150 



The cactaceae;. 



153. Opuntia brunnescens sp. nov. 



Usually low and prostrate, sometimes i meter high, without a definite trunk, usually forming 

 a bushy clump; joints oblong to orbicular, 15 to 30 cm. long, smooth, dull green, except the purple 

 blotches about the prominent areoles; spines 2 to 5, brownish, porrect or pointing forward, up to 

 4.5 cm. long, stout, sometimes twisted. 



Hills about the city of Cordoba, Argentina, where it was collected by Rose and Russell, 

 September 8, 1915 (No. 21029). 



This species is very common on the dry hills about Cordoba, where it is often associ- 

 ated with Opuntia sulphiirea. It apparently extends northward into Jujuy. 



Figure 187 represents a joint of the type specimen above cited; figure 188 shows its 

 fruit collected by Dr. Shafer (No. 78). 



154. Opuntia galapageia Henslow, Mag. Zool. and Bot. i: 467. 1837. 



Opimtia myriacantha Weber, Diet. Hort. Bois 894. 1898. 



Opuntia helleri Schumann in Robinson, Proc. Amer. Acad. 38: 180. 1902. 



Opuntia insularis Stewart, Proc. Calif. Acad. IV. i: 113. 191 1. 

 Sometimes low and creeping, but often becoming very large, 5 to 10 meters high, with a large top 

 either open or very compact and rounded; trunk at first very spiny and made up of flat joints set 

 end to end, with the short axis of each joint at right angles to that of the adjacent joint, in time 

 becoming terete, and when old nearly naked, 3 to 13 dm. in diameter; bark of old trunks smooth, 

 brown, peeling off in thin layers; joints oblong to orbicular, usually very large, 1.5 to 3.5 dm. long, 

 very spiny; areoles large, often prominent on the trunk, there especially forming knobs bearing 

 numerous spines ; spines extremely variable, but nearl}^ all yellowish brown ; areoles on young, vigorous 

 plants very stout and rigid, very unequal, the longest 7 to 8 cm. long; joints of old plants bearing 

 more or less pungent bristles or sometimes very weak soft hairs instead of spines, while the spines 

 from the trunks often are very stout and sometimes 40 in a cluster; flowers yellow, 7.5 cm. broad; 

 ovary more or less tuberculate ; fruit greenish, sometimes borne in the ends of joints, more or less 

 spiny; seeds large, 5 to 6 mm. broad, white, covered with soft hairs. 



X0.4 



— Fruit of O. brun- 

 nescens. X0.9. 



Fig. 190.- 



-Flower of same. 

 X0.75 



Fig. 189 — Joint of 

 O. galapageia. 



Type locality: Galapagos Islands. 



Distribution: Very common, often forming forests, on the Galapagos Islands. 



We have here combined the four species reported from the Galapagos Islands, while 

 Alban Stewart, in his admirable paper on the botany of these islands, not only recognizes 

 four species, but describes a fifth without specific name. He also has fourteen full-page 



