The jamesii group (nutlets hemispheric, smooth or rugose/tuberculate):
     Oreocarya crassipes (I.M.Johnston) Hasenstab & M.G.Simpson  
     Oreocarya oblata (M.E. Jones) J.F.Macbride  
     Oreocarya palmeri (A.Gray) Greene  
     Oreocarya paysonii J.F.Macbride  
     Oreocarya suffruticosa (Torr.) Greene [& vars.]

The flava group (nutlets compressed, scar closed):
     Oreocarya atwoodii (L.C.Higgins) Hasenstab & M.G.Simpson†  
     Oreocarya capitata Eastwood  
     Oreocarya confertiflora Greene  
     Oreocarya flava A.Nelson  
     Oreocarya johnstonii (L.C.Higgins) Hasenstab & M.G.Simpson  
     Oreocarya leucophaea (Douglas) Greene  
     Oreocarya salmonensis A.Nelson & J.F.Macbride  
     Oreocarya semiglabra (Barneby) Hasenstab & M.G.Simpson  

The stricta group (stout, hispid stems; nutlet ventral surface smooth):
     Oreocarya barnebyi (I.M.Johnston) Hasenstab & M.G.Simpson  
     Oreocarya stricta Osterh.  

The nubigena group (nutlets lance-ovate, ventrally smooth, dorsally rough):
     Oreocarya crymophila (I.M.Johnston) Jeps. & Hoover  
     Oreocarya hypsophila (I.M.Johnston) Hasenstab & M.G.Simpson  
     Oreocarya nubigena Greene  
     Oreocarya schoolcraftii (Tiehm) R.B. Kelley  
     Oreocarya subretusa (I.M.Johnston) Abrams  
     
The abata group (nutlets rugose or tuberculate; ventral scar open, triangular, with elevated margin):
     Oreocarya depressa (M.E. Jones) J.F.Macbride  
     Oreocarya hoffmannii (I.M.Johnston) Abrams  
     Oreocarya tumulosa Payson  
     Oreocarya virginensis (M.E. Jones) J.F.Macbride  
     Oreocarya welshii (K.H.Thorne & L.C.Higgins) R.B. Kelley **

The caespitosa group (hummock forming vs. gypsophilous):
     Oreocarya caespitosa A.Nelson  
     Oreocarya ochroleuca (L.C.Higgins) R.B. Kelley  

The humilis group (nutlets muricate, scar open, basally triangular):
     Oreocarya breviflora Osterh.  
     Oreocarya cana A.Nelson  
     Oreocarya compacta (L.C.Higgins) R.B.Kelley  
     Oreocarya fulvocanescens (S.Watson) Greene [& vars.]
     Oreocarya humilis (A.Gray) Greene [& subspp.]
     Oreocarya jonesiana Payson  
     Oreocarya propria A.Nelson & J.F.Macbride  
     Oreocarya roosiorum (Munz) R.B. Kelley, Hasenstab, & M.G.Simpson  

The elata group (corolla tube < calyx [except O. rollinsii] nutlets dorsally roughened, rugose and/or tuberculate/muricate, ventrally smooth or rough; scar straight, margins not elevated):
     Oreocarya aperta Eastwood  
     Oreocarya elata Eastwood  
     Oreocarya glomerata (Pursh) Greene
     Oreocarya grahamii (I.M.Johnston) R.B. Kelley
     Oreocarya interrupta Greene  
     Oreocarya rollinsii (I.M.Johnston) W.A. Weber  
     Oreocarya rugulosa Payson  
     Oreocarya shackletteana (L.C.Higgins) R.B. Kelley  
     Oreocarya sobolifera (Payson) R.B. Kelley  
     Oreocarya spiculifera Piper  
     Oreocarya thompsonii (I.M.Johnston) Abrams  
     Oreocarya thyrsiflora Greene  
     Oreocarya weberi (I.M.Johnston) W.A. Weber  

The flavoculata group (nutlets rugose and tuberculate or muricate or foveolate; scar slightly open [except O. bakeri], constricted above base, margin usu. elevated):
     Oreocarya bakeri Greene  
     Oreocarya flavoculata A.Nelson  
     Oreocarya longiflora A.Nelson  
     Oreocarya mensana (M. E. Jones) Payson  
     Oreocarya osterhoutii Payson  
     Oreocarya paradoxa A.Nelson  
     Oreocarya tenuis Eastwood  
     Oreocarya wetherillii Eastwood  

The virgata group (stem stout, fistulose; inflorescene spicate with elongated foliar bracts):
     Oreocarya virgata (Porter) Greene  

The setosissima group (stem simple, erect; nutlets broadly winged; calyx segments ovate):
     Oreocarya setosissima (A.Gray) Greene  




Unplaced to date:
     Oreocarya creutzfeldtii (S.L. Welsh) R.B.Kelley  
     Oreocarya revealii W.A. Weber & R.C. Wittmann  
     Oreocarya sericea Greene  [treated by Higgins 1971, but not placed]
     Oreocarya subcapitata (Dorn & Lichvar) R.B. Kelley