452 CONTEIBUTIONS FEOM THE NATIONAL HEEBAEIUM. 



KEY TO THE SPECIES. 



Some of the spines hooked. 



Central spines 1, hooked, some of the laterals also hooked, 

 slender, terete, about 10 cm. long; plants small, 



about 10 cm. high 1. E. undnatus 



wrightii. 

 Centrals 4, stout, flattened or quadrangular, 5 to 7.5 cm. 

 long (rarely 10 cm.); plants often large, up to 90 

 cm. high and 30 cm. in diameter. 

 Plants small, 10 cm. high or less, 8 cm. or less in di- 

 ameter 2. E. glaucus. 



Plants large, 50 cm. high or over, more than 30 cm. 



in diameter 3. E. wislizeni. 



None of the spines hooked. 



Centrals 2 to 4, not stout; plants small, 10 cm. high or 

 less. 

 Spines flat, flexible, chartaceous; ridges broken into 



tubercles 4 . E. papyracayithus. 



Spines terete, stiff though small; ridges continuous. . 5. E. intertextus. 

 Centrals 1 or none, very stout and horny; plants larger, 

 10 to 25 cm. in diameter. 



< 



Ribs few, 8 to 10, rounded; spines mostly terete; 



plants about 10 cm. in diameter, spheroidal.. . 6. E. horizonthalonius. 



Ribs more numerous, 13 to 21, more acute; spines 

 compressed; plants 20 to 30 cm. in diameter, 

 depressed 7 . E. texensis. 



1. Echinocactus uncinatus ■wrightii Engelm. Proc. Amer. Acad. 3: 277. 1856. 

 Type locality: "Near El Paso and on the river below." 



Range: Southern New Mexico, trans- Pecos Texas, and adjacent Mexico. 



New Mexico: Pena Blanca; Bishops Caj). Lower and Upper Sonoran zones. 



A rare species, known in New Mexico only from the dry foothills in the southern 

 part of the State. It is subcylindric to almost hemispheric, about 10 cm. high and 

 nearly as great in diameter, not including the long, slender, hooked, yellow spines, 

 which are sometimes twice as long as the body of the plant. The ribs are rather 

 prominent, the radials about 8, slender, light-colored; the flowers are small for the 

 genus, about 25 mm. long, of a dull brownish purple and glabrous. 



2. Echinocactus glaucus Schum. Gesamtb. Kakt. 438. 1903. 

 Type locality: Dry Creek, Mesa Grande, Colorado. 



Range: Colorado and Utah to Arizona and northwestern New Mexico. 

 New Mexico: Carrizo Mountains: Shiprock. Dry hills, in the Upper Sonoran 

 Zone. 



3. Echinocatus wislizeni Engelm. in Wisliz. Mem. North. Mex. 96. 1848. 



ViZNAGA. 



Type locality: Near Dona Ana, New Mexico. Type collected by Wislizenus 

 in 1846. 



Range: Utah and Arizona to western Texas and neighboring Mexico. 



New Mexico: Pena Blanca; mesa west of Organ Mountains; Filmore Canyon; 

 Little Florida Mountains. Lower Sonoran Zone. 



The largest cylindric-stemmed cactus found in our range. It is sometimes 70 to 

 90 cm. high and mostly about 40 to 50 cm. in diameter. The spines are numerous; 

 the lowest radials are slender and whitish, the others stouter and rigid, and the 4 

 centrals stout, reddish, banded, the lowest ones sometimes 5 or 6 cm. long, flattened 

 and bony, strongly hooked downward. 



