Ubc Botanical (Basette 



/ftontbls 



Edited by John M. Coulter and Charles R. Barnes, with the assistance of other members of the 



botanical staff of the University of Chicago. 



Vol. XLIV, No. 6 



Issued 



CONTENTS 



ON TWIN HYBRIDS. J/ugo de Vries 



J 



A CONTRIBUTION TOWARD A KNOWLEDGE OF THE GENUS WASHINGTONIA 



(with twelve figures). S, B. Parish - . - ' 



ARAUCARIOPITYS, A NEW GENUS OF ARAUCARIANS (with plates xxvii-xxx). 



Edward C. Jeffrey --...... 



DIFFERENTIATION OF SPOROCARPS IN AZOLLA. Contributions from the Hull 



401 



408 



435 



Botanical Laboratory 105 (with plates xxxi and xxxii). Wanda M. Pfdffer - - 445 

 CURRENT LITERATURE 



BOOK REVIEWS - 455 



r 



THE NATURE AND DEVELOPMENT OF PLANTS. EVOLUTION IN POTATO BEETLES. VEGE- 



TABLE PHYSIOLOGY. 



MINOR NOTICES - 

 NOTES FOR STUDENTS 



NEWS 



458 



459 



464 



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