ECHINOCEREUS. 



27 



visor, Mr. Frank Rush, to have living plants sent on to Washington. These arrived in 

 November. Besides several single plants there was a large clump, 3 dm. in diameter, 

 consisting of 25 branches. 



Illustrations: Contr. U. S. Nat. Herb. 12: pi. 56, 57. 



Figure 27 is a copy of the first illustration above cited. 



Fig. 26. Echinocereus reichenbachii. 



Fig. 



-Echinocereus baile} 



35. Echinocereus rigidissimus (Engelmann) Rose, Contr. U. S. Nat. Herb. 12: 293. 1909. 



Cereus pectinatus rigidissimus Engelmann. Proc. Amer. Acad. 3: 279. 1856. 

 Echinocereus pectinatus rigidissimus Rumpler in Forster, Handb. Cact. ed. 2. 818. 

 Echinocereus pectinatus robustus Bauer, Gartenfiora 39: 513. 1890. 



iS8 5 . 



Plants simple, erect, rigid, short-cylindric, 1 to 2 dm. high, 4 to 10 cm. in diameter, usually 

 hidden by the closely set interlocking spines; ribs numerous, 18 to 22, low; areoles approximate, 

 elliptic, 5 to 6 mm. long; radial spines about 16, gray to reddish brown, arranged in horizontal bands, 

 pectinate, rigid, 15 mm. long or less, often recurved; central spines none; flowers purple, 6 to 7 cm. 

 long, fully as broad when expanded; perianth-segments oblong, 3 to 4 cm. long, acute; stamens 

 numerous, shorter than the style ; areoles on ovary somewhat floccose, very spiny ; fruit globular, 3 

 cm. in diameter, very spiny; seeds black, tuberculate, 1.5 mm. in diameter. 



Type locality: Sonora. 



Distribution : Southeastern Arizona and northern Sonora. 



This species is a great favorite in collections, although it does not last long. Its 

 varicolored spines arranged in bands have given it the appropriate name of rainbow cactus, 



