Capillaris: Answers to key questions in Sedges (Carex) of Saskatchewan, Fascicle 3, Flora of Saskatchewan by Anna Leighton leading to this species. The answers are in the order you would normally work through the key. 

	Stigmas 3; achenes three-sided, occasionally terete, though their shape may be concealed by flattened perigynia.  NOT [Stigmas 2; achenes lenticular.]
	Spikes 2 or more per culm, terminal and lateral; spike bracts present on lateral spikes (except in Section Phyllostachyae), lowest bract usually evident, often conspicuous.  NOT [Spikes 1 per culm, terminal; spike bracts absent.]
	Lower pistillate scales not bract-like or leaf-like but similar in size and shape to individual perigynia (up to twice as long as perigynia in C. magellanica ssp. irrigua).  NOT [Lower pistillate scales resembling green, leaf-like bracts much longer and wider than individual perigynia.]
	Perigynia glabrous (i.e. lacking pubescence). NOT [Perigynia sparsely to densely pubescent or puberulent (in C. pedunculata pubescence represented by very short hairs scattered near tip; in some species of Sect. Acrocystis, perigynia may be glabrous or virtually hairless, but all members of this group have convexly 3-sided to terete achenes with tight-fitting perigynia and a stipe-like base about equal to beak in length).]
	Beak absent or less than 0.5 mm long; if more than 0.5 mm long, then terminating in an orifice without teeth.  NOT [Beak over 0.5 mm long and usually visibly bidentate (teeth hyaline in C. sprengelii, inconspicuous in C. viridula, very short in C. oligosperma).]
	Leaves and sheaths glabrous; plants cespitose or rhizomatous.  NOT [Leaves and sheaths pubescent; plants cespitose]
	Lowest spike bract sheath at least (2.5) 3 mm long; NOT [Lowest spike bracts sheathless or with sheaths 1-2 mm long (to 3 or 4 mm long in Section Limosae)]
	Plants cespitose; terminal staminate spike at most 10 mm long, inconspicuous among, or overtopped by, distal pistillate spike(s).  NOT [Plants rhizomatous (some species forming colonies); staminate spike 12-25 mm long, conspicuous, positioned well above upper pistillate spike.]
	Spike bract blades as long as sheath or longer; leaves 1-10 mm wide.  NOT [Spike bract sheaths tipped with hyaline blades about half the length of sheath or shorter; leaves fine, hair-like, usually less than 0.5 mm]
	Pistillate spikes on filiform stalks, lowest usually drooping.  NOT [Pistillate spikes all erect on firm stalks, or stalkless]