The flowers are pink in bud but become blue as they mature, as in some other Boraginaceae.

1. Plant with stiff hairs on calyx, pedicels, leaves, and stems; corolla 10-14 mm long; calyx lobes acute; northwestern Upper Peninsula.

M. paniculata

1. Plant glabrous throughout, glaucous; corolla (14-) 16-22 (-26) mm long; calyx lobes obtuse or nearly so; southern Lower Peninsula (except as escaped from cultivation).

M. virginica