308 PROCEEDINGS OF THE AMERICAN ACADEMY 



From north and east of Santa Fe and the Llano Estacado, to Zuni ; 

 extending southward deep into Mexico : fl. May - July. — Northward 

 5-6, south 10-20 or more, feet high ; easily characterized by the 

 horizontal and verticillate branches, etc. 



43. O. ACANTHOCARPA, E. & B. in P. R. R. : arborescens; ramis 

 alternis adscendentibus ; articulis cylindricis ; tuberculis elongatis ; 

 aculeis 8-25 stellato-divaricatis ; bacca subglobosa tuberculata acu- 

 leata ; seminibus multangulatis. 



Mountains of Cactus Pass, between Santa Fe and the Western Col- 

 orado. — Stems 5-6 feet high ; branches few, alternate, and separat- 

 ing from the stem at an acute angle. Joints (as in the preceding) 

 4 - 6 or 8 inches long, about 1 inch in diameter ; tubercles 9-10 lines 

 long ; interior spines 1 - 1:|- inches, exterior ones 4-10 lines, long. 

 Spines of fruit on the depressed tubercles 3-6 lines long. Seeds 

 large, unlike those of any other Opuntia seen by me. 



44. O. MAMiLLATA, A. Scliott in litt., B. C. R. : arborescens, divari- 

 cato-ramosissima ; articulis crassis abbreviatis perviridibus ; tuberculis 

 tumidis ; aculeis 4-6 brevibus plerisque deflexis ; flore parvo purpu- 

 reo ; bacca obovata inermi ; seminibus parvis. 



Sonora, on the Sierra Babuquibari, in fertile soil : fl. July and Au- 

 gust. — Stems 5-6 feet high ; joints 3-4 inches long, 14- inches in 

 diameter; the swelling tubercles very prominent; spines 3-9 lines 

 long, sometimes almost wanting. Flowers an inch or less in diameter. 



45. O. Thurberi, E. in B. C. R. : frutescens, erecta ; articulis cylin- 

 dricis gracilibus elongato-tuberculatis ; aculeis 3-5 brevibus diver- 

 gento-deflexis ; flore miniato. 



Bacuachi, Sonora : fl. June. — Much moz'e slender than any spe- 

 cies yet enumerated in this subgenus. Joints ^ inch in diameter ; 

 tubercles 9 lines long ; spines 3-8 lines long, the lowest one the 

 stoutest. Flower 1| inches in diameter. 



* * Monacanthce : lignum densum : articuli graciliores obscure tu- 

 berculati : aculei singuli : flores flavi seu rubri ; semina plus minus 

 marginata. 



46. O. Wrightii, E. 1. c. : frutescens, erecta ; articulis cylindricis 

 gracilibus elongato-subtuberculatis ; aculeis subsingulis porrectis vel 

 subdeflexis ; flore miniato. 



On steep mountain-sides, from the Limpio to the Pecos, and in 

 Northern Mexico : fl. June and July. — Shrub 2-4 feet high, 1-1^ 



