150 THE CACTACEAE. 



Echinomastus dasyacanthus about El Paso while we have the true Echinomastus intertextus 

 from Chihuahua. This latter station may be the type locality for this species. 



In making this study we have at last been able to place definitely Cereus pectinatus 

 centralis from near Fort Huachuca, Arizona. This Echinocereus-like plant was described 

 from two sterile specimens whose flowers and fruit were not known. In 1921 J. W. Gidley 

 sent a single specimen from southeastern Arizona. This flowered a few months afterwards, 

 showing clearly that it was not an Echinocereus, but that it belonged to Echinomastus. 

 Further study shows that it is referable to Echinomastus intertextus, although coming from 

 west of the hitherto known range of the species. 



Echinocactus krausei Hildmann (Schumann, Gesamtb. Kakteen 446. 1898) which came 

 from Dragoon Summit, eastern Arizona, may belong here, but Schumann states that the 

 ovary bears spines; it is known to us only from his description. 



Illustrations: Schelle, Handb. Kakteenk. 201. f. 133, as Echinocactus krausei; Forster, 

 Handb. Cact. ed. 2. 561. f. 72; Cact. Mex. Bound, pi. 34; Blanc, Cacti 46. f. 524, as Echino- 

 cactus intertextus. 



Figure 156 is from a photograph of the type specimen of Cereus pectinatus centralis. 



3. Echinomastus dasyacanthus (Engelmann). 



Echinocactus intertextus dasyacanthus Engelmann, Proc. Amer. Acad. 3: 277. 1856. 



Plants cylindric, 10 to 15 cm. high; ribs somewhat spiraled, made up of numerous compressed 

 tubercles; spines slender, more or less purplish; radials 19 to 25, 12 to 22 mm. long; centrals about 4, 

 nearly equal; top of flowering plant and young areoles very woolly; scales and outer perianth-seg- 

 ments red with white margins; inner perianth-segments white or purplish, about 2.5 cm. long, acute 

 or acuminate; ovary bearing a few ovate scales, these naked in their axils; stigma-lobes 9, erect, 

 truncate at apex, deep purple. 



Type locality: Near El Paso, Texas. 



Distribution: Southwestern Texas. 



Most writers, including Engelmann, have treated this species as a variety of Echino- 

 cactus intertextus but in the light of a fuller series of specimens we believe it deserves specific 

 rank. In the past many plants which we now know are true Echinomastus dasyacanthus 

 have been passing as Echinocactus intertextus. 



Besides the difference brought out by Engelmann this species has much larger flowers 

 than Echinomastus intertextus and the inner perianth-segments are acute or acuminate. 

 This species has also a more northern and eastern range. 



Coulter (Contr. U. S. Nat. Herb. 3: 375. 1896) refers to Echinocactus intertextus 

 dasyacanthus, a plant from San Luis Potosi, which we have not seen but which we suspect 

 belongs elsewhere. 



Illustrations: Cact. Mex. Bound, pi. 35, f. 1 to 5, as Echinocactus intertextus dasya- 

 canthus. 



Figure 157 is from a photograph of a plant sent by F. C. Piatt from El Paso, Texas, 

 in 1908. 



4. Echinomastus unguispinus (Engelmann). 



Echinocactus unguispinus Engelmann in Wislizenus, Mem. Tour North. Mex. hi. 1848. 

 Echinocactus trollietii* Rebut, Bait. Cact. Journ. 2: 147. 1895. 



Plants simple, usually globular, sometimes short-cylindric, 10 to 12 cm. high when mature, pale 

 bluish green ; ribs low ; areoles woolly when young, circular ; armament very peculiar, at times almost 

 hiding the plant itself, most of the spines being erect or connivent; radial spines widely spreading, 

 often as many as 25, usually white, except the tips, these darker, the upper ones 2 cm. long, a little 

 longer than the lower; central spines 4 to 8, stouter than the radials, at first reddish or black, but 

 becoming grayish blue in age, the lowermost turned outward and downward and all more or less 

 curved; flowers 2.5 cm. long, reddish. 



*The usual reference to the first publication of this name is the Monatsschrif t fur Kakteenkunde ($', 184. 1895). 

 This appeared, however, in December while the Baltimore Cactus Journal reference appeared in July of the same year. 



