CONTENTS IX 



Paper P^«^ 



XXII. Effects of Different Regions of the Visible Spectrum upon 



Seed Plants 763 



H. W. Popp, Associate Professor of Botany, Pennsylvania State 



College, State College 



F. Brown, Instructor in Botany, Pennsylvania State College, State 



College 



XXIII. Effect of the Visible Spectrum upon the Germination of 



Seeds and Fruits 791 



William Crocker, Managing Director, Boyce Thompson Institute for 

 Plant Research, Inc., Yonkers, N.Y. 



XXIV. The Effects of Visible and Ultra-violet Radiation on the 



, Histology of Plant Tissues 829 



J. T. Buchholz, Professor of Botany, University of Illinois, Urbana 



XXV. Some Infra-red Effects on Green Plants 841 



John M. Arthur {see Paper XX) 



XXVI. The Effect of Ultra-violet Radiation upon Seed Plants . . 853 

 H. W. Popp and F. Brown {see Paper XXII) 



XXVII. The Effects OF Radiation on Fungi 889 



Elizabeth C. Smith, Research Assistant, University of Wisconsin, 

 Madison 



XXVIII. The Problem of Mitogenetic Rays . 919 



Alexander Hollaender, Research Associate (under auspices of 

 National Research Council), University of Wisconsin, Madison 



XXIX. Effects of X-rays upon Green Plants 961 



Edna L. Johnson, Associate Professor of Biology, University of 

 Colorado, Boulder 



XXX. The Effects of Radium Rays on Plants 987 



C. Stuart Gager, Director, Brooklyn Botanic Garden, Brooklyn 



XXXI. The Light Factor in Photosynthesis 1015 



H. A. Spoehr, Chairman, Division of Plant IMology, Carnegie Insti- 

 tution of Washington, Stanford University, California 

 J. H. C. Smith, Staff Member, Division of Plant Biology, Carnegie 

 Institution of Washington, Stanford University, California 



XXXII. The Influence of Radiation on Plant Respiration and Fer- 

 mentation 1059 



Charles J. Lyon, Professor of Botany, Dartmouth College, Hanover, 

 N.H. 



XXXIII. Growth Movements IN Relation TO R.\diation 1073 



Earl S. Johnston, Assistant Director, Division of Radiation and 

 Organisms, Smithsonian Institution, Washington, D.C. 



