vi CONTENTS 
Rhizophidium polysiphoniae in the United States. 
Contributions from the Hull Botanical Labora- 
tory 292 (with ten figures) - - - - 
Developmental selection in as eer nae 
twenty-eight figures)  - 
Biochemistry of plant diseases (with seven figures) 
Variations in a and gross morphology of 
araxacw I. Contributions from the Hull 
Rotana Labotatacy 293 (with plates IX, X) 
Annularia with reste: fruit Pula two 
figures)-  - 
Cytology of chlorophyll types of maize (with plates 
fee ee ce 
Cultivation of excised root tips and stem tips under 
sterile conditions (with four figures) - 
Influence of wheat seedlings upon the Siateccoes ion 
concentration of nutrient solutions 
[VOLUME LXXIII 
George W. Martin 
John T. Buchholz 
J.J. Willaman and 
W. M. Sandstrom 
Paul B. Sears 
Eda M. Round 
L. F. Randolph 
Wm. J, Robbins 
inus H. Jones and 
John W. Shive 
Sulphur and nitrogen content of alfalfa grown under 
various conditions. Contributions from the 
Hull Botanical Laboratory 294 - - E. H. Hall 
Variation in inked and gross morphology of 
Taraxac II. Contributions from the Hull 
Botanical I Laboratoiy 295 (with nine figures) - Paul B. Sears 
Anatomy of —" —" — seven 
figures)-  _ - - - Isabel M. P. Browne 
Overwintering of tomato mosaic (with plate ANT) Max W. Gardner and 
Stroma and formation of perithecia in Hypoxylon. 
Contributions from the Hull Botanical Labora- 
tory 296 (with plate XVIII and seven figures) 
James B. Kendrick 
Patsy Lupo 
PAGE 
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