OPUNTIA. 



97 



spiny ovary, about 6 cm. long; petals about 3 cm. long, drying reddish or reddish green; areoles of 

 the ovary bearing 5 to 7 spines, which are brown or blackish below and with more or less yellowish 

 tips; fruit not known. 



Collected near Lake Buenos Aires, Territory of Santa Cruz, Argentina, December 12, 

 1908, by Carl Skottsberg (No. 675); and again on the Rio Fenix, north of the locality 

 above given, December 10, 1908 (No. 625, type). 



This species belongs to the subgenus Tephrocactus, but is not closely related to any of 

 the described species. The flower resembles very much the one figured by Henslow 

 as 0. darwinii, and it is possible that he may have had some of this species in his 0. dar- 

 winii; the plant bodies, however, are so different that one could hardly confuse the two. 



Figure 114 is copied from a photograph of the type specimen above cited. 



72. Opuntia nigrispina Schumann, Gesamtb. Kakteen 695. 1898. 



Opunlia purpurea R. E. Fries, Nov. Act. Soc. Sci. Upsal. IV. i': 123. 1905. 



Described as a shrub, i to 2 dm. high and much branched, the branches upright; joints dull 

 green or reddish violet, 2 to 4 cm. long, i to 2 cm. in diameter, oblong-elhpsoid, terete, when young 

 bearing decurrent, spirally arranged tubercles; areoles 2 to 3 mm. in diameter, bearing abundant 



Fig. 114. — Opuntia skottsbergii. Fig. 115. — Opuntia nigrispina. X0.8. 



Fig. 116. — Opuntia pentlandii. X0.4. 



wool and glochids; spines 3 to 5 from upper areoles, 2.5 to 3 cm. long, straight, spreading, subterete, 

 weak, purplish black; flowers small, purple, 2.2 to 2.5 cm. long; petals spatulate, 1.5 cm. long, 6 

 mm. broad; stigma-lobes 5; ovary i cm. long, obovoid, nearly smooth. 



Type locality: On the puna of Humahuaca, Bolivia. 



Distribution: Rare in stony mountains, altitude 3,500 meters, Jujuy, Argentina, and 

 southern Bolivia. 



Figure 115 represents a fruiting joint collected by J. A. Shafer at La Quiaca, Argen- 

 tina, February 2, 1917 (No. 79). 



73. Opuntia pentlandii Salm-Dyck, Allg. Gartenz. 13: 387. 1845. 



Opuntia holiviana Salm-Dyck, Allg. Gartenz. 13: 388. 1845. 



Opuntia pyrrhacantha Schumann, Gesamtb. Kakteen 694. 1898. 



Opuntia dactylifera Vaupel, Bot. Jahrb. Engler Beibl. iii: 29. 1913- 



Opuntia cucumiformis Griffiths, Bull. Torr. Club 43: 524. 1916. (From the description.) 



Plant much branched, forming low, rounded, compact mounds sometimes a meter broad with 

 hundreds of short stubby branches; joints obovoid to oblong-cylindric, plump, 2 to 10 cm. long, 

 sometimes 4 dm. in diameter, more or less pointed, pale green or sometimes purplish, tuberculate; 

 areoles small, circular, filled with short wool and yellow glochids, the upper ones sometimes also 

 having spines; spines sometimes wanting, when present mostly from the upper areoles, erect, 2 to 10, 

 usually bright yellow, sometimes brownish becoming dull brown, the longest one 7 cm. long ; flowers 



