OP ARTS AND SCIENCES. 289 



IV. OPUNTIA, Tourn. 



Ovarium sepalis subulatis caducis axilla pulvilligeris instructum. 

 Semina magna, compressa, discoidea, ssepe marginata, albida. Coty- 

 ledones foliacese, circa albumen curvatfE, plerumque incumbentes. — 

 Plantae articulatse ; articulis complanatis seu teretibus plus minus tu- 

 berculatis ; foliis subulatis caducis axilla pulvillos setosos plerumque 

 aculeiferos gerentibus ; aculeis apice retrorsum hispidis. 



Analysis. 

 I. Petala parva, subulata, suberecta. Subgen. 1. Stenopuntia. 



II. Petala lata, obovata scu obcordata. 



1. Articuli complanati : embryo circa albumen par- 



cum spiraliter convolutus. Subgen. 2. Platopuntia. 



A. Bacca succosa : margo seminum ple- 



rumque angustior {Sarcocarpece). 



a. Glabraj. 



* Bacca parva subglobosa. § 1. Microcarpece. 



* * Articuli magni : aculei 



pauci compressi. § 2. Grandes, 



* * * Articuli minores: acu- 



lei setiformes. § 3. Setispince. 



* * * * Articuli minores : 



aculei pauci, robusti, te- 



retcs. § 4. Vidgares. 



b. Pubescentes. § 5. Pubescentes. 



B. Bacca sicca: margo seminum jDlerum- 



que latissimus. § 6. XerocarpecB. 



2. Articuli cylindracei : embryo circa albumen co- 



piosius subcircularis. Subgen. 3. Ctlindropdntia. 



A. Articuli abbreviati, clavati. § 1- Clavatce. 



B. Articuli cylindracei, elongati. ^ 2. Cylindricce. 



Subgen. 1. Stenopuntia, E. in B. C. E,. Articuli complanati : 

 flores parvi : petala subulata : stigmata pauca. 



1. O. STENOPETALA, E. 1. c. : prostrata ; articulis magnis ; aculeis 

 1-3 cum minoribus 1-3 ancipitibus deflexis atrofuscis ; ovario pul- 

 villis confertis stipato ; sepalis petalisque subulatis suberectis ; stylo 

 inflato ; stigmate simplici. 



On the battle-field of Buena Vista, south of Saltillo. Nearly al- 

 lied to the Mexican 0. grandis, Hort. Angl., which has very simi- 

 lar flowers, but is an erect plant, with few and white spines, and 2 or 

 3 acute stigmata. 



VOL. III. 37 



