170 



THE CACTACEAE. 



185. Opuntia atropes Rose, Smiths. Misc. Coll. 50: 518. 1908. 



Plant i to 3 meters high, much branched; joints oblong to obovate, 20 to 30 cm. long, deep 

 green, softly pubescent; young joints somewhat glossy, leaves 4 to 5 mm. long, acuminate, pubescent, 

 standing almost at right angles to the joints, the tips reddish, areoles circular, filled with short 

 tawny wool; young spines white or yellowish; old spines 3 to 6 cm. long, somewhat angled, standing 

 almost at right angles to the joints, dark yellow or brown at the base, much lighter, often white 

 above; glochids numerous, long, yellow; petals reddish; ovary pubescent, covered with large cushion- 

 like areoles bearing long glochids near the top but with few spines or none, truncate at apex. 



Type locality: Lava beds near Yautepec, Morelos, Mexico. 

 Distribution: Central Mexico. 



186. Opuntia affinis Griffiths, Proc. Biol. Soc. Washington 27: 27. 1914. 



"A low, arborescent species, from 125 cm. high with us at 4 years of age to 2 m. or more in its 

 natural habitat; joints obovate, 13 by 35 cm., broadly rounded above and gradually narrowed below, 

 densely silky, villous to the touch, and villous nature plainly visible when viewed in proper light, 

 slightly raised at areoles, the tubercles being surrounded by a sunken dark-green line; leaves small, 

 subulate, pointed, scarcely 2 mm. in length; areole small, obovate, 3 mm. long, 25 to 30 mm. apart, 

 white to gray; spicules light straw-colored, at first not conspicuous but rather in a connivent tuft, 

 -; mm. long; spines absent below and i to 5 in upper five-sixths of joint, straw-colored, becoming 

 white the second year, the longest 3 cm. and others much shorter, increasing in age in both length 



FIG, 209. Opuntia macdougaliana, Tehuacan. Mexico. 



