io4 



THE CACTACEAE. 



5.5. cm. long; ovary and flower-tube bearing lanceolate acute scales, these without hairs in their 



axils 





" 



Type locality: Above Balsas in the department of Amazonas, Peru. 

 Distribution: Northeastern Peru. 



Through the kindness of F. Vaupel we have been able to study a fragment of this very 

 interesting species. It much resembles Matucana haynei. 



12. HAM ATOC ACTUS gen. nov. 



Globose to short-cylindric, of flabby texture like an Echinocereus, distinctly ribbed, the ribs 

 more or less spiraled; areoles circular; spines radial and central, one of them usually hooked; flower- 

 bud pointed, covered with imbricating scales ; flower-tube narrow, funnelform ; limb broad ; scales 

 on the ovary few, fugacious, small, naked in their axils; fruit small, globular, red, dehiscing by a 

 basal pore ; seeds black, tuberculate; hilum large, basal, circular; embryo straight; cotyledons short 

 and thick. 



Echinocactus setispinus Engehnann, the only species here recognized, is the type. 



Although this plant heretofore always passed as an Echinocactus its anomalous charac- 

 ters have been, recognized, such as the texture of the fleshy stem, the fruit, and the seeds ; 

 Engelmann in his. Synopsis of the Cactaceae thus spoke of it: "The compressed ribs, 

 setaceous spines, small red berry, and tuberculated seeds easily distinguish it from all its 

 allies." 



The generic name is from hamatus hooked, and cactus, referring to the hooked central 

 spine. 



Figs. 1 10 and 1 1 1 . Fruit and flower of 

 Hamatocactus setispinus. X0.8. 



Fig. 



-Hamatocactus setispinus. 



1. Hamatocactus setispinus (Engelmann). 



Echinocactus setispinus Engelmann, Bost. Journ. Nat. Hist. 5: 246. 1845. 

 Echinocactus muehlenpfordlii Fennel, Allg. Gartenz. 15: 65. 1847. 

 Echinocactus hamatus Muhlenpfordt, Allg. Gartenz. 16: 18. 1848. Not Forbes, 1837. 

 Echinocactns setispinus hamatus Engelmann, Bost. Journ. Nat. Hist. 6: 201. 1850. 

 Echinocactus setispinus setaceus Engelmann, Bost. Journ. Nat. Hist. 6: 201. 1850. 

 Echinocactus setispinus cachetianus Labouret, Monogr. Cact. 203. 1853. 

 Echinocactus hamulosus Regel, Ind. Sem. Hort. Petrop. 34. 1856. 



