Recent work (Saltonstall et al., 2004) has recognized two different infraspecific taxa based on genetic and morphological analysis: a native subsp. americanus, and the non-native subsp. australis. At this time we believe that the non-native subsp. australis is by far the most common taxon in our area, but the native subsp. americanus has been confirmed from one locality in Suffolk Co., NY. Until further research can clarify the occurrence and distribution of these two taxa, they are herein mapped as one unit.
