84 



THE cactaceae:. 



white, turning brown, persistent on the old stems; flowers yellow, 5 cm. broad; sepals ovate acute, 

 about 5 mm. long; fruit oblong to ovoid, 3 to 4.5 cm. long, its numerous areoles bearmg white glochids 

 and some slender spines; seeds beakless, 5 to 5.5 mm. in diameter, the commissure indistmct, linear. 



Type locality: Near E^l Paso, Texas. 

 Distribution: Western Texas, New Mexico, and 



Mexico 



This species was named for James Duncan 



Graham, Colonel, Corps of Eng 

 Army, who died December 

 Massachusetts. Colonel Graham 



1865, at Boston, 

 was for a time 



chief of the scientific corps of the United States 



and Mexican 



Commission, and caused 



specimens of this plant to be transmitted 



)rge Kngelmann. 

 The plant succeeds rather well in cultivation under glass. 



, — Opuntia 



Xo.75- 



Mex. Bound, pi. 72 ; Schumann, Gesamtb. Kakteen 



Figure 98 1 

 Texas, in 191 3. 



Subgenus 2. TEPHROCACTUS. 



Includes all the South American species of Opuntia which have short, oblong, or globular joints. 

 It is hardly to be distinguished from the North American series Clavatae. Four series are recog- 

 nized. The plants are confined to Peru, Chile, Bolivia, and Argentina. (See key to series, p. 440 



WEBERIANAE 



Plants low, forming dense clumps; joints subcylindric, strongly tuberculate and bearing numer- 



This series suggests Platyopuntia, while the other series show closer relationship with 



ous spines. 



Cylindr opuntia. Only one species known, inhabiting the dry part of northern Argentina. 



1905. 



Densely cespitose, forming clumps 2 to 3 dm. in diameter and 10 to 18 cm. high; joints yellowish 

 green, erect, cylindric, strongly tuberculate, 2 to 6 cm. long, 1.5 to 2 cm. in diameter, densely spiny; 



Fig. 99. — Opuntia weberi as it grows wild. 



■-I- 



