CACTACEiE. (CACTUS FAMILY.) Ill 



upper ones a little shorter, central ones 1 to 3, bulbous at base, terete, a little 

 stronger, lowest one longest. — Pac. E. Eep. iv. 34, t. 4. S. Colorado and 

 southward. 



5. C. conoideus, Big. Heads 3 to 4 inches high, few from one base, of 

 unequal height, ovate, acutish towurds the apex, conoid : ribs 9 to 11: radial 

 spines 10 to 12, slender, rigid, upper ones 2 to 5 lines long, lateral ones 6 to 

 1 5 lines, upper central spines hardly longer than the lateral ones, lower one 1 to 3 

 inches long, angular and often compressed. — Pac. B. Hep. iv. 36. S. Colorado 

 and southward. 



6. C. paueispiuus, Eng. Stem 5 to 9 inches high, 2 to 3 inches in 

 diameter, ovate-cylindrical, sparingly branching or simple : rifts 5 to 7 : areola; 

 remote: spines strong, 9 to 16 lines long, dark-colored, radial ones 3 to 6, central 

 wanting or rare, stout, subangled. — Pac. B. Bep. iv. 34. S. Colorado and 

 southward. 



4. OPUNTIA, Tourn. 



Petals spreading or rarely erect. Berry succulent or sometimes dry, 

 marked with bristly or spiny areolaj, truncate. — Articulated much-branched 

 plants, of various shapes, low and prostrate, or erect and shrub-like. 



§ 1. Joints compressed: rhaphe forming a prominent bong margin around the seed. 



* Fruit pulpy. 



1. O. Camanehica, Eng. & Big. Large, prostrate, extensively spread- 

 ing : joints ascending, 6 to 7 inches long, suborbiculate : areola? remote, numer- 

 ous, armed : bristles straw-colored or brownish, few : spines 1 to 3, compressed, 

 brownish, paler at the apex, I to 3 inches long, upper Ones elongated, suberect, the 

 others deflexed : berry large, ovate, widely umbiliiate : seeds angled, deeply 

 notched at the hilum. — Pac. B. Eep. iv. 40. S. Colorado and southward. 



2. O. Rafincsquii, Eng. Joints deep green, prostrate, broadly obovate or 

 orbicular: leaves spreading: bristles bright red-brown: spines few and small with 

 a single strong one: flowers sulphur-yellow, mostly with a red centre: berry 

 narrowed at the base, with a funnel-shaped umbilicus. — Pac. K. Bep. iv. 43. 

 Erom Colorado eastward across the plains to Wisconsin and Kentucky. 



Var. (?) fusiformis, Eng. & Big. Roots forming fusiform tubers: bristles 

 stout and yellowish brown : flowers smaller and with fewer sepals : seed 

 larger and thicker. — Pac. B. Bep. iv. 43. From the Missouri southward 

 across the plains. 



* * Fruit dry and prickly. 



3. O. Missouriensis, DC. Prostrate : joints broadly obovate and tuber- 

 culate, 2 to 4 inches long : leaves minute ; their axils armed with a tuft of straw- 

 colored bristles and 5 (o 10 slender radiating spines 1 to 2 inches long: flowers 

 light yellow. — Frequent on the plains and in the mountains, and extending 

 eastward to Wisconsin. 



4. O. rutila, Nutt. Prostrate, with thick obovate or elongated joints, 2 to 4 

 inches long, sometimes thick and almost terete : areola} close, armed with numer- 

 ous slender reddish or gray flexible spines : flowers purple : berry deeply umbili- 

 cate: seeds large, flat, broadly margined, ivory-white. — Torr. & Gray, Fl. i. 

 7 , ",5 S. Wvominsr to Utah and westward. 



