42 THE CACTACEAE. 
This species was named for Karl Ehrenberg who spent ten years in Mexico, where he 
made large collections of cacti. 
E. ehrenbergu cristatus (Forster, Handb. Cact. ed. 2. 776. 1885) is a garden monstrosity. 
2 60. Echinocereus longisetus (Engelmann) Riimpler in Forster, Handb. Cact. ed. 2. 822. 1885. 
Cereus longisetus Engelmann, Proc. Amer. Acad. 3: 280. 1856. , 
Plants simple or nearly so, cylindric, 15 to 25 cm. long, 5 to 7.5 cm. in diameter; ribs 11 to 14, 
somewhat tubercled; areoles circular; spines slender, elongated, white; radial spines 18 to 20, spread- 
ing, the lower 10 to 15 mm. long, much longer than the upper; central spines 5 to 7, very unequal, the 
lower elongated, 2.5 to 5.5 cm. long, deflexed; flowers said to be red. 
Fic. 54.—Echinocereus mamillatus. 
Fic. 55 a.—Echinocereus sp. 
Fic. 55.—Echinocereus longisetus. 
Type locality: Santa Rosa, south of the Rio Grande in Coahuila. 
Distribution: Coahuila. _ 
This plant, although collected as long ago as 1853 and well illustrated, has not been 
rediscovered ; neither flowers nor fruit were collected and these are still desiderata; when ob- 
tained the relationship of this evidently distinct species can be determined. 
Illustration: Cact. Mex. Bound. pl. 45, as Cereus longisetus. 
Figure 55 is a copy of the illustration above cited. 
