N 



200 



THE CACTACEAE. 



polyacantha microspcrma and 0. poly 



ifispina, men 



Bailey's Standard 



Cyclopedia of Horticulture (3: 2363. 1916), belong here. 



Optmtia p 



described. 

 Missouri. 



Thomas Nuttall on his memorable 

 i Cactus Jerox, a name which had be 



Willdenow, which led A. H. Ha worth in 1 819 to rename 



poly 



same place Haworth published a second name, OpunUa 



form of 0. po 



Nuttall 



renamed, this time by A. De Candolle, who called it Op 



name it was known for many 

 Haworth's name 



John M 



This species has a wide distribution laterally and altitudinally. 



It is properly a 



mountam 



sometimes 



In a species of such wide distribution and growing 

 circumstances, a wide range of forms is to be expected and a number of 



flowers. 



some of which may 

 ring freely in Tune. 



,J 



Mag 



Exp. Sta. Bull. 78: pl- [3]; Cact. J 



two as Opuntia missouriensis; Pac. R. Rep. 4: pi. 14, f. 8 to 10; pi. 23, f. 18, the last two as 



O; 



Opuntia missouriensis microsper 



Op 



Opuntia missouriensis rufispina; Monatsschr, Kakteenk. 9: 148, this last as 



Opuntia 



figu 



a flowering joint of the plant collected 



A 



by Dr. Rose in western 

 191 2. Figure 247 represents joints 

 of the plant from Colorado, photo- 

 graphed by T. W. Smilhe. 



Series 24- STENOPETALAE. 



This is an anomalous group in 

 Opuntia^ since the flowers are dioeci- 

 ous and the petals are linear and more 

 or less erect. It contains three species 

 which are very different in habit and 

 color of spines, but which were all 

 united into a single species by Profes- 

 sor Schumann. Dr. Engelmann was so 

 much impressed by the peculiar struc- 

 ture of the flowers of this group that he 

 proposed for it a new^ subgenus, Steno- 

 piintia. 



Key to Species. 



Spines dark; plants low, 



prostrate 



Spines white; plants erect. 

 Joints narrow; spines 



acicular 



Joints broader; spines 

 stouter 



225. O. stenopctala 



226. 0. glance scens 



227. 0, grand is 



Fig. 248. — Opuntia stenopetala 



y^ 225. Opuntia stenopetala Engelmann, Proc. Amer. Acad. 3: 289. 1856. 



Low bushy plant, often forming thickets, the main branches procumbent and resting on the 

 edges of the joints; joints obovate to orbicular, i to 2 dm. long, grayish green, but often more or less 



-4 



,ift 



■n 



