Moosomin Regional Park
Note that one of the petals is folded widthwise, obscuring the stamens and pistil from view. There is a fringed crest along the fold line.
The key in Budd's Flora leading to family Polygalaceae is unsatisfactory. It requires "calyx regular", whereas the calyx of this species is highly irregular. It also requires "each petal distinct from the others", whereas all the petals of this species are connected to each other.
Senega: Answers to key questions in Budd's Flora and Flora of Alberta leading to this species.
Polygalaceae: Answers to key questions in Budd's Flora leading to this family.