Violaceae

Leaves all cauline, more than 10 and usually entire; sepals without a basal auricle; lower petal notched or 2-lobed at apex and slightly saccate (but not spurred) at base.

Hybanthus

Leaves all basal or fewer than 8 if cauline, toothed to crenulate; sepals with an appendage or auricle extending beyond their attachment at base of flower; lower petal not at all notched, but with a definite spur projecting backward at the base.

Viola

Citation:

MICHIGAN FLORA ONLINE. A. A. Reznicek, E. G. Voss, & B. S. Walters. February 2011. University of Michigan. Web. August 17, 2017. http://michiganflora.net/family.aspx?id=Violaceae.