vi CONTENTS [VOLUME LVII 
Life history of Porella platyphylla. Contributions 
from the Hull Botanical Laboratory 184 (with 
plates XV and XVI) - - - - - Florence L. Manning 
The effect of climatic conditions on the rate of 
growth of date palms (with one figure) - - A. E. Vinson 
The probable origin of Oenothera Lamarckiana Ser. 
(with plates XVII-XIX) Hugo De Vries 
The spur shoot of the pines (with sates XX- 
XXIII and two text figures) - - - Robert Boyd Thomson 
A physiological study of the germination of Avena 
fatua. Contributions from the Hull Botanical 
Laboratory 185 (with thirteen figures) - - W.M. Atwood 
Undescribed plants from Guatemala and oth 
Central American Republics. XXXVIII - John Donnell Smith 
The ovary and embryo of Cyrianthus sanguineus. 
Contributions from the Hull Botanical Lab- 
oratory 186 (with aes XXIV and three text 
figures) - : _ - - - Margaret Elizabeth Farrell 
Winter as a factor in the xerophily of certain ever- 
green ericads (with twelve text figures) - - Frank Caleb Gates 
The morphology of Araucaria brasiliensis. II. 
The ovulate cone and female gametophyte 
(with plates XXV-XXVII and two text 
figures) - -  L. Lancelot Burlingame 
The origin of Diccieiae beciies 
from the Hull Botanical Laboratory 187 itt 
plates XXVIII and XXIX and two tex 
figures) - = -- - John M. Coal and W. J. G. Land 
A method of ining the temperature of the 
paraffin block and microtome knife. Con- 
tributions from the Hull Botanical -acuaals 
188 (with two figures) - - W. J. G. Land 
BRIEFER ARTICLES— 
A method of handling material to be imbedded in 
paraffine (with one figure) = - - Winfield Dudgeon 
The relation between the tide. stream and 
the absorption of salts - - - - Heinrich Hasselbring 
The type species of Danthonia A. S. Hitchcock - 
A method of handling material to ol imbedded i nb 
paraffine (with one —_ - Elda R. Walker 
A correction - —. e e e E. M. East. 
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