MINIATURE FORTRESSES 151 



joints, which are as much as six inches long, are club-shaped 

 and tubercled. The spines are very numerous and stout, 

 also very sharp and swordlike, and will cause grief unless 

 one is very careful. They grow a little more than two inches 

 long, are a light yellow, and have short sheaths over their 

 tips. The flowers are about three inches long and are 

 yellow, and the fruit, which is club-shaped and about three 

 inches long, is covered with white cottony hairs and needle- 

 like spicules. These plants grow in the sandy soils of the 

 desert areas of southern New Mexico and southern Arizona 

 and adjacent old Mexico. 



How to grow 



Either prostrate rooted stems or joints planted at any 

 season grow into plants. The seed sown in moist sandy soil 

 grow easily. The plants grow in sandy or gravelly clay 

 soils and should be watered monthly until well established. 

 Temperatures as low as zero do not injure the plants, but 

 with lower temperatures they should be protected. They 

 grow outdoors or indoors. 



Whipple's Cholla (Opuntia Whipplei) 



(Named after Lieutenant Whipple, in charge of the 

 Whipple Expedition of 1853 and 1854) 



How to identify and how it grows 



Whipple's Cholla grows farther north than any other 

 species of Cholla, and reaches three feet in height, composed 

 of several stems that form a low compact clump. The joints 

 are two to ten inches long, are a light green suffused with 

 purple, and are covered with tubercles arranged in spirals. 

 The tan spicules are very short, about an eighth of an inch 

 long and appear in tufts. The two to five spines are a half- 

 inch to an inch long, one of them longer than the others. 



