134 THE CACTACEAfi. 



128. Opuntia sulphurea G. Don in Loudon, Hort. Brit. 196. 1830. 



Opuntia maciilacantha Forster, Handb. Gartenz. 17: 166. 1861. 

 Opuittia pampeana Spegazzini, Contr. Fl. Ventana 30. 1896. 

 Opuntia viilpina Weber, Diet. Hort. Bois 895. 1898. 



Plants low and spreading, forming broad clumps i to 2 meters in diameter, 3 dm. high or less; 

 joints flattened, oblong to obovate, 12 to 25 cm. long, thick, strongly tuberculate, usually green 

 but sometimes purplish; terminal joints easily detached; leaves conic, about 2 mm. long; spines 2 to 

 8, generally straight but sometimes curved and twisted, spreading, 3 to 10 cm. long, brownish to 

 red, but sometimes quite pale at first; flowers about 4 cm. long, yellow; fruit with a deep umbilicus, 

 short, about i cm. long. 



Type locality: Cited as Chile, but doubtless wrong. 



Distribution: Dry parts of western Argentina; recorded also from Chile, and perhaps 

 occurring in Bolivia. 



This species was not seen in Chile by Dr. Rose, and we are doubtful in considering the 

 Bolivian material to be 0. sulfliurca; the joints, as shown by Dr. Rose's specimens, col- 

 lected at La Paz (No. 18860), while thick, are not conspicuously tuberculate; the spines are 

 rather short and stiff, white at first, but somewhat yellowish or horn-colored in age. 



The name Cactus sulplutrcus Gillies was published by G. Don at the place cited above 

 as a synonym of this species. 



Opuntia maculacantha was first described from specimens from Buenos Aires, which 

 had doubtless been sent down from the desert regions to the west or northwest. Schumann 

 in his Monograph referred this species to Mexico, but in his Nachtrag corrects this state- 

 ment. Dr. Weber, with whom we are in agreement, refers the species to O. sitlplinn\t. It 

 is the only species we know with such large tubercles on the joints. 



Several varieties of this species, some of which have been described, are given, such as 

 laevior, major, minor, and fallidior. 



Here probably belongs Opuntia scricca G. Don (Salm-Dyck, Hort. Dyck. 363. 1834), 

 also reported from Chile, but doubtless from Argentina. Cactus sericeus Gillies (Loudon, 

 Hort. Brit. 196. 1830) is the same. There are several varieties of 0. scricea which we would 

 put with it: longispina Salm-Dyck (Hort. Dyck. 363-. 1834); cocrulea Forbes (Hort. Tour 

 Germ. 159. 1837) which is probably 0. coerulea Gillies (Pfeiffer, Enum. Cact. 155. 1837); 

 maelcnii Salm-Dyck (Cact. Hort. Dyck. 1844. 4-6- 1845) which is 0. maelcnii (Salm-Dyck, 

 Cact. Hort. Dyck. 1844. 46. 1845). Opuntia tweediei (Schumann, Gesamtb. Kakteen 745. 

 1898) is given as a synonym of this species by Schumann. Opuntia albisctosa Hildmann, 

 a name only, belongs here according to Hirscht (Monatsschr. Kakteenk. 10: 48. 1900). 



Illustrations: Bluhende Kakteen 3: pi. 136; Monatsschr. Kakteenk. 8:121; Schumann, 

 Gesamtb. Kakteen f. 106, all as Opuntia maculacantha. 



Plate xxiu, figure 2, represents a flowering joint of the plant collected by Dr. Rose 

 near Cordoba, Argentina, in 1915. 



129. Opuntia soehrensii sp. nov. 



Prostrate, in masses usually i meter in diameter or less; joints at first erect or ascending, finally 

 prostrate and rooting and forming new colonies, flattened, rather thin, somewhat tuberculate, very 

 spiny, orbicular, 4 to 6 cm. in diameter, often purplish; spines slender, rather variable in color, 

 usually yellow or brown, several from each areole, sometimes as many as eight, the longest ones 

 5 cm. long, erect; flowers light yellow, 3 cm. long; sepals brown; filaments yellow; style white; 

 stigma-lobes green; fruit naked, 3 cm. long; seeds 3 to 3.5 mm. broad, ovate, thickish, with narrow 

 margin and roughened sides. 



Highlands of southern Peru, Bolivia, and northern Argentina. Type collected by Dr. 

 and Mrs. J. N. Rose below Pampa de Arrieros, Peru, August 23, 1914 (No. 18967). 



This species is very common in its region, but as it is cultivated somewhat for its seeds 

 as well as used as a protection for gardens and yards, its natural distribution is difficult to 

 determine. On the barren hills below La Paz, Bolivia, the species is well established and 



