A surprising assemblage of genera, with Phryma placed in the Verbenaceae in Michigan Flora and Mimulus and Mazus in the Scrophulariaceae. Evidence for these belonging together in the same family is, however, relatively convincing (Beardsley & Olmstead, 2002).
1. Flowers nearly sessile in pairs in terminal spike-like racemes, subtended by tiny bracts; upper calyx teeth bristle-like; fruit an achene, strongly reflexed.
1. Flowers peduncled (shortly so in Mimulus alatus), borne singly in the axils of opposite leaves or bracts with expanded blades or alternately in few-flowered bracteate racemes; calyx teeth not bristle-like; fruit a capsule; not strongly reflexed.
2. Flowers borne singly in the axils of opposite leaves or bracts; bracts with expanded blades.
2. Flowers borne alternately in few-flowered racemes; bracts linear, often borne on the peduncle slightly above the node.
All species found in Phrymaceae
MICHIGAN FLORA ONLINE. A. A. Reznicek, E. G. Voss, & B. S. Walters. February 2011. University of Michigan. Web. November 21, 2017. http://michiganflora.net/family.aspx?id=PHRYMACEAE.