ECHINOCEREUS. 



II 



Text-figure 6 is from a photograph of a plant sent to the New York Botanical Garden 

 by Dr. Rose in 1913, from near Las Vegas, New Mexico; text-figure 7 shows a flowering 

 plant sent to Washington from near Kerrville, Texas, by Mr. B. Mackensen in 191 2. 



Fig. 8. Flower of 



Echinocereus polya- 



canthus. Xo.6. 



Fig. 9. Flowering 



branch of Echinocereus 



pacificus. Xo.G. 



Fig. 10. Flower of 

 Echinocereus neo- 

 mexicanus. Xo.6. 



Fig. 



-Top of joint of Echinocereus 

 conoideus- 



1848. 



9. Echinocereus polyacanthus Engelmann in Wislizenus, Mem. Tour North. Mex. 104. 



Cereus polyacanthus Engelmann in Gray, PI. Fendl. 50. 1849. 

 Cespitose, forming clumps of 20 to 50 stems, pale green but often tinged with red; ribs usually 



10, low; areoles approximate; spines gray when old, at first pale yellow, becoming more or less 

 purplish; radial spines about 12; centrals 4, straight, elongated; flowers crimson, 6 cm. long; spines 

 on ovary and flower-tube yellow, intermixed with cobwebby wool ; fruit and seeds unknown. 



Type locality: Cosihuiriachi, Chihuahua. 



Distribution: Chihuahua and Durango, 

 Mexico, to western New Mexico and south- 

 eastern Arizona. 



Echinocereus polyacanthus was describ- 

 ed by Dr. Engelmann in 1848, based upon 

 specimens collected by Dr. A. Wislizenus at 

 Cosihuiriachi, a small mining town west of 

 the city of Chihuahua. The next year Dr. 

 Engelmann transferred it along with the 

 other species of his genus, Echinocereus, to 

 Cereus, and in 1859, in his report on the 

 Cactaceae of the Mexican Boundary, rede- 

 scribed and illustrated the species; the 

 specimens used by him for this report, 

 however, were largely from Texas and New 

 Mexico, and this additional material repre- 

 sents a quite distinct species. In order to 

 prove this point Dr. Rose in 1908 visited 

 Cosihuiriachi, the type locality, and col- 

 lected living and herbarium specimens 

 which were found to be specifically distinct 

 from the so-called E. polyacanthus from the 



El Paso region which now bears the name E. rosei Wooton and Standley. The habit of the 

 two species is similar, but the armament is somewhat different and the flowers of the true 

 Echinocereus polyacanthus produce an abundance of wool in the axils of the scales which is 



Fig. 12. Echinocereus polyacanthus. 



