRAMiNis. Jour. Agr. Research 24: 
539-568, illus. 
(7) - an( i Stakman, E. C. 
1923. BIOLOGIC SPECIALIZATION OF PUCCINIA GRAMINIS SECALIS. (Ab¬ 
stract) Phytopathology 13: 35. 
(8) Pearl, R., and Miner, J. R. 
1914. A TABLE FOR ESTIMATING THE PROBABLE SIGNIFICANCE OF STATIS¬ 
TICAL constants. Maine Agr. Exp. Sta. Bui. 226: 85-88. 
(9) Rosen, H. R., and Kirby, R. S. 
1919. A COMPARATIVE MORPHOLOGICAL STUDY OF AECIA OF FOUR DIFFER¬ 
ENT RUSTS FOUND UPON BARBERRIES IN NORTH AMERICA. Phy¬ 
topathology 9: 569-573, illus. 
(10) Rosenbaum, J. 
1917. studies of the genus phytophthora. Jour. Agr. Research 8 : 
233-276, illus. 
(11) Stakman, E. C., and Levine, M. N. 
1919. effect of certain ecological factors on the morphology of 
the urediniospores of puccinia graminis. Jour. Agr. Re¬ 
search 16: 43-77. 
( 12 ) - 
1922. THE determination of biologic forms of puccinia graminis on 
triticum spp. Minn. Agr. Exp. Sta. Tech. Bui. 8, 10 p., illus. 
(13) -and Bailey, D. L. 
1923. biologic forms of puccinia graminis on varieties of avena 
spp. Jour. Agr. Research 24: 1013-1018, illus. 
(14) - and Piemeisel, F. J. 
1917. biologic forms of puccinia graminis on cereals and grasses. 
Jour. Agr. Research 10: 429-496, illus. 
