iv 
TABLE OF CONTENTS 
No. 5, May 
Page 
Potato ovules with two embryo sacs (with one text figure) 
W. J. Young 213 
Vegetative vigor of the host as a factor influencing susceptibiHty and 
resistance to certain rust diseases of the higher plants II (with 
Plates XI and XII) M. A. Raines 215 
Lignification of mature phloem in herbaceous types (with Plate XIII) 
Carl L. Wilson 239 
Observations on the effect of water-raking on the keeping quality of 
cranberries H. F. Bergman 245 
Incipient drying and wilting as indicated by movements of coconut 
pinnae (with one text figure) Sam F. Trelease 253 
Dr. W. J. Beal's seed-viability experiment H. T. Darlington 266 
Nutrient solutions for wheat. .W. E. Tottingham and E. J. Rankin 270 
No. 6, June 
Comparative studies on respiration XXI. Acid formation and de- 
creased production of CO2 due to ethyl alcohol (with two text 
figures) Marian Irwin and Margaret Weinstein 277 
A new species of Spirogyra with unusual arrangement of the chromato- 
phores (with three text figures) Mabel L. Merriman 283 
The male receptacle and antheridium of Reboulia hemisphaerica (with 
24 text figures and Plate XIV) A. W. Dupler 285 
The meiotic cytokinesis of Nelumbo (with one text figure and Plate 
XV) Clifford H. Farr 296 
Comparative studies on respiration XXII. The effect of lactic acid on 
the respiration of wheat (with two text figures) 
Edith Philip Smith 307 
The effect of transpiration on the absorption of salts by plants 
Walter C. Muenscher 311 
Prairie inclusions in the deciduous forest climax (with two text figures) 
Herbert C. Hanson 330 
No. 7, July 
A preliminary study of Claviceps purpurea in culture (with Plates 
XVI-XXI) Walter W. Bonns 339 
Studies in the genus Gymnosporangium IV. Distribution of the my- 
celium and the subcuticular origin of the telium in G. clavipes 
(with seven text figures and Plate XXII) B. O. Dodge 354 
Certain relations between root development and tillering in wheat: 
significance in the production of high-protein wheat 
W. F. Gericke 366 
The pollination of Marcgravia: a classical case of ornithophily? (with 
five text figures and Plates XXIII and XXIV) . . Irving W. Bailey 370 
