K.: 



32 



THE CACTACEAE. 



X 



glochids numerous, yellowish, 3 to 4 mm. long; flowers, in only specimen seen, terminal, almost con- 

 tinuous with the stem; ovary tuberculate and spiny like the stem, deeply umbiUcate; seed one, large, 

 flat-winged. 



? ; 



Collected by Walter Fischer in 191 4 in the Province 



Negro 





Dr. Rose during his visit to Argentina in 1915 by Professor Cristobal M. Hicken 

 While this soecies resembles some of the 



species oiCylindropuntia of the United States, 

 the spines are not sheathed. 



Figure 2>2f is from a photograph of the 

 specimen above cited ; figure 34 shows a seed 

 of the same specimen. 



3- Pterocactus pumilus sp. nov. 



Plants low, usually prostrate or ascending; 

 joints cylindric, i cm. in diameter, covered with 

 weak apprcssed spines; areoles very woolly; flower 

 terminal ; ovary sunk in the apex of the terminal 

 joint, somewhat umbilicate; ovules several; seed 

 flattened, 7 mm. in diameter, very thin. 



Collected by Cristobal M. Hicken (No. 

 3286), January 8, 1914, at Puerto Piramides, 

 Chubut, Argentina. 



Figure 35 shows a seed of above speci- 



men. 



4. Pterocactus tuberosus (Pfeiffcr). 



1837. 



Kak- 



Opuniia luhcrosa Pfeifler, Enum. Cact. 146. 

 Pterocactus kuntzei Schumann, Monatsschr. 



teenk. 7: 6. 1897. ' 



Pterocactus kiirtzei Schumann in Engler and Prantl, 



Pflan^enfam. Nachtr. 259. 1897. 

 Pterocactus decipiens Giirke, Monatsschr. Kakteenk. 



17: 147. 1907. 



Roots tubcr-likc, single or in clusters, usually 

 small but sometimes large and thick, up to 12 cm. 

 long by 8 cm. in diameter, deep-seated, giving off 

 several erect stems, these branching at surface of 

 the ground; terminal branches purplish, turgid, 

 3 to 40 cm. long, I cm. in diameter, more or less 

 clavate; areoles numerous, small, bearing numer- 

 ous small white appressed spines; flowers terminal, 

 2 to 3 cm. long; petals long, lanceolate, apiculate, 

 yellow; ovary with numerous areoles bearing long 

 bristles; ovules numerous; fruit dry; seeds large, 

 flat, winged, 10 to i^ mm. in diameter. 



Type locality: Near Mendoza, Argentina. 



Di 



mountains 



We 



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Fig. 37. 



Pterocactus tuberosus. Natural size. Photograph 



by Paul G. Russell. 



Op 



r York 

 from I 



amined cotypes in the Kurtz Herbarium 



to botanists, who have tried to associate it with various opuntias. Dr. Rose, who visited 

 Mendoza in 1915, found a tuberous-rooted cactus in the mountains above that city, which 

 we are convinced is the plant described by Pfeiffer. There is no doubt, on the other 



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