Ovalifolia: Answers to key questions in Budd's Flora and Flora of Alberta leading to this species. 

	plants hairy or downy; NOT [plants almost hairless]
	leaves opposite; NOT [leaves in whorls]
	leaves broader; NOT [leaves linear]
	leaves ovate or lanceolate; NOT [leaves oblong or oval]
	leaves tapering to base; NOT [leaves blunt, rounded or almost cordate at the base]
	flowers purplish or greenish; NOT [flowers rose or red]
	corona hoods each WITH an incurved horn within
	pods LACKING tubercles; NOT [pods with soft tubercles]

Asclepiadaceae: Answers to key questions in Budd's Flora  leading to this family. 

	herbs; NOT [shrubs or trees]
	plants green or with some chlorophyll
	plants WITH milky juice
	flowers not in heads or spikes; NOT [flowers in long or short spikes], NOT [flowers in heads or in form resembling a head]
	corolla regular; NOT [corolla irregular]
	stamens united; NOT [stamens distinct]
	styles distinct; NOT [styles united]
	ovary superior; NOT [ovary inferior]
	pollen grains united into a mass; NOT [pollen grains separate]