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

	leaves elliptic to oblong to lanceolate; NOT [leaves linear]
	leaf length-to-width ratio about 6:1; NOT [leaf length-to-width ratio about 12:1]
	leaf margins strongly revolute; NOT [leaves not revolute or only slightly so]
	leaves densely woolly or felty tomentose below; NOT [leaves glaucous, glandular-dotted below] (BF)
	leaves densely rusty-tomentose beneath; NOT [leaves scaly-resinous and pale beneath] (FOA)
	stamens mostly 5-7; NOT [stamens mostly 8-11]

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

	stems erect; NOT [stems prostrate to decumbent or creeping]
	leaves scaly resinous or rusty tomentose below (BF)
	leaves rusty-tomentose or resinous-dotted beneath (FOA)
	flowers in terminal clusters
	petals free; NOT [petals more or less united]
	flowers white
	ovary superior; NOT [ovary inferior]

Ericaceae: Answers to key questions in Budd's Flora  leading to this family. Note that not all the answers apply to all members of Ericaceae found in the Canadian prairie provinces, but they all do apply to this species.  My own notes following some of the answers are in red.

	shrubs or trees; NOT [herbs]
	plants mostly upright; NOT [plants mostly prostrate]
	plants NOT climbing
	stems not armed with prickles
	plants with normal leaves
	leaves alternate; NOT [leaves opposite]
	leaves simple; NOT [leaves compound]
	plants NOT with leathery green leaves (the leaves of L. groenlandicum are somewhat leathery, but are only green on the adaxial surface)
	NOT [inflorescence terminating the branches, half-round or ovoid] (the inflorescence of L. groenlandicum is terminal, but is corymb-shaped rather than half-round or ovoid)
	flowers with two floral rings, and with each petal distinct from the others
	stamens less than 10; NOT [stamens numerous]
	fruit a dry capsule; NOT [fruit a berry], NOT [fruit a 3-lobed drupe]