Genus i. 



CACTUS FAMILY. 



569 



I. Echinocereus viridiflorus Engelm. 



Green-flowered Hedgehog Cereus. 



Fig. 2981. 



Echinocereus viridiflorus Engelm. Wisliz. Tour 

 North. Mex. 91. 1848. 



Cereus viridiflorus Engelm. Mem. Am. Acad. (II.) 

 4:50. 1849. 



Stem subglobose to oval-cylindric, i'-8' 

 high, simple, or sparingly branched, 1-2' in 

 diameter. Ribs about 13 ; longer radial spines 

 12-18, with 2-6 setaceous upper ones, the lat- 

 eral ones reddish brown, the others white or 

 rarely purple; central spine stout, straight or 

 curved, purple and white, or wanting; flowers 

 about l' broad, greenish brown without, yel- 

 lowish green within ; petals obtuse or acute ; 

 fruit ellipsoid, greenish, 5"-6" long; seeds 

 tubercled. 



South Dakota to Wyoming, Texas and New 

 Mexico. Our figure is copied from plate 36, 

 Cactaceae of the Mexican Boundary Survey, rep- 

 resenting the Cereus viridiflorus tuhulosus Coult. 

 Contr. Nat. Herb. 3 : 383. 1896. 



2. Echinocereus caespitosus Engelm. & 



Gray. Tufted Hedgehog Cereus. 



Fig. 2982. 



Cereus caespitosus Engelm. & Gray, Bost. Journ. Nat. 

 Hist. 5: 247. 1845. 



Echinocereus caespitosus Engelm. Wisliz. Tour North. 

 Mexico, 110. 1S48. 



Stems ovoid-globose to ovoid-cylindric, usually 

 tufted, sometimes as many as 12 together, some- 

 times single, i'-6' high, i'-4' in diameter; ribs 12 

 or 13; radial spines 20-30, pectinate, white, the 

 lateral ones the longer, 2"-4" long; central spines 

 wanting, or sometimes i or 2 short ones ; flowers 

 rose-purple, 2'-3' broad, fruit ovoid, green, 9"-io" 

 long; seeds tubercled, black, about V long. 



Western Kansas (according to B. B. SmythJ ; 

 Texas and Mexico. 



2. PEDIOCACTUS Britten & Rose. 



Stems globose, leafless, tubercled, the tubercles arranged in spiral rows bearing clusters 

 of spines arising from areolae. Flowers borne on the tubercles, at or near areolae from which 

 spines are developed. Calyx-tube prolonged beyond the ovary, its tube funnelform, bearing a 

 few scales. Petals numerous, similar to the inner sepals, but larger, pinkish. Stamens numer- 

 ous, borne on the tube of the calyx. Ovary green, globose ; style columnar. Berry irregularly 

 bursting, with a terminal scar, nearly or quite scaleless. Seeds tuberqled, with a large sub- 

 basal hilum. [Greek, Plains-cactus.] 



Three species, natives of central and western North America, the following typical. 



