300 PROCEEDINGS OF THE AMERICAN ACADEMY 



Vai'. a. RUFISPINA, E. & B. : articulis orbiculatis ; aculeis interiori- 

 bus 3-5 validis fuscis ; bacca ovata. 



Var. ^. PLATYCARPA, E. : articulis obovato-orbiculatis ; aculeis in- 

 terioribus subsingulis validis fuscis ; bacca depresso-globosa late um- 

 bilicata. 



Var. y. MiCROSPERMA, E. : articulis aculeisque prcecedentis ; bacca 

 ovata breviter aculeolata ; seminibus minoribus anguste marginatis. 



Var. S. suBiNERMis, E. : articulis elongato-obovatis, pulvillis sub- 

 remotis inferioribus inermibus, superioribus aculeos paucos breves 

 gerentibus. 



Var. e. ALBisPiNA, E. & B. : articulis late obovatis ; aculeis 6-12 

 omnibus albis gracilioribus ; bacca ovata. 



Var. C- TRicHOPHORA, E. & B. : articulis ovatis ; pulvillis confertis ; 

 aculeis 10-18 setiformibus (in articulis vetustis numerosioribus) capil- 

 laceis flexuosis ; bacca ovata ; seminibus maximis. 



From the Upper Missouri to the Canadian ; principally occupying 

 the western plains, but also on the mountains towards Santa Fe and 

 west of it. — The last-mentioned variety (which I would consider 

 a distinct species, were it not for the var. albispina, which seems to 

 unite it with the others) has been found only on the mountains near 

 Albuquerque : all the other forms occur on the Upper Missouri, and 

 a. and e. also on the Canadian. Other and intermediate forms of this 

 variable but nevertheless well-characterized species will no doubt be 

 found in the wide territory inhabited by it. It flowers in May and 

 June. — Joints 2-4, rarely 4-6 inches long, and 2 - 3| inches wide, 

 light green ; leaves 1J--2 lines long; larger spines 1 - 1|-, rarely 2 

 inches long, in S. not more than 3-6 lines long. Flowers 2-3 

 inches in diameter, with short green stigmata forming a compact 

 head. Fruit 1-1^ inches long, with shorter or longer spines, and a 

 rather shallow umbilicus. Var. /S. has a remarkably large flat fruit. 

 Seed generally about 3 lines, but in y. only 2 lines, in diameter. 



24. O. SPH^ROCARPA, E. & B. 1. c. : diffusa ; articulis orbiculatis 

 tuberculatis ; pulvillis confertis stramineo-setosis plerisque inermibus, 

 summis solum aculeos 1-2 deflexos patulosve majores gerentibus, 

 adjectis ssepe 1-3 brevioribus ; bacca globosa vix aculeolata ; semi- 

 nibus mediis. 



Mountains near Albuquerque, New Mexico. — Joints 3 inches in 

 diameter, strongly tuberculated ; pulvilli 4 or 5 lines apart ; spines 

 6-12 lines long, reddish-brown, often single or 2 or 3 together, with 



