Dots show county records; shaded area shows likely general distribution.
Computer-generated distribution map, produced in 2003 from records in a database available on this site.
(Note: Monroe County, Florida, includes the southwest portion of the tip of mainland Florida and the upper and lower keys. These three parts of that county are mapped separately in the "dot maps" but not in the computer-generated distribution maps, which are strictly at the county level.)

In 2017, Brandon Woo sent records from three states that expanded the SINA distribution of M. rhombifolium to the north and east: Erie County, PA (2017), Tompkins County, NY (2015), Suffolk County, MA (2017).