Angustifolium: Answers to key questions in Rushes, Bulrushes & Pondweeds plus the remaining Monocots of Saskatchewan by V. L. Harms, A. L. Leighton, and M. A. Vetter leading to this species. The answers are in the order you would normally work through the key. 

	Spikelets usually 2 or more, drooping or spreading on peduncles; leaf-like inflorescence bracts present; distal-most cauline leaves with blades at least 1 cm long and usually longer than their sheaths (shorter in E. gracile); lower scales of spikelets usually fertile (subtending flowers).  NOT [Spikelets solitary, erect at tip of culm; leaf-like inflorescence bracts absent; distal-most cauline leaves usually reduced to bladeless sheaths; lower scales of spikelets usually empty (without flowers).]
	Leaf-like inflorescence bracts 1 - 5; leaf blades 1.5 - 6 (8) mm wide, flat proximally, trigonous at tip; scales 4 - 10 mm long, with apices acute.  NOT [Leaf-like inflorescence bracts 1; leaf blades 1 - 2 mm wide (to 3 mm in E. tenellum), channelled their full length and trigonous at tip; scales 3 - 4 mm long (to 4.5 mm in E. tenellum) with apices obtuse to subacute.]
	Midribs of scales fading distally and not reaching tip of scales; anthers 2 - 5 mm long; peduncles smooth or scabrous on angles only.  NOT [Midribs of scales prominent, enlarged distally and reaching tip of scales, sometimes excurrent; anthers 0.8 - 2 mm long; peduncles scabrous.]

Eriophorum: Answers to key questions in Rushes, Bulrushes & Pondweeds plus the remaining Monocots of Saskatchewan by V. L. Harms, A. L. Leighton, and M. A. Vetter leading to this genus. The answers are in the order you would normally work through the key. 

	Flowers and achenes naked in the axils of scales, not enclosed in a sac; flowers usually perfect (sometimes some flowers imperfect in Cyperus, Rhynchospora and Cladium).   NOT [. Flowers and achenes enclosed in a sac (perigynium) borne in the axils of scales; flowers imperfect.]
	Perianth bristles usually more than 10 per flower, much longer than the achenes, conspicuously elongated to over 10 mm long in fruit stage and usually obscuring most scales in spikelets.  NOT [Perianth bristles absent or up to 6 per flower; if more than 6, then only somewhat longer than the achenes.]

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

	plants not aquatic, or if growing in water, most of the plant emersed; NOT [plants aquatic, floating or submerged, with floating leaves or emersed inflorescence]
	culms usually solid; NOT culms usually hollow]
	leaves three-ranked; NOT [leaves two-ranked]
	inflorescence NOT [a dense, single, cylindrical spike 8-15 cm long, 1-2.5 cm thick],  if a single spike, less than 1 cm thick
	flowers not in globular heads; NOT [flowers in globular heads, the upper ones staminate, the lower ones pistillate]
	flowers solitary in the axil of a single bract (scale); NOT [flowers enclosed in two-ranked bracts with the lowest (glumes) empty]
	perianth absent or inconspicuous, not in two whorls; NOT [perianth present, conspicuous, in two whorls of 3 segments each, often brightly colored]
	perianth reduced to bristles or scales or lacking; NOT [perianth reduced to minute lodicules or lacking]