Annals of Botany 
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 
D. 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., LL.D., 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 
VOLUME XXXVI 
With twenty-one Plates and two hundred and eighteen Figures in the Text 
LONDON 
HUMPHREY MILFORD, OXFORD UNIVERSITY PRESS 
AMEN CORNER, E.C. 
Edinburgh, Glasgow, New York, Toronto 
Melbourne, Cape Town, and Bombay 
1922 
