1148 



OPUNTIA 



OPUNTIA 



crowded, with fine, gray wool and very numerous golden 

 yellow bristles of unequal length ; spines 3-6, rarely 

 none, on old stems occasionally 40 or more, unequal, 

 angular, golden yellow, deflexed, usually 1 in. or less 

 lonr: fls. yellow, 2-3 in. in diam: fr. deep purple, moder- 



1546. Hedge of Opuntia Tuna. No. 15. 



ately bristly, edible, 1>2 in in diam., broadly obovate to 

 globose; seeds comparatively small, sometimes sterile. 

 Southwest U. S. 



17. pycnacantha, Engelm. An upright, moderately 

 branched plant, 3-5 ft. high: joints oval to orbicular, 

 occasionally somewhat pointed at the ends, 4-8 in. 

 long, sometimes pubescent, armed with a densely inter- 

 woven covering of mostly deflexed spines : areolae 

 crowded, approximately % in. apart, with dark brown 

 wool and numerous long, yellow bristles ; spines 3-7, on 

 old stems 20 or more, straw-colored to ashy, mostly less 

 than 1 in. long: fls. greenish yellow, 2-3 in. broad: fr. 

 obovate, 1% in. in diam. and covered with numerous 

 spines and bristles. Lower Calif. 



18. Engelmannii, Salm. Fig. 1547. An erect to semi- 

 prostrate, profusely branching, coarse plant, 2-5 ft. 

 high, forming large, impenetrable thickets, usually 

 with a short, more or less terete, woody trunk, with 

 grayish bark which becomes unarmed with age: joints 

 broadly obovate to orbicular, pale to bluish green, very 

 variable in size, in large specimens 12-14 in. long and 

 nearly as wide, moderately thick : areolae remote, about 

 1 in. apart, with gray wool and large, rigid, gray to yel- 

 low, unequal bristles ; spines mostly 2-4, sometimes 1-3 

 small additional ones, very variable, horny, variously 

 colored, mostly yellow, or white with reddish base, 

 usually compressed or angular and curved or twisted: 

 fls. yellow, red within, fading to red, 2%-3 in. in diam. : 

 fr. broadly pyriform to globose, frequently 2 in. in 

 diam., dark purple, with insipid purple flesh. U. S. 

 and Mex. This species, with its numerous varieties, is 

 the most widely distributed and abundant of the large, 

 flat-stemmed Opuntias in the United States. It varies 

 greatly in different localities, and its many forms have 

 not as yet been adequately defined. 



19. pheeacantha, Engelm. A diffuse, semi-prostrate 

 plant, 1-2 ft. high, and freely rooting from lower mar- 

 gin of joints: joints broadly obovate, moderately thick, 

 4-6 in. long : areolae about 1 in. apart, with short wool 

 and reddish or brownish bristles ; spines mostly toward 

 margin or on apex of joints, 2-5, straight and stiff, 

 reddish brown to almost black with lighter tips, 1-2 /^ 

 in. long: fls. 2% in. broad, yellow: fr. usually long- 

 pyriform, 1 in. or less in diam. and twice as long, pur- 

 ple, with greenish acid pulp. Southwest U. S. and 

 Mex. This species and a number of the following be- 

 come deep purplish green during autumn and winter. 

 In the spring they lose their purplish color to a large 



extent and take it on again in the fall. The spines are 

 also much darker in winter than in summer. 



20. Camanchica, Engelm. and Begel. A prostrate, 

 widely spreading plant 1-2/4 ft. high, and freely rooting 

 at the lower margin of the joints : joints broadly obovate 

 to orbicular, 4-6 in. long, moderately thick: areolse about 

 1 in. apart, with light brown, short wool and yellowish 

 brown bristles, mostly armed ; spines very variable, 

 usually 1-3, sometimes 3-6, on marginal areolae, reddish 

 to blackish brown with lighter tips, variable in length, 

 sometimes 2% in. long : fls. 2%-3 in. wide, yellow, with 

 reddish center: fr. oval to globose, sometimes pyri- 

 form, deep red, sweet, edible, 1-1% in. in diam. South- 

 west U. S. Var. gigantea of the trade proves to be 

 O. phceacantha, 



21. macrocentra, Engelm. A semi-prostrate, spreading 

 plant, 2-3 ft. high : joints strikingly purple-green, very 

 thin, broadly obovate to nearly orbicular, 5-9 in. in diam., 

 with a few remarkably long spines on the marginal are- 

 olae: areolse about 1 in. apart, with grayish wool and 

 short, grayish yellow bristles; spines rarely wanting, 

 usually 1-2, reddish brown to almost black, annulate 

 3-5 in. long, slender and straight or variously twisted, 

 sometimes 1-3 much smaller, lighter colored, secondary 

 spines: fls. 3 in. wide, yellow: fr. oval to globose, 

 rarely ovate, 1 in. in diam., red ; pulp sweet, edible. 

 Southwestern U. S., Mex. This species is remarkable 

 for its exceedingly long, dark spines and purple joints. 



22. nigricans, Haw. A large, robust, upright plant, 

 2-5 ft. high : joints usually obovate, dark green, rarely 

 tinged with purple, about 10 in. long and 6 in. wide, 

 moderately thick : areolae with short, grayish wool and 

 yellowish brown bristles; spines 1-2, awl-shaped, 1-2 

 in. long, strong, dark brown, at first yellowish : fls. 

 l%-2 in. wide, yellow with red center. Mex. Frequent 

 in cultivation. 



23. filipendula, Engelm. A small, semi-prostrate plant, 

 freely branching from the base of the joints, rarely 10 

 in. high and with thick, tuberous, moniliform roots: 

 joints small and thin, bluish, glaucous, rarely 3 in. in 

 greatest diam., orbicular to broadly obovate, sometimes 

 diamond-shaped, frequently flattened at the top and 

 broader than long: areolae orbicular and with an abun- 

 dance of whitish wool and many long, slender, yellowish 

 green bristles, which are very conspicuous, particularly 

 on the older joints; spines sometimes wanting, when 

 present usually 1-3, rarely more, white, very slender 

 and flexible, 1-2 in. long, mostly marginal: fls. yellow,. 



1547. Opuntia Engelmannii (X%). No. 18. 



l%-2 in. in diam. : fr. clavate to narrowly obovate, 1% 

 in. long and half as wide, greenish yellow, with few 

 seeds. Texas to Ariz., extending into Mexico. 



24. Rafinesquii, Engelm. (O. mesacdntha, Rafin.). A 

 wide-spreading, prostrate plant, freely rooting from the 

 lower margin of the joints, roots sometimes tuberous: 

 joints obovate to orbicular, usually 2-5 in. long and 2-4 



