594 PATAGONIAN EXPEDITIONS I BOTANY. 



Petals numerous, slightly united at the base. Stamens very numer- 

 ous, in several series. Ovary cylindric, exserted, becoming a pyriform 

 berry. 



Species 150, chiefly from Mexico to Chili; a few in the United States. 

 Some have been introduced into the Old World, and run wild. (Fig. in 

 Eng. & Prantl, iii, 6a, p. 170, C, G, and 201.) O. opuntia (L.) Coult, 

 (O. vulgaris Mill.) of American origin is now spreading over the tropical 

 parts of the Old World. Its fleshy fruit is edible. 



i. OPUNTIA DARWINII Hensl. 



Prostrate, branching shrub, about 5 cm. high, olivaceous. Joints egg- 

 form, scarcely tuberculate. Spines, especially when young, entire (not 

 trifid). Flowers on top of the uppermost joint, yellow. 



Patagon., by Rio Negro; Rio Chubut; Puerto Deseado ; in gravelly 

 deserts near Rio Chico. 



2. O. PATAGONICA Phil. 



Joints subclavate, bright green. Cushions covered by a short, white 

 tomentum. Spines whitish, i compressed, 26 mm. long, and 2 only 1.3 

 mm. long. Leaves 3 mm. long. 



Patagon. 



3. O. PENICILLIGERA Speg. 



Platyopuntia. Armed, low, subprostrate.. Joints orbicular or broad- 

 obovate, dull green, plane or slightly convex. Areoles not umbonate, 

 rather lax, usually with whitish slender torted spines, the central one 

 long, and i or 2 laterals shorter and weaker ; rarely none ; when old re- 

 trorsely appressed ; with large and rather long pencils of rusty glochidia. 

 Flowers lemon-colored. Fruit clavate, green to rufous. 



N. Patagon., between Rio Negro and Rio Colorado ; Bahia Blanca and 

 Neuquen. 



. 4- O. PLATYACANTHA S. Dick. 



Low, branching ; the branches divaricate, cylindrical, not very tubercu- 

 late, shining brown. Cushions large, immersed, fulvescent, with seta- 

 ceous tomentum, and with diversely-formed spines. Lowest spines 3-4, 

 slender, white appressed. Upper ones 23, longer, reed-like, gray. 



(Chili); Patagon., Chubut. 



