Sort of stretching the subject here; however, at the risk of getting
shot. I'm inclined to agree that the Pacific Coast Irises probably
represent one varied species and the Louisiana species another varied
species. However, I have not studied the populations in the wild, and I
could change my opinion rather easily. To me, if populations are not
genetically isolated from one another, then they are not distinct species.
My understanding is that these two American groups "hybridize" among themselves
rather freely, or in other words they blend where their populations meet.
To me this implies racial status and not species status, or in botany the ranks
of variety or subspecies would be usual.
My specialty is cacti, and the same is true with many cacti. Those
that are popular with collectors in cultivation are split into numerous
micro-species that have little real meaning in natural populations.
However, those that are not popular (for instance Pricklypears) tend to have the
opposite, with clearly distinct "species" lumped wholesale and almost randomly
in the literature, and the true biology of the populations ignored. Iris
seem to follow the first extreme, with too many names for differences that don't
reflect real species distinction. Of course not everyone shares my
definition of what a species should be.