262, Bureau of Plant Industry , U. S. Dept. of Agricultur 



Plate II. 





Fig. 1.— Mamillaria Compacta, Missouri Botanical Garden, St. Louis, 1911. 



; ._,„..;.-- 



v- A 



mm. 



Fiq. 2.— Mamillaria Pyrrhocephala, Missouri Botanical Garden, St. Louis, 1910. 



