Minnesota Plant Life. 331 



in groups of from one to four. The flowers are yellow with 

 a red centre. The other two prickly-pears have smaller fruits, 

 covered with s]:)ines and drier in texture. The many-spined 

 prickly-pear bears on the flattened stems little masses of bristles 

 in tufts, with from five to twelve spines in a group. They are 

 slender, from half an inch to two inches in length. The brittle 

 prickly-pear produces, on the more egg-shaped joints of the 

 stem, from one to four central spines, varying from a half to 

 one and a half inches in length. Each group of central spines 

 is surrounded by from four to six lateral shorter prongs. The 

 spines in this species are gray, becoming black toward the tips, 

 while in the many-spined prickly-pear the thorns are whitish 

 and not black toward the tips. 



The purple cactus is known by its almost globular, warty 

 and thorn-covered stem, from one to five inches in height, 

 arising either singly or in tufts. The flowers are terminal and 

 solitary, and are purple or purplish-red. This species is re- 

 ported only from the vicinity of Ortonville, and probably does 

 not o-row elsewhere in the state. 



