DOUBLE NUMBER, 
VOL. XIX, Nos. 5 & 6. May & June, 1920- 
[Pubushbd July 10th, 1920.] 
THE 
A BRITISH BOTANICAL JOURNAL, 
EDITED BY A. G. TANSLEY, M.A., F.R.S. 
UNIVERSITY LECTURER IN BOTANY, CAMBRIDGE, 
IN CONSULTATION WITH THE STAFF OF THE CAMBRIDGE BOTANY SCHOOL. 
Contents: 
PHYSIOLOGICAL ANATOMY OF XEROPHYTIC SELAGINELLAS. 
[With Text-Figures, I-XII.] .. J. C. Th. Uphof. 
MUTATIONS AND EVOLUTION. Chapters IV and V, ... R. Ruggles Crates. 
LABORATORY NOTE. ON AN IMPROVED METHOD FOR 
DEMONSTRATING THE ABSORPTION OF OXYGEN IN 
RESPIRATION . .. A. W. Bartlett. 
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