TABLE OF CONTENTS 
No. 4, April 
A three-salt nutrient solution for plants John W. Shtve 157 
Preliminary note on the morphology of Gnetum. 
W. P. Thompson 161 
The persistence of viable pycnospores of the chestnut blight 
fungus on normal bark below lesions. 
R. A. Studhalter and F. D. Heald 162 
A taxonomic study of Setaria italica and its immediate allies. 
F. Tracy Hubbard 169 
No. 5, May 
The morphology and systematic position of Podomitrium (with 
seven text figures) Douglas Houghton Campbell 199 
On the relation of root growth and development to the temperature 
and aeration of the soil (with five text figures). 
W. A. Cannon 211 
The anatomy of a hybrid Equisetum (with plates V-VHI). 
Ruth Holden 225 
Some features in the anatomy of the Malvales (with plates 
IX-XI) C. C. FoRSAiTH 238 
The absorption of ions by living and dead roots. 
H. V. Johnson 250 
No. 6, June 
The exchange of ions between the roots of Lupinus albus and 
culture solutions containing one nutrient salt (with thirteen 
text figures). 
Rodney H. True and Harley Harris Bartlett 255 
Notes on the forms of Castela Galapageia (with ten text figures). 
Alb AN Stewart 279 
The development of Pyronema confluens var. inigneum. 
William H. Brown 289 
New or noteworthy grasses A. S. Hitchcock 299 
No. 7, July 
The exchange of ions between the roots of Lupinus albus and 
culture solutions containing two nutrient salts (with three 
text figures). 
Rodney H. True and Harley Harris Bartlett 311 
