Until recently the Cape family consisted of three sub-species:
robustus (P.r.r) from South Africa, the nominate species
suahelicus (P.r.s) from central southern Africa
fuscicollis (P.r.f) from south western Africa
Under the new re-classification the nominate robustus is now a separate species from the suahelicus and fuscicollis making the robustus (P.r.r.) the only "true" Cape parrot of the Cape Parrot Family.
The fuscicollis and suahelicus have been reclassified into a new Family, the fuscicollis being the nominate called the Brown-Necked Parrot (P.f.f.) and the suahelicus called the Grey-Headed Parrot (P.f.s.).
It is believed most of the Un-Cape Parrots in the U.S. are from the suahelicus sub-species, fewer being from the nominate fuscicollis. It is also thought there are no robustus, "true" Capes, in the U.S.