the genus rebutia 1895—1981 - Free

Section II Mediolobivia
This series has a very limited distribution occurring only in Argentina in an area
of north Salta and south Jujuy provinces.
Subsection I Setirebutiae. Plants in this section all occur near to the Salta - Jujuy
border around Quebrada del Toro. Rebutia aureiflora var. elegans and related forms
have the most southerly distribution of this group occurring around Quebrada
Escoipe.
Subsection II Cylindrorebutiae. There is probably only a single species which
belongs in this section - R. einsteinii. The myriad of different names appear to refer to
geographical variants. These plants have been found in either Salta or Jujuy
provinces.
Section in Digitorebutia. (Map No. 2)
This section has a very extensive distribution from Salta and Jujuy provinces in
Argentina in the south to the Bolivian departments of Tarija, Chuquisaca, Potosi and
Oruro in the north.
There appear to be several separate centres of distribution where a number of
named species occur in close proximity. It is here suggested that these ‘species’
should be subjected to an intensive ecological investigation to determine whether
these populations are biologically isolated, by pollination vectors and flowering
times. Admittedly members of this series are all self fertile, but their highly coloured
flowers would attract pollinating insects. Gene flow between populations would
occur if the populations which were in close proximity flowered at the same time.
We have determined that there are 5 separate areas of distribution for the
majority of members of this Section.
a) Argentina - Bolivia border areas, Jujuy province.
e.g. R. eos Rausch, R. costata Werd., R. pygmaea (R. E. Fries) Br. & R.
b) Mendez province, Tarija, Bolivia.
e.g. R. brunneoradicata Ritt., R. colorea Ritt.
c) Camargo - Culpina region, Cinti province, Chuquisaca, Bolivia,
e.g. R. diersiana Rausch, R. mixta Ritt.
d) South Chichas province, Potosi, Bolivia,
e.g. R. iridescens Ritt., R. rosalbiflora Ritt.
e) Environs of Potosi City, Potosi, Bolivia.
e.g. R. pygmaea, R. costata f. pilifera Buin. & Donald.
The species found in Oruro also belong here. The proliferation of names which
is particularly true of section III, are at best, geographical variants of very few
species.
Section IV Rebutia (Map No. 3)
Subsection I Rebutiae.
This subsection contains three species complexes. These are R. minuscula, R.
senilis and R. xanthocarpa. The R. minuscula complex includes R. grandiflora
Backbg., R. violaciflora Backbg. and R. kariusiana. The group is totally Argentinian in
distribution ranging from the north Tucuman to Salta and Jujuy provinces. The area is
bounded by Tucuman City, Quebrada Escoipe, Cachipampa and Quebrada del
Toro. R. minuscula occurs throughout this region apparently remaining
14