Peirce, George J.— American Botany 81 



Phillips, F. J.— Conifers Without Normal Whorls 66 



Pieters, A. J. — The Commercial Raising of Seeds 



Shreve, Forrest — The Establishment Behavior of the Palo Verde 289 

 ■ The Influence of Low Temperatures on the Dis- 

 tribution of the Giant Cactus 136 



Thornber, J. J. — Plant Acclimatization in Southern Arizona 15 



