CONTENTS 



Page 



Atkinson, Geo. F. The genus Endogone i 



Blakeslee, a. F., and B. T. Avery, Jr. A vegetative reversion 



in Portulaca i8 



Britton, N. L. The flora of the American Virgin Islands 19 



Burns, George P. Weather conditions and phint development . 119 



Cook, Mel T. Modern applications of botany 123 



Dodge, B. O. Studies in the genus Gymnosporajigiiim — I. Notes 

 on the distribution of the mycelium, bufTer cells, and the 



germination of the aecidiospore 128 



East, E. M. Intercrosses between self-sterile plants 141 



Harper, R. A. Binary fission and surface tension in the de- 

 velopment of the colony in Volvox 154 



Harris, J. Arthur. Further studies on the interrelationship of 

 morphological and physiological characters in seedlings of 



Phaseolus 167 



Harshberger, John W. American heaths and pine heaths. ... 175 

 HoLLicK, Arthur. Some botanical problems that paleobotany 



has helped to solve 187 



Howe, Marshall A. Further notes on the structural dimorph- 

 ism of sexual and tetrasporic plants in the genus Galaxaura . . 191 



Jackson, H. S. The Uredinales of Oregon 198 



Jeffrey, Edward C. Evolution by hybridization . . '. 298 



Kunkel, L. O. a method of obtaining abundant sporulation in 



cultures of Macrosporium solani E. & M 306 



Macfarlane, John MuiRHEAD. Synchronism in plant structures 313 

 Metcalf, Haven. The problem of the imported plant disease 



as illustrated by the white pine blister rust 327 



Murrill, William A. The rosy-spored Agarics of North America 334 

 Olive, Edgar W. The cytological structure of Botryorhiza Hip- 



pocrateae 337 



Osterhout, W. J. V. The nucleus as a center of oxidation .... 342 

 Reed, George M, Physiological specialization of parasitic 



fungi 348 



Rowxee, W. W. Relation of marl ponds and peat bogs 410 



Shear, C. L. Pathological problems in the distribution of perish- 

 able plant products 415 



Stewart, F. C. Tubers within tubers of Solanum tuberosum . . . 423 



V 



