218 



THE CACTACEAE. 



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



A low 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 

 under 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 yellow to orange-yellow, only 3 cm. long including the ovary; filaments white; style and 

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



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iPlSp 1 ' 



FIG. 282. Opuntia discolor. 



This species is represented by two collections made by Dr. J. A. Shafer in 1917 which 

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

 Estaro, Argentina, February 23 (type), and No. 

 95, from gravelly hills near Tapia, Tucuman, 

 February 9. 



Apparently common in dry 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 nearly 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. (See page 

 1 13, ante.) 



FIG. 283. Opuntia 

 pestifer. Xo. 5. 



FIG. 284. Opuntia discolor. 



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

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

 tended by 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 0. decumbens; petals lemon-yellow, 2.5 cm. long; stigma-lobes cream-colored. 



Collected by Dr. Glover B. Wilcox in 1909 while acting as surgeon on a ship plying 

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

 ton and flowered there in April 1915. 



Figure 285 represents a joint of the type specimen. 



