This southeastern subaquatic is widespread along shorelines on the Coastal Plain, but it is virtually unknown in the Mississippi Valley north of central La. (K). According to RAB and Cr, the distinctive species has been found in Ky., disjunct from its main range. However, no coll. has been located. Fresh plants are strongly aromatic (lemony) when bruised; corolla is pale to bright blue, 9-13 mm long; calyx is subtended by 2 subulate bractlets; stamens are 4 (W).