This dark green to purple-brown skinned Rebutia has flowers and fruit that bear similarities to Weingartia (Sulcorebutia), as well as it’s longish areoles which are slightly sunk into the skin, and can be found at higher altitudes than other Rebutia. Nevertheless it’s body structure and seeds point to Rebutia. Regarded by some as synonymous with Rebutia padcayensis beside which it can occur in habitat; found to be distinctive enough to be given specific status by Mosti & Papini (2011).
The description is here.
Plants of this species in the collection include:
Rebutia margarethae HE459a/1
Rebutia margarethae Hoffm. 1927
Rebutia margarethae Hoffm. 2088
Rebutia margarethae RH1361/4
Rebutia margarethae WR523