UNITED STATES 



DEPARTMENT OF AGRICULTURE 



CIRCULAR No. 66 



Washington, D. C. June, 1929 



CACTI 



By 

 DAVID GRIFFITHS 



Senior Horticulturist, Office of Horticultural Crops and Diseases 

 Bureau of Plant Industry 



and 



CHARLES HENRY THOMPSON 



Formerly Assistant Botanist, Missouri Botanical Garden 



UNITED STATES 



GOVERNMENT PRINTING OFFICE 



WASHINGTON : 1929 



