132 



the; cactaceae. 



This has long remained one of our least-understood species. We believe now that it 

 has a wide range, and that it has been referred heretofore to several species. Opimtia 

 cymochila does not seem to differ from it, and the two published varieties of Opuntia 

 mesacantha, geographically out of harmony with that species, doubtless belong here. 



Opuntia oplocarpa Engelmann (Coulter, Contr. U. S. Nat. Herb. 3: 431. 1896) was 

 published only as a synonym. Opuntia rafinesquei greenei (Cat. Darrah Succ. Manchester 

 58. 1908) is a catalogue name. 



The plant is hardy at New York, flowering profusely, and also at Buck Hill Falls, 

 eastern Pennsylvania. 



Illustrations: Pac. R. Rep. 4: pi. 12, f. i to 3; pi. 23, f. 10 to 12; Rev. Hort. Belg. 40: 

 after 186, all as Opuntia cymochila; Illustr. Fl. 2:1. 2528; ed. 2. 2:f. 2987; Pac. R. Rep. 

 4: pi. 10, f. 3; Stand. Cycl. Hort. Bailey 4:f. 2602, 

 in part, these as Opuntia humifusa. Pac. R. Rep. 4: 

 pi. 8, f. 2, 3; pi. 23, f. I to 5, as 0. tortisperma. Illustr. 

 Fl. 2: f. 2529; ed. 2. 2: f. 2988. 



Plate XV, figure 4, represents a flowering and 

 fruiting joint of a plant from Colorado, grown at the 

 New York Botanical Garden. 



125. Opuntia stenochila Engelmann, Proc. Amer. Acad. 3: 

 296. 1856.* 



Opuntia mesacantha stetiochila Coulter, Contr. U. S. Nat. 

 Herb. 3: 430. 1896. 



Prostrate; joints obovate, 10 cm. long by 7.5 cm. broad; 

 leaves small, 4 to 6 mm. long; spines usually 2, sometimes 

 3, spreading, i long (2.5 to 3 cm. long), and i or 2 short and 

 reflexed, usually light-colored, sometimes nearly white; glo- 

 chids brown; flowers yellow, 6 cm. long; fruit very juicy, 

 4 to 5 cm. long or more, attenuate at base; seeds thick, quite 

 regular, with very narrow obtuse edges. 



Type locality: Canyon of Zuni, New Mexico. 



Distribution: Western New Mexico and Arizona. 



This species has not been well understood. It 

 has usually passed as a variety of the common species 

 of the eastern Mississippi Valley States, but it grows 

 in a very different region. It is the common low, 

 spreading Opuntia of northwestern New Mexico and 

 Arizona. 



Illustrations: Pac. R. Rep. 4: pi. 12, f. 4 to 6; pi. 23, f. 9. 



Figures 165, 166, and 167 are copied from the first illustration above cited. 



126. Opuntia delicata Rose, Contr. U. S. Nat. Herb. 13: 310. 1911. 



A small, procumbent plant with rather thin, ovate, bluish, slightly glaucous joints, often only 4 

 to 9 cm. in diameter; areoles prominent, bearing conspicuous brown glochids; lower areoles spineless, 

 the upper ones bearing i or 2 very slender brownish spines, the longer one 3 to 4 cm. long ; flowers 

 yellow, 5 cm. long, 5 to 6 cm. broad; fruit oblong, spineless, 2 to 3 cm. long; seeds small, about 

 4 mm. in diameter, nearly smooth. 



Type locality: Calabasas, Arizona. 



Distribution: Southeastern Arizona. 



Figure 168 is from a photograph of the type plant. 



Opuntia stenochila, 

 Figs. 165, 166. — Fruits. Fig. 167. — Joint. 



*Although formally published as a species, Engelmann states that it is a form or subspecies, and hence Coulter 

 (Contr. U. S. Nat. Herb. 3: 430. 1896) uses the synonym O. rafinesquei stenochila Engelmann. 



