Part I. pubhshed August 16, 191 5. 

 Part II. pubhshed December 30, 191 5. 

 Part III. published JVl ay 17, 191 6. 



1 



Hi 



K PI 



fl>rinteD fov tbe IRogal Horticultural Society 



BY 



SPOTTISWOODE, BALLANTYNE & CO. LTD., LONDON, COLCHESTER AND ETON 



