Nodosus: 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. 

	Tepals not subtended by a pair of bracteoles; flowers borne in tight clusters of 2 -100 (sometimes 1-flowered in Juncus stygius var. americanus), these clusters (glomerules) subtended by small bracts; leaf  blades septate (in most species) or not.  NOT [Tepals subtended by a pair of floral bracteoles immediately below the flower; flowers borne singly in the inflorescence either +/- evenly distributed or +/- grouped in loose clusters (not in tight clusters, and if grouped in clusters individual flowers and paired floral bracteoles are still visible and not so tightly crowded such that individual flowers cannot be fairly easily identified); leaf blades, if present, not septate.]
	Leaf blades terete or +/-canaliculate or +/- flattened dorsiventrally (not flattened laterally or equitant), usually < 3 mm wide.  NOT [Leaf blades flattened laterally (folded lengthwise), ensiform and equitant, 1.5 - 6 mm wide.]
	Primary bracts not distinctly white-scarious, may be somewhat but not broadly inflated at base, apices obtuse to acute; tepals with margins narrower, to one-third width of tepals, indistinct or membranous or scarious; anthers much shorter to 2 times longer than filaments; styles of various lengths; capsules variously locular with mucros to 0.5 mm (0.5 - 0.7 mm in J. castaneus) or gradually tapering into long narrow beaks; leaf blades terete or subterete (laterally flattened to subterete in J. nevadensis) or canaliculate (J. castaneus, which is recorded only from the ne corner of the province), septate or indistinctly septate.  NOT [Primary bracts distinctly white-scarious and conspicuously inflated at the base, apices narrowly attenuate to caudate; tepals with wide (>= one-third width of tepals) scarious margins; anthers 2 - 3 times longer than filaments; styles 0.6 - 0.9 (1.2) mm long; capsules 3-locular with (0.5) 0.6 - 1.0 (1.1) mm long mucros; leaf blades +/- canaliculate, not septate.]
	Plants without the following combination of characteristics (but note that the glomerules may be solitary or few).  NOT [Glomerules solitary (rarely 2), (1) 3 - 4 (5)-flowered; primary bracts about equal to inflorescences in length; leaves all basal, blades 0.3 - 1 mm wide, 20-80 (100) mm long, with apices blunt, black and callose; anthers ca. one-quarter filament length; plants 3-25 (35) cm high, recorded from only 2 locations in northern boreal and subarctic transitional forest regions.]
	Capsules shorter, up to 5 mm long (except up to 5.7 mm long in Juncus torreyi), included or exserted; seeds 0.4 - 1.2 mm long with very short apicula; leaf blades mostly distinctly septate (septa externally indistinct in Juncus mertensianus).  Subg. Septati.  NOT [Capsules (5) 5.5 - 8.5 (9) mm long, long-exserted; seeds 2.4 - 3.5 mm long including conspicuous 0.8 - 1.1 (1.6) mm long apicula; leaf blades indistinctly septate; not found south of the boreal forest.]
	Inflorescences, if compact glomerules, then glomerules 2 - 15+ (very rarely 1); glomerules 2 - 100 flowered, variously-shaped; tepals green, stramineous, chestnut- to dark brown but not dark purplish brown to black; capsules 1-locular or pseudo-3-locular or imperfectly-3-locular; leaf blades terete (flattened to subterete in Juncus nevadensis), septate.  NOT [Inflorescences solitary (very rarely a tightly-congested cluster of 2) terminal glomerules; glomerules 12 - 60 flowered, globose to subglobose; tepals dark purplish brown to black; capsules 1-locular; leaf blades septate but septa externally indistinct.]
	Primary bracts usually longer to much longer than the inflorescence; capsules tapered from near base into long narrow beaks; tepals lanceolate-subulate, acuminate; glomerules 6 - 15 mm long with 6 - 100 flowers; capsules 1-locular. NOT [Primary bracts <= the inflorescences; capsules rounded, obtuse or acute with mucros or short beaks; tepals narrowly lanceolate to oblong with tips acute-acuminate, sometimes mucronate, rarely obtuse; glomerules (2) 3 - 10 mm long with 2 - 13 flowers; capsules 1-locular or imperfectly-3-locular.]
	Glomerules 6 - 10 mm long, 6 - 10 (12) mm wide, with 6 - 30 flowers; tepals 2.4 - 4.2 mm long, much shorter than capsules; stamens 3 or 6; rhizomes swollen at nodes but lacking tubers; plants smaller with culms 4 - 55 (60) cm high and 1 - 3 mm wide.  NOT [Glomerules 10 - 15 mm long, 10 - 15 mm wide, with 25 - 100 flowers; tepals (3) 3.4 - 6 mm long, shorter than or +/- equal to capsules; stamens 6; rhizomes with small tubers at nodes; plants taller with culms (20) 30 - 100 cm high and 3 - 5 (6) mm wide.]

Juncus: 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. 

Leaves various, glabrous; sheaths open, often with margins projected as auricles; flowers with or without a pair of floral bracteoles immediately below the tepals; capsules 1- or 3-locular (or pseudo- or incompletely-3-locular), placentation axile or parietal; seeds many.  NOT [Leaves +/- flat and grass-like, sparsely to densely ciliate; sheaths closed (or sometimes partially splitting later), auricles absent; flowers with 1 - 2 floral bracteoles immediately below the tepals; capsules 1-locular, placentation basal; seeds 3.]

Juncaceae: 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]
	flowers not in globular heads; NOT [flowers in globular heads, the upper ones staminate, the lower ones pistillate]
	flowers in branched inflorescences; NOT [inflorescence a dense, single, cylindrical spike 8-15 cm long, 1-2.5 cm thick], NOT [flowers in spike-like racemes]
	perianth in two whorls, each of three segments
	perianth segments inconspicuous and scale-like; NOT [perianth segments conspicuous and often brightly colored], NOT [perianth of greenish sepals and petals]