Vol. XXXVI. No. CXLII. April, 1922. 
Price 15s. net. 
EDITED BY 
V. H. BLACKMAN, Sc. D., F.R.S. 
/ 
PROFESSOR OF PLANT PHYSIOLOGY AND PATHOLOGY, IMPERIAL COLLEGE OF 
SCIENCE AND TECHNOLOGY, LONDON 
AND 
R. THAXTER, M.A., Ph.D. 
PROFESSOR OF CRYPTOGAMIC BOTANY IN HARVARD UNIVERSITY, CAMBRIDGE, MASS., U.S.A, 
_ • - ASSISTED BY 
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Do H. SCOTT, M.A., LL.D., D.Sc., F.R.S. 
LATELY HONORARY KEEPER OF THE JODRELL LABORATORY, ROYAL BOTANIC GARDENS, KEW 
J. B. FARMER, M.A., D.Sc., F.R.S. 
^PROFESSOR OF BOTANY, IMPERIAL COLLEGE OF SCIENCE AND TECHNOLOGY, LONDON 
F. W. OLIVER, *M.A., D;Sc., F.R.S. 
QUAIN PROFESSOR OF BOTANY; UNIVERSITY COLLEGE, LONDON 
AND OTHER BOTANISTS 
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LONDON 
HUMPHREY MILFORD, OXFORD UNIVERSITY PRESS 
AMEN CORNER, E.C. 
Edinburgh, Glasgow, New York, Toronto 
Melbourne, Cape Town, and Bombay 
1922 
Printed in England at the Oxford University Press. 
