From Flora of Indiana (1940) by Charles C. Deam

Infrequent in the lake area where it is found on the low borders of lakes or on interdunal flats. It grows in moist, sandy or gravelly places and on marshy shores.

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Indiana Coefficient of Conservatism: C = 7 (both varieties as recognized by Deam)

Wetland Indicator Status: OBL (both varieties)

Diagnostic Traits: Leaves opposite, linear; pedicels shorter than the calyx; calyx lobes 1.2-4 mm; longest corollas less than 2 cm.

Treated as a subspecies of A. purpurea in the Michigan Flora.