i6 



THE CACTACEAE. 



18. Echinocereus subinermis Salm-Dyck in Seemann, Bot. Herald 291. 1856. 



Cereus subinermis Hemsley, Biol. Contr. Amer. Bot. 1: 546. 1880. 



At first simple, 10 to 12 em. 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. 



Fig. 15. Echinocerc 



Figure 16 is from a photograph of the type specimen. 



1885. 



20. Echinocereus chloranthus (Engelmann) Riimpler in Forster, Handb. Cact. ed. 2. 814. 

 Cereus chloranthus Engelmann, Proc. 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 10 cm. long, dark purplish red, 

 covered with small bristly spines; seeds black, dull, pitted, the hilum nearly basal, round. 



Type locality: About El Paso, Texas. 



Distribution: Western Texas, southeastern New Mexico, and northern Mexico. 



This species is somewhat like Echinocereus viriJiflorus, having similar small flowers. 

 It is usually more elongated, with longer central spines and with the flowers appearing 

 lower down on the plant, generally below the middle. 





*Senor Ortega has sent us an unusual specimen, 2 dm. high, from Mazatlan (exact locality not given). 



