OPUNTIA. 



131 



and is probably referable to 0. macrorhiza. Through the kindness of Mr. Nelson, we have 

 seen a joint of this species. 



Opuntia bulbosa Hngelmann (Proc. Amer. Acad. 3: 297. 1856) was used by Kngelmann 

 for 0. fusiformis, but never described. 



Opuntia macrorhiza, originally described by Dr. Kngelmann as a species, was afterwards 

 (Proc. Amer. Acad. 3: 296. 1856) proposed as a subspecies but not formally indicated, so 

 that the reference 0. rafinesquei macrorhiza Coulter (Contr. U. S. Nat. Herb. 3: 430. 1896) 

 is the proper designation if it is used as a variety. 



Illustrations: Cact. Mex. Bound, pi. 69; Forster, Handb. Cact. ed. 2. f. 11, 127; Pac. R. 

 Rep. 4: pi. 12, f. 7, 8; pi. 23, f. 6; Suppl. Diet. Card. Nicholson f. 606; W. Watson, Cact. 

 Cult. f. 82, 83 ; Rep. Mo. Bot. Gard. 21 : pi. 20, in part, this last as Opuntia xanthoglochia; 

 Addisonia i : pi. 19. 



Plate XIV, figure 5, represents a 

 flowering joint of the plant collected 

 at Irving, Dallas County, Texas, by 

 Albert Ruth in 1912. 



123. Opuntia plumbea Rose, Smiths. 

 Misc. Coll. 50: 524. 1908. 



Plant low, creeping, 10 cm. high, 20 

 to 30 cm. broad, few jointed; joints small, 

 nearly orbicular, 3 to 5 cm. in diameter, 

 of a dull lead-color, the surface some- 

 what wrinkled in dead specimens ; areoles 

 rather large for the size of the joints; 

 spines pale brownish, slender, usually 

 porrect, often 3 cm. long, mostly 2 in 

 number, rarely as many as 4, sometimes 

 one or even wanting; flowers very small, 

 red; ovary naked; fruit 1.5 to 2 cm. long 

 with a few small areoles and these simply 

 woolly ; seeds small, rather turgid, smooth, 

 and with a shallow obtuse margin. 



Type locality: San Carlos Indian 

 Reservation, Arizona. 



Distribution: Arizona. 



This is a peculiar httle opuntia with very small joints and fruits. 

 from the original collections made by Mr. F. V. Coville in 1904. 



Figure 164 is from a photograph of the type specimen. 



124. Opuntia tortispina Engelmann, Proc. Amer. Acad. 3: 293. 1856. 



Opuntia torlisperma Engelmann, Pac. R. Rep. 4: pi. 23, f. i to 5. 1856. 



Opuntia cymochila Engelmann, Proc. Amer. Acad. 3: 295. 1856. 



Opuntia rafinesquei cymochila Ijngelmann, Proc. Amer. Acad. 3: 295. 1856. 



Opuntia rafinesquei cycmochila montana Engelmann and Bigelow, Pac. R. Rep. 4: 42. 1856. 



Opuntia mesacantha cymochila CouMuT, Contr. V. S. 'Nat. HuTh. y. ^io. 1896. 



Opuntia mesacantha greenei Coulter, Contr. U. S. Nat. Herb. 3: 431. 1896. 



Opuntia mesacantha oplocarpa Coulter, Contr. U. S. Nat. Herb. 3: 431. 1896. 



Opuntia greenei Engelmann in Britton and Rose, Smiths. Misc. Coll. 50: 523. 1908. 



(?) Opuntia sangtiinocula Griflfiths, Proc. Biol. Soc. Washington 27.' 26. 1914. 



Prostrate and creeping; joints ascending, orbicular to obovate, 15 to 20 cm. long; areoles 1.5 to 

 3 cm. apart; spines several, often 6 to 8, the upper and longer ones 3 to 6 cm. long, either white, yel- 

 lowish, or brown; on the upper areoles one spine erect, the others spreading or with the lowermost 

 ones deflexed; flowers sulphur-yellow, 6 to 7.5 cm. broad; fruit rather large, 4 to 5 cm. long, 2 to 3 

 cm. broad; seeds 4 to 6 mm. broad, thick, regular, with a slight indentation at the hilum. 



Type locality: On the Camanchica Plains near the Canadian River. 



Distribution: Wisconsin to South Dakota, Texas, Kansas, Colorado, and New Mexico. 



Fig. 164. — Opuntia plumbea 



It is known only 



