Pungens: 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. 

Culms 3-angled (trigonous); inflorescences unbranched, usually a solitary spikelet cluster, sometimes a solitary spikelet; distal leaf blades 2 - 5 times as long as their sheaths and 2 - 9 mm wide; scale apices bifid with a notch 0.5 - 1 mm deep.  NOT [Culms round (terete) or nearly so; inflorescences usually branched, rarely a solitary spikelet (in S. subterminalis); distal leaf blades usually much shorter than their sheaths; if longer than their sheaths, then at most 1 mm wide; scale apices entire or shallowly notched to <= 0.5 mm deep.]

Schoenoplectus: 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 absent or up to 6 per flower; if more than 6, then only somewhat longer than the achenes.  NOT [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.]
	Inflorescence not a solitary, terminal spike; if solitary, terminal and spike-like, then inflorescence +/- terete.  NOT [Inflorescence a compressed, solitary, terminal spike bearing few-flowered spikelets attached in 2 rows.]
	Inflorescence usually with > 1 spikelet; if only 1 spikelet present, then inflorescence bract usually 10 - 200 mm long (but as short as 7 mm in Schoenoplectus subterminalis) and achenes 2 - 3.5 mm long.  NOT [Inflorescence a solitary terminal spikelet; inflorescence bracts absent or up to 8 mm long and only slightly longer than the spikelet; achenes usually <= 2 mm long (up to 2.3 mm in Eleocharis quinqueflora).]
	Achenes lacking a tubercle but sometimes beaked.  NOT [Achenes with a narrowly triangular tubercle.]
	Scales of spikelets spirally arranged; spikelets terete.  NOT [Scales of spikelets 2-ranked; spikelets flattened or 4-sided.]
	Plants without the following combination of characteristics.  NOT [Culms tall and slender, 30 - 100 cm high and 1 - 2 mm wide; inflorescences with stiffly ascending primary and secondary branches supporting 100 - 1,000 spikelets in compact clusters; achenes terete with bases discoid, truncate, impressed and flared.]
	Inflorescences not subtended by leaf-like bracts, the proximal bract terete, trigonous or thickly C-shaped in cross-section and resembling a continuation of the culm (making the inflorescence appear to be attached to the side of the culm although the bract may be pushed aside in Amphiscirpus as the spikelets mature); longest bracts exceeding the inflorescence or not; usually all leaves basal with blades often much shorter than their sheaths.  NOT [Inflorescences subtended by 2 or more leaf-like, erect to spreading bracts; longest bracts exceeding the inflorescence; leaves basal and cauline, or all cauline with cauline leaf blades well developed.]
	Achenes beaked; scales shiny or dull, various shades of brown without strongly contrasting midribs; ligules membranous, lacking hairs; culms and leaves +/- spongy due to presence of air cavities; proximal sheaths not disintegrating into fibers.  NOT [Achenes beakless; scales often glossy (as if lacquered), chestnut-brown with contrasting pale midribs; ligules ciliate usually with some hairs visible along the sheath summit where it joins the blade; culms and leaves wiry and tough, air cavities lacking; proximal sheaths often disintegrating into fibers.]

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]