Abstract
Areas of endemism (AEs) are fundamental entities of analysis in
biogeography and a key step for biogeographical regionalization. Even
though many studies have contributed to the biogeographical knowledge of
southern USA flora, no endemicity analysis (EA) has been conducted that
would include a large number of native seed plant species from different
families. A new analysis of plant spatial patterns is important as a
first step for a future updated floristic regionalization of North
America North of Mexico. It has become easier to accomplish owing to the
increased availability of large-scale digitized distributional data and
statistical methods of biogeographic analysis. Here we identify the AEs
in SC/SW USA using digitized plant specimen data available from IDigBio.
We built a database with 81,851-specimen point records of 400 selected
mostly angiosperm species and applied the NDM/VNDM method of endemicity
analysis. We then compare the established 26 AEs in the area of study
with the floristic provinces in two comparatively recent regionalization
systems of USA. To understand the spatial patterns, we also pay
attention to the information on relationships of the endemic species
found in phylogenetic literature.