THE CACTACEAE. 



Fig. I02. — Opuntia lagopus, growing in a mound. 



58. Opuntia australis Weber, Diet. Hort. Bois 

 896. 1898. 



Pterocactus valentinii Spegazzini, Anal. Soc. 

 Cient. Argentina 48: 51. 1899. 



Plants often with large roots, these 5 to 8 cm. 

 long by 2 to 3 cm. in diameter and larger than 

 the parts above ground; joints described as 

 cucumber-shaped, usually 6 to 8 cm. long by i to 

 2 cm. in diameter, but apparently often much 

 smaller, tuberculate; radial spines 10 to 15, 

 spreading, white, short, 3 to 4 cm. long; central 

 spines i or 2, much longer than the radials, 2 

 cm. long, erect, flattened, and somewhat papery; 

 flowers yellow, 2 to 3 cm. broad; seeds said to 

 be rugose. 



Type locality: Between Santa Cruz 

 River and the Strait of Magellan, Argentina. 



Distribution: The southernmost parts of 

 Argentina. 



We have recently examined three col- 

 lections of this plant made by Carl Skotts- 

 berg in the Territory of Santa Cruz, which in 

 the main agree with Weber's description. 

 We have also seen Pterocactus valentinii, 

 which is the same as Skottsberg's plant. 



Dr. Spegazzini records this species as being in Santa Cruz, Argentina ; but as he regards 

 the plant collected there by him as only a variety of O. darwinii, we are inclined to believe 

 he must have collected something else. 



This species, which is found at the Strait of Magellan, extends farther south than any 

 other cactus known to us. 



Fig. 103. — Opuntia australis. Showing large roots, jo 

 and flower. Natural size. 



