THE BABY CACTUS 53 



twenty to twenty-five degrees of frost without injury; with 

 colder winters they must be protected or grown under glass 

 or in conservatories. 



Cream Pincushion Cactus 



(Mamrnillaria Johnstonii) 



(Named for Ivan M. Johnston who collected 

 the plant in Sonora) 



How to identify and how it grows 



The Cream Pincushion Cactus grows from solitary stems 

 having several thick roots, which, however, are not deeply 

 Implanted. In outline the stems are hemispherical or de- 

 pressed globose and have a deep green color. There are 

 many angular tubercles, all spirally arranged, and as many as 

 thirteen white radial spines with brown tips. The central 

 spines are about a half-inch long and red-brown; one is di- 

 rected upward, and the other downward. The flowers are 

 bell-shaped and are formed in a circle about the center of the 

 head, having white margins and pink or pink-tan centers. 

 Like Mammillaria MacDougalii, the tubercles when injured 

 exude a thick white milky fluid. 



How to grow 



Plants may be grown out of doors where temperatures are 

 not lower than twenty or twenty-five degrees below freezing; 

 where the winter weather is colder than this, the plants 

 should be grown in conservatories. They grow from seed 

 in clay loam in pots with enough water to keep the soil moist, 

 preferably with part shade. Large plants transplant quite 

 readily if the roots are not Injured. They grow well In 

 gravelly soil or among rocks and should be watered once a 

 month. 



