i6 
THE CACTACEAE. 
18. Echinocereus subinermis Salm-Dyck in Seemann, Bot. Herald 291. 1856. 
Cereus subinermis Hemslej 7 , Biol. Contr. Amer. Bot. 1: 546. 1880. 
At first simple, 10 to 12 cm. high, afterwards a little branching at base, when young pale green, 
afterwards bluish and finally darker green, erect; ribs 5 to 8, broad, somewhat sinuate; spines all 
radial, small, conic, 1 to 2 mm. long, yellow, 3 or 4, deciduous; flowers large, 5 to 7 cm. long, yellow; 
perianth-segments oblanceolate, acute; spines of areoles on ovary and flower-tube short, white; fruit 
not known. 
Type locality: Near Chihuahua, Mexico. 
Distribution: Northern Mexico. 
This species was introduced into Europe in 1845. It recently flowered in Germany. 
We have studied a plant sent from Berlin to the New York Botanical Garden, in 1902, 
which died before blooming. This plant is the least armed of the genus. 
Illustrations: Bliihende Kakteen 1: pi. 3; Monatsschr. Kakteenk. 26; 99. 
Figure 15 is copied from the first illustration cited above. 
19. Echinocereus luteus Britton and Rose, 
Contr. U. S. Nat. Herb. 16:239. 1913. 
Stem short to elongated,* sometimes 
branching near base, bluish green, more or less 
purplish, 8 or 9-ribbed; ribs rather thin, barely 
undulate, rounded; areoles small, 10 to 12 mm. 
apart; spines small, the radials 6 to 8, unequal, 
2 to 8 mm. long, widely spreading, white with 
darker tips; central spine single, porrect; flowers 
on each rib appearing near top of plant and 
from second or third areole; flower-buds acute, 
reddish, covered with long, brownish bristles; 
areoles on ovary and flower-tube bearing white 
wool and light-colored spines with dark tips; 
flowers pale yellow, delicately sweet-scented, 7 
cm. long, including the ovary; outer perianth- 
segments streaked with red; inner perianth- 
segments lemon-yellow, oblanceolate, acute; 
filaments light yellow. 
Type locality: .Above Alamos, Sonora, 
Mexico. 
Distribution: Western Mexico. 
Illustration: Contr. U. S. Nat. Herb. 
16: pi. 67. 
Figure 16 is from a photograph of the type specimen. 
20 . Echinocereus chloranthus (Engelmann) Rumpler in Forster, Handb. Cact. ed. 2. 814. 1885. 
Cereus chloranthus Engelmann, Proe. Amer. Acad. 3: 278. 1856. 
Cylindric, usually simple, 8 to 15 cm. long, 5 to 7 cm. in diameter; ribs about 13, often nearly 
hidden by the densely set spines; areoles nearly circular; radial spines several, spreading; centrals 
3 or 4, not angled, in a vertical row, one much more elongated than the others, 2 to 3 cm. long; 
flowers yellowish green, 2 cm. long; fruit small, nearly globular, 5 to ro cm. long, dark purplish red, 
covered with small bristly spines; seeds black, dull, pitted, the hilum nearly basal, round. 
Type locality: About FI Paso, Texas. 
Distribution: Western Texas, southeastern New Mexico, and northern Mexico. 
This species is somewhat like Echinocereus viridiflorus, haring similar small flowers. 
It is usually more elongated, with longer central spines and with the flowers appearing 
lower dowm on the plant, generally below the middle. 
Fig. 15.—Echinocereus subinermis. 
*Senor Ortega has sent us an unusual specimen, 2 dm. high, from Mazatlan (exact locality not given.). 
