PRACTICAL TEXT- BOOK 



OF 



PLANT PHYSIOLOGY 



DANIEL TREMBLY MACDOUGAL, Ph.D. 



Director of the Laboratories of the New York Botanical Garden. 



With One Hundred and Fifty-nine Illustrations. 



LONGMANS, GREEN, AND CO. 



91 and 93 FIFTH AVENUE, NEW YORK, 



LONDON AND BOMBAY. 



1 901. 



