Acknowledgment. 



This v/ork was undertaken at the suggestion of 

 Dr. T), S, Johnson and was carried out with his guid- 

 ance. Tho HuV.ioc wishes to 'express his sincere thanks 

 to him for sympathetic guidance and instruction. His 

 thanks are also due to Professor Brooks for much kind- 

 ly instruction, help and advice. He is also indebted 

 i;o Professor Hov/ell, Dr. Andrews, Br, Dryer, and Dr. 

 Drew, for advice and instruction. He v/ishes moreover 

 to express t'ae sense of personal loss he feels from 

 the death of Dr, Ihxmphrey, under wn.om his botanical 

 work began. 



