Dilatata: Answers to key questions in Lilies, Irises & Orchids of Saskatchewan by Vernon L. Harms and Anna L. Leighton leading to this species. The answers are in the order you would normally work through the key.

	Leaves 3 or more, cauline, gradually reduced to bracts upwards;  NOT [Leaves 1-2, basal; scape bractless or with 1-6 bracts]
	Flowers bright white; lip conspicuously widened at base; viscidia linear to linear-oblong or linear-oblanceolate; NOT [Flowers yellowish-green to whitish-green; lip not conspicuously widened at base; viscidia oblong to orbicular]

Platanthera: Answers to key questions in Lilies, Irises & Orchids of Saskatchewan by Vernon L. Harms and Anna L. Leighton leading to this genus. The answers are in the order you would normally work through the key. 

	Plants green, with at least some green leaf-blades, these sometimes early withering or late developing; flowering stems green (pale pink to purplish-red in Calypso bulbosa), bearing sheathing bracts in some species; rootstocks not coral-like; capsules spreading to erect (occasionally drooping when old); NOT [Plants non-green saprophytes lacking leaf-blades; flowering stems yellowish to purplish-red or brown (pale greenish-yellow in C. trifid), bearing sheathing bracts; rhizomes rootless, coral-like in their branching; capsules drooping]
	Flowers 3 or more in a spike-like inflorescence, small, often inconspicuous; lip usually less than 1 cm long, but if longer, neither inflated nor broad and flat; NOT [Flowers 1 to 2 per stalk (occasionally more in Cypripedium reginae and C. montanum), large, showy; lip 1 cm long or longer, either inflated or broad and flat]
	Lip spurred (spur short and bag-like in Coeloglossum  viride); NOT [Lip not spurred]
	Lip yellowish-green (often tinged with red  in Coeloglossum) or white, unmarked, narrower, tongue- or strap-shaped, lacking lateral  lobes; flower stems leafy (except in Platanthera obtusata which has a single leaf at base of stem, and Platanthera orbiculata, which has two leaves, both basal) arising from clusters of thick roots; NOT [Lip white with roseate spots, ovate in outline with a pair of protruding lateral lobes near base; terminal lobe flared and usually notched; flower stems naked with a single leaf present at base of stalk and arising from rhizomes with slender roots]
	Lip not toothed at tip, about the same length as spur; stems leafy or leafless; floral bracts shorter; flowers greenish, greenish-white, or white; clusters of roots not palmately arranged; NOT [Lip 2 (3)-toothed at tip, much longer than the inconspicuous pouch-like spur; stems with up to 5  leaves; floral bracts prominent throughout inflorescence, elongated to 2-4 times flower length on raceme lower portions; flowers greenish to yellowish-green; clusters of roots palmately-arranged]

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

	plants NOT aquatic
	flowers irregular; NOT [flowers regular]
	perianth present, conspicuous, in two series of 3 segments, often brightly colored; NOT [perianth absent or inconspicuous]
	perianth usually large, consisting of sepals and petals usually alike, variously colored; NOT [perianth small, consisting of 3 green sepals and 3 whitish petals]
	petals NOT deciduous
	stamens 1 or 2; NOT [stamens 3 or 6]