Multitribe: Answers to key questions leading to this tribe. 

	Mature inflorescence, if breaking into units, then the units not as below; NOT [Mature inflorescence breaking into spikelet units consisting of a sessile fertile spikelet, a hairy pedicel with or without a sterile spikelet at tip, and a hairy rachis joint, all arising at the same point (a node) in specialized panicle branches called rames]
	Spikelets not as below; sterile florets if present, either located distal to the fertile floret(s) on the rachilla or paired and attached at the base of a single fertile floret, not paired with the upper glume as below; lemma and palea variously textured, enclosing the flower or not; disarticulation usually above the glumes; NOT [Spikelets usually dorsally compressed, appearing 1-flowered but containing 1 fertile floret and 1 sterile floret, the latter attached to the base of fertile floret opposite the upper glume, resembling the upper glume, and together with the upper glume enveloping the fertile floret; lower glumes minute (sometimes absent) to 3/4 as long as upper glumes and typically wrapping most of the way around the pedicel at base; fertile floret seed-like with chartaceous-indurate lemma and palea enclosing flower and fruit; disarticulation below the glumes with rare exceptions]
	Spikelets 1 to many-flowered, subtended by a pair of glumes (only 1 on lateral spikelets in Lolium); palea margins enclosed or not; plants of dry or wet habitats; NOT [Spikelets 1-flowered, lacking glumes; margins of the palea tightly enclosed by the lemma margins on female or perfect florets; plants of wetlands, often emergent aquatic]
	Inflorescence not as below; if a terminal spike, then the lateral spikelets attached edgewise to the rachis with inner (upper) glume wanting (as in Lolium); NOT [Inflorescence a terminal spike with sessile or subsessile spikelets attached broadside at nodes on opposite sides of the rachis]
	Lemmas and lemma awns not as below; if lemma indurate and enveloping the floret, then glumes distinctly dorsally compressed and calluses glabrous (as in Milium); NOT [Lemmas stiff to indurate, firmer than the glumes, surrounding the palea and often overlapping along the margins, closed at the tip as well as at the base, often pubescent; lemma awns (caducous or wanting in some species) terete and encircled at the base by the closed tip of the lemma; calluses usually pubescent, rarely glabrous]

Group3: Answers to key questions leading to this group. 

	If plants mat-forming, then inflorescences not as below; NOT [Mat-forming annuals or perennials either with clusters of spikelets hidden by sharp-pointed leaves at branch tips, or with pistillate inflorescences consisting of burs partially hidden within expanded leaf sheaths with only the staminate inflorescences exceeding the upper leaves]
	Inflorescence not as below, the spikelets usually on pedicels in panicles that range from spike-like to open; if spikelets sessile, then they either have more than 1 fertile floret per spikelet or are not arranged like the teeth of a comb; NOT [Inflorescence consisting of spike-like panicle branches with sessile- subsessile, closely imbricate, regularly-spaced, parallel spikelets all directed toward 1 side of the branch like the teeth of a comb (loosely so in Bouteloua curtipendula); fertile florets 1 per spikelet]
	Spikelets with more than 1 fertile floret; sterile florets if present, attached above the fertile florets (Phragmites, with sterile florets attached above and below fertile florets, is an exception); NOT [Spikelets with 1 fertile floret; sterile florets if present, attached above or below the fertile floret]

Glyceria: Answers to key questions leading to this genus. 

	Inflorescence a panicle with all spikelets subtended by 2 glumes; NOT [Inflorescence a terminal spike; lateral spikelets positioned edgewise to the rachis and lacking a glume on inside edge]
	Spikelets usually pedicellate; if sessile-subsessile, then not arranged as below; NOT [Spikelets sessile or subsessile on spike-like panicle branches, or on short secondary branches in dense one-sided clusters at branch tips]
	Rachillas glabrous or pubescent; if pubescent, then hairs much shorter than the lemmas; panicles and plants not as below; NOT [Rachillas with silky hairs (4) 6-10 mm long, as long as the lemmas or nearly so; panicles 15-35 (45) cm long, 8-20 cm wide at maturity, dense, feathery; plants 10-30 (40) dm tall, with stout, creeping rhizomes and often forming dense stands]
	Glumes < 17 mm long; if glumes longer, then plants perennial; NOT [Glumes 18-32 mm long, usually exceeding the lemmas; plants annual]
	Plants without the below combination of characteristics; NOT [Culm sheaths closed to near summit; leaf blades flat; spikelets 12-40 (55) mm long; lemmas 7-14 (21) mm long, usually awned, the awns terminal or subterminal; calluses glabrous; ovaries and caryopses with pubescent apical appendage; caryopses adnate to paleas at maturity]
	Plants without the below combination of characteristics; NOT [Rachilla conspicuously pubescent with straight hairs; calluses bearded; spikelet 2 (3-4) flowered; lemma 2-4 toothed, sometimes obscurely so, sometimes entire; lemma awns attached dorsally or just below apex, often exceeding the lemma apex by only 1-2 mm (awn may be absent in Trisetum wolfii)]
	Lemmas unawned or awned; if awns present, then the awns straight and terminal or subterminal, and the calluses glabrous or with short, sparse hairs; NOT [Lemmas awned, the awns 3-17 mm long, slightly outcurving or geniculate, attached dorsally about midlength, or at base of 0.5-8 mm long apical teeth; calluses with dense or long hairs]
	Lemmas with 5 - 11 visibly-raised nerves or nerves too obscure to count; NOT [Lemmas with 3 visibly-raised nerves (1 midnerve and 2 lateral nerves)]
	Lemmas rounded or weakly keeled on the back, with 5-11 visibly-raised nerves that are +/- parallel their full length, their tips not converging distally; calluses glabrous; NOT [Lemmas not as above, either keeled, or with obscure nerves or nerves converging distally; calluses glabrous or pubescent]
	Leaf sheaths closed for l/2 to 3/4 of their length, or to near top; NOT [Leaf sheaths open to base]
	Lemmas 1.2-5.4 mm long, 5-7-nerved; lower glumes 0.5-2.8 mm long, 1-nerved; culms not swollen into a corm at base; NOT [Lemmas 6-12 mm long, 7-11 nerved; lower glumes 5.5-10.5 mm long, 3-5 nerved; culm base swollen into a corm]

Borealis: Answers to key questions leading to this species

Spikelets linear (with sides parallel to each other), usually >= 8 mm long, 8-12-flowered; rachilla internode length 0.6-3.5 mm; upper glumes (2) 2.8-3.5 mm long; panicle to 2 (5) cm wide, usually contracted, the primary branches appressed to ascending and each bearing up to 6 spikelets; ligules 4-12 mm long, often tearing into long trailing fragments; anthers 3; NOT [Spikelets ovate to elliptic (widening near base or middle) or oblong, rarely linear, 1.8-8 mm long, 3-10-flowered; rachilla internode length 0.1-0.8 mm; upper glumes 0.6-2.7 (2.8) mm long; panicle 2.5-21 cm wide, open, pyramidal, the primary branches ascending to divergent, often drooping at maturity, bearing 15-80+ spikelets; ligules to 6 (7) mm long, variously tipped but not as above; anthers 2 or 3]