454 



CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 



or more acute ridges. The spines are few, 6 to 9 in the areole, stout, straight or some- 

 what curved, compressed, bony or horny, reddish, with a single recurved central, 

 this not hooked. The flowers are moderately large, about 5 cm. long, bright pink, 

 fading as they grow older, white-woolly outside. They are followed by a pulpy, 

 bright red fruit which persists for some time, unless eaten by birds or small rodents. 



4. ECHINOCEREUS Engelm. 



riant s globose to cylindric (ours all erect and stout), solitary, proliferous or cespi- 

 to e, ribbed, 5 to GO cm. high, usually less than 30 cm.; areoles usually approximate, 

 often with I he spines overlapping and almost concealing the stem; flowers borne close 

 above old spine-bearing areolae, thus lateral on the stem; ovary spiny but the spines 

 deciduous from the ripe fruit; fruit succulent, with thin rind, edible, with a pleasant 

 flavor in most species; seeds small, numerous. 



KEY TO THE SPECIES. 



Flowers small, about 2 cm. long, green; spines reddish and white. 

 Radial spines long, 5 to 10 mm. ; centrals 3- to 6, the lower one 

 about 25 mm. long, somewhat reflexed; plants conic at 



the apex 1. 



Radials short, 2 to 6 mm. long, rigid, pectinate; centrals 

 mostly wanting, occasionally a few about 25 mm. long; 



plants depressed at the apex 2. 



Flowers larger, 3 to 10 cm. long, not green; spines variously 

 colored. 

 Flowers bright yellow, large, about 10 cm. long, closing at 

 night; spines short, pectinate, more or less tinged with 



pink 



Flowers never yellow; flowers and spines various. 



Flowers large, 7 to 10 cm. long, open only in daylight, 

 purple or rose, never scarlet; petals mostly acute. 

 Spines short, rigid, pectinate; centrals mostly want- 

 ing; flowers purple to rose. 

 Flowers purple; spines white; plants small, 5 to 



8 cm. high 4 



Flowers rose to red; spines variegated red and 



white; plants larger, 10 to 20 cm. high.. 5 

 Spines longer, not pectinate; centrals long and con- 

 spicuous; flowers purple. 

 Spines dark, comparatively few, the upper cen- 

 trals connivent-curved ; stems only a few 



together or solitary 6 



Spines pale yellow to straw-colored, very num- 

 erous and long; young spines straight, 

 dusky; plants usually forming large 

 mounds, often a meter across or more. 

 Flowers of medium size, 3 to 7 cm. long (rarely a little 

 larger), open day and night, bright scarlet, orange 

 scarlet, or cardinal, never purple; petals mostly 

 obtuse. 

 Spines very stout, strongly angled, relatively few in 

 the areole. 

 Spines 6 to 8, mostly 6, twisted and curved; 

 radials 2 to 3 cm. long; centrals 4 cm. 

 long or more 8. E. gonacanthus. 



E. chloranthus. 



E. vlrldijtorus. 



3. E. dasyacanthus . 



E. pectinatus. 

 E. riyidissimus. 



E. fendleri. 

 7. E. stramineus. 



