Carex trisperma
 
Three-Seeded Sedge

Terminal Spike, Perigynia Spread Out

4.1 km North of Intersection of Highways 980 and 981,
East Side of Road
31-May-2016

The perigynia were manually spread out in this specimen.

I am not sure of my identification of this specimen.  The number of spikes in the inflorescence is larger than is typical for this species.  In addition, the arrangement of the flowers in the spikes is not clearly gynecandrous.  However, I concluded it was the closest match to any of the sedges known to occur in Saskatchewan.

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Trisperma: 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. 
bulletStigmas 2; achenes lenticular.  NOT [Stigmas 3; achenes three-sided, occasionally terete, though their shape may be concealed by flattened perigynia.]
bulletSpikes 2 or more per culm, terminal and lateral; spike bracts present on lateral spikes; lowest spike bracts usually evident, often conspicuous, even in compact heads composed of densely bunched and indistinguishable spikes (except in C. maritima, C. chordorrhiza and C. microptera).  NOT [Spikes 1 per culm, terminal; spike bracts absent]
bulletIndividual spikes distinguishable in an open inflorescence, or indistinguishable in a compact head; spikes in any one inflorescence alike in appearance due to their similar composition (i.e. all are gynecandrous, androgynous, pistillate or staminate), sessile.  NOT [Individual spikes distinguishable in an open inflorescence (densely bunched in C. bicolor); spikes in any one inflorescence either markedly different in appearance (with terminal spike staminate and lateral spikes pistillate), or subtly different in appearance (with terminal spike gynecandrous and lateral spikes pistillate), sessile or stalked.]
bulletCulms loosely to densely cespitose (occasionally mat-forming rather than in discrete clumps); rhizomes, if present, usually short with culms arising close together along them.  NOT [Culms single, or a few together, well-spaced along conspicuous rhizomes or stolons.]
bulletSpikes gynecandrous, (terminal spikes may be staminate in SK material of C. mackenziei; pistillate or staminate spikes occur in Sect. Stellulatae, a group distinguished by spongy tissue filling lower one-third to one-half of the perigynium); if heads have indistinguishable spikes, the heads are usually +/- as wide as they are long and usually widest in middle or toward base.  NOT [Spikes androgynous, (lateral spikes occasionally pistillate in C. prairea); if heads have indistinguishable spikes, the heads are usually oblong to elongate in shape.]
bulletLower 3 or 4 spike bracts usually scale-like or bristle-like; if lowest is long and leaf-like, then it is shorter than half the culm length or it appears to be an extension of the culm to which inflorescence is attached laterally (as in C. athrostachya); perigynia various.  NOT [Lower 3 or 4 spike bracts long, pale-green and leaf-like; lowest bract 5-15 (20) cm long, usually half to fully as long as culm below inflorescence; perigynia 5 mm long or longer, narrowly lanceolate.]
bulletPerigynium distinctly wingless though margins may be thickened as rounded or raised nerves; mature achene filling width of perigynium body; perigynium base or wall thickened by spongy tissue or cells; beak present or absent. NOT [Perigynium margins flattened as a narrow or wide wing for all or part of perigynium length (wing reduced to raised thickened nerve along body in C. adusta); mature achene narrower than perigynium body; beak present (though may be ill-defined); neither perigynium base nor perigynium wall thickened with spongy tissue.]
bulletPerigynium wall thickened by spongy cells toward base (usually only visible after cutting perigynium in longitudinal section), surface puncticulate giving it a sparkly, beaded look under magnification.  NOT [Bottom one-third to one-half of perigynium filled with spongy tissue below achene; surface not punctate or puncticulate (conspicuously or minutely beset with tiny pits).]
bulletBeak measurable, 0.25-1.0 mm long; perigynia a brighter green with scales often tinged with shades of brown (often colorless in C. canescens); spike shape variable; perigynia 1-20 per spike.  NOT [Beak reduced to a nubbin too short to measure; perigynia muted green with scales translucent to whitish giving the inflorescence a pale, milky-green cast; spikes nearly round to short oblong; perigynia 3-10 (15 fna) per spike.]
bulletLowest 1 or 2 spikes remote, about as wide as long, few-flowered (fewer than 10 perigynia per spike); beak about 5 mm long.  NOT [Lowest 1 or 2 spikes usually separate to overlapping; if lowest spike remote then spikes longer than wide, perigynia (5) 10-20 (30) per spike, terminal spike often V-shaped with staminate flowers at base, beak ill-defined and about 0.25 mm long.]
bulletSpikes 2-4; lowest spike attached 1-4 cm below one above; upper spikes remote, separate or overlapping; perigynia 1-5 per spike, 2.5-3.7 mm long; lowest spike bract surpassing next spike or overtopping inflorescence and often wider than rachis adjacent to it; rachis often diverging where lowest bract arises making inflorescence appear forked at base of lowest spike.  NOT [Spikes 3-7 (10), only lowest spike remote, upper separate to overlapping; perigynia 5-10 per spike, 2.5 mm long at most; lowest spike bract varies in length from a bit longer than spike to several cm long, usually narrower than rachis adjacent to it; rachis seldom bent at a right angle where lowest bract arises.]