2l8 



THE CACTACEAE. 



96 a. Opuntia discolor sp. nov. (See page 109, ante.) 



Alow plant, forming small dense clumps; joints slender, 4 to 12 cm. long, 1.5 to 2.5 cm. in 

 diameter, turgid, glabrous, dark green with dark purple blotches extending downward from the 

 imder margin of the areoles; spines i to 6, acicular, nearly porrect, somewhat variegated but mostly 

 brown, 3 cm. long or less; glochids tardily developing but conspicuous on old branches, dark brown; 

 flowers light vellow to orange-yellow, only 3 cm. long including the ovarj^; filaments white; style and 

 stigma-lobes nearly white; fruit evidently ven,- small, bright red. 



Fig. 2S2. — Opuntia discolor. 



This species is represented by two collections made by Dr. J. A. Shafer in 191 7 which 

 slightly differ from each other. They are No. iii, from sandy thickets, Santiago del 

 Estaro, Argentina, Februar>^ 23 (type), and No. 

 ~95, from gravelly hills near Tapia, Tucuman, 

 February 9. 



Apparently common in drs' sandy thickets, 

 growing best under bushes where it is least dis- 

 turbed. The joints easily become detached, 

 sticking readily to any disturbing object. 



The species differs from Opuntia retrorsa in its 

 more nearl)^ terete joints and spreading spines. 



Figure 282 is from a photograph of the type 

 plant; figure 284 represents a joint of the plant 

 from near Tapia, Tucuman. 



101 a. Opuntia guatemalensis sp. nov. 

 113, ante.) 



(See page 



Fig. 283. — Opuntia 

 pestifer. Xo. 5. 



Fig. 2S4. — Opuntia discolor. 



Low, spreading plant, resembling 0. decuinbens, but joints glabrous and shining; joints deep 

 green, sometimes with dark blotches below the areoles; areoles small, filled \vith brown wool, sub- 

 tended bv small leaves; spines i to 3 at the areoles, terete, acicular, shining white with blackish tips 

 when young, soon gray, mostly deflexed, somewhat spreading; flower-buds reddish; flowers much 

 smaller than those of O. deciimbens; petals lemon-j^ellow, 2.5 cm. long; stigma-lobes cream-colored. 



Collected b}- Dr. Glover B. Wilcox in 1909 while acting as siu-geon on a ship plying 

 between Guatemala and San Francisco. Living specimens were sent directly to Washing- 

 ton and flowered there in April 191 5. 



Figm-e 285 represents a joint of the type specimen. 



