762 TREES OF NORTH AMERICA 



}'-!' thick, covered with a thick epidermis varying from green to purple, and usually 

 developing woody skeletons during their second season, their tubercles prominent, com- 

 pressed, ovoid, \'-\' long. Areolae oval, clothed with pale tomentum and short light brown 

 bristles, their spines 5-15 on the tubercles of young joints and 30-50 on those of older 

 branches, and slender, white to light reddish brown, closely invested in white glistening 

 sheaths, stellate-spreading, \'-\' long, those in the interior sometimes considerably longer 

 than the radial spines. Bark of the trunk and of the larger limbs about {' thick, spineless, 

 nearly black, broken into elongated ridges, and finally much roughened by numerous 

 closely appressed scales. Wood light, soft, pale reddish brown, and conspicuously reticu- 

 late, with conspicuous medullary rays and well defined layers of annual growth; sometimes 

 used in the manufacture of light furniture, canes, picture-frames, and other small articles. 

 Distribution. Widely scattered over the mesas of southern Arizona south of the Colo- 

 rado plateau and of the adjacent regions of Sonora. 



3. Opuntia versicolor Coult. 



Leaves terete, abruptly narrowed to the spinescent apex, \'-\' long, persistent on the 

 branches from four to six weeks. Flowers opening in May, about \\' in diameter, with 

 ovaries f long, broad-ovate acute sepals, and narrow obovate petals rounded above and 

 green tinged with red or with yellow. Fruit usually clavate, 2'-2' long, nearly l' in di- 

 ameter, with areolae generally only above the middle and usually furnished with 1-3 slender 

 reflexed persistent spines about |' long, or occasionally spineless, rarely nearly spherical 

 and only about ' in diameter, ripening from December to February, and at maturity the 

 same color as the joint on which it grows, usually withering, drying, and splitting open 

 on the tree, or remaining fleshy and persistent on the branches until the end of the follow- 

 ing s.ummer, and sometimes through a second winter, or often becoming imbedded in the 

 end of a more or less elongated joint; seeds irregularly angled, with narrow commissures. 



A tree, with an erect trunk occasionally 6-8 high and 8' in diameter, numerous stout 

 irregularly spreading or often upright branches, and cylindric terminal joints generally 



Fig. 685 



6'-12' but sometimes 2 in length, |'-1' in diameter, and covered with a thick dark green 

 or purple epidermis, marked by linear flattened tubercles, their woody skeletons usually 

 formed during their second season. Areolae large, oval, clothed with gray wool, generally 

 bearing a cluster of small bristles, and slender stellate-spreading brown or reddish brown 

 spines, with dose early deciduous straw-colored sheaths, 4-14- and on old tubercles 20-25 in 

 number, the inner 1-4 in number, usually deflexed and unequal in length, the longest about 



