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. 
Plants globose to cylindric (ours all erect: and stout), solitary, proliferous or cespi- 
tose, ribbed, 5 to 60 cm. high, usually less than 30 cm.; areoles usually approximate, 
often with the spines overlapping and almost concealing the stem; flowers borne close 
above old spine-bearing areols, 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 8 to 6, the lower one 
about 25 mm. Jong, somewhat reflexed; plants conic at 
the apex........ 2... e eee eee cece eens 1. E. chloranthus. 
Radials short, 2 to 6 mm. long, rigid, pectinate; centrals 
mostly wanting, occasionally a few about 25 mm, long; 
plants depressed at the apex.............0.-2--0---- 2. EL. viridiflorus. 
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.......2. 00... eee eee eee ee eee a eeee 3. L. dasyacanthus, ’ 
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 em. high...............22..2..0002-- 4. E. pectinatus. 
Flowers rose to red; spines variegated red and 
white; plants larger, 10 to 20 cm. high.. 5. E. rigidissimus. 
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.................2--- 6. EE. fendleri. 
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... 7. EH: stramineus. 
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......-..-----.0e0ee ee ee eee 8. E. gonacanthus. 
