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]

Group2: 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 1 fertile floret; sterile florets if present, attached above or below the fertile floret; NOT [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)]

Muhlenbergia: Answers to key questions leading to this genus. 

	Spikelets pedicellate; inflorescence not as below; NOT [Spikelets sessile and closely oppressed to slender, 3-sided branches; inflorescence usually comprising over 1/2 of the plant height]
	Sterile florets, when present, attached to the rachilla distal to the fertile floret; NOT [Sterile florets 2, attached at base of the fertile floret, either rudimentary and lacking sexual parts, or large and staminate]
	Panicles contracted to open; if spike-like, then disarticulation above the glumes; calluses glabrous or bearded;  NOT [Panicles spike-like, dense, uninterrupted; disarticulation below the glumes (occasionally above the glumes early in the season for Phleum species) with spikelets at the top of the rachis falling and revealing the naked rachis in mature plants; calluses glabrous]
	Calluses glabrous or bearded with sparse hairs < 1 mm long; if callus hairs longer than 1 mm, then lemmas pubescent proximally with hairs similar in length to the callus hairs, and lemma awns, if present, attached at or just below the apex; NOT [Calluses densely to sparsely bearded with hairs 1-4.5 mm long; lemmas glabrous or rarely scabridulous-puberulent; lemma awns absent or attached to the lemma back usually below midlength]
	Spikelets not dorsally compressed, glumes usually 1-nerved; lemma not as below; NOT [Spikelets dorsally compressed; glumes 3-nerved; lemmas unawned, thicker and harder than glumes, indurate, the involute margins partially enclosing the indurate palea and forming a shiny, seed-like unit at maturity]
	Paleas ? the same length as lemmas; if paleas hyaline and as short as 3/4 lemma length, then lemmas awned from just below tip or paleas distinctly appearing 1-nerved; NOT [Paleas absent, minute or at most 3/4 the length of lemmas, thin, hyaline; lemmas thin-textured, membranous to hyaline, unawned or awned from the back]
	Plants perennial with open, contracted or spike-like panicles, or annual with panicles included in inflated sheaths; lemmas unawned or awned, if awns subterminal, then short (to 2.5 mm) and glumes subequal; NOT [Plants annual with contracted panicles; lemmas with subterminal awns (4) 8-10 (15) mm long; glumes unequal]
	Leaf blades <= 6 mm wide; ligules, if membranous then <= 3 mm long and not brownish; glumes sometimes scabridulous-scabrous distally; paleas 2-nerved; panicle spike-like, contracted or open, if open then not as below; NOT [Leaf blades 4-12 (20) mm wide; ligules membranous, 2-7 (10) mm long, brownish; glume keels scabrous to ciliate with short stiff hairs; paleas 1-nerved or appearing 1-nerved; panicles open, usually 20-30 cm long, lax, often nodding]
	Glumes equal to subequal; ligules membranous, to 3 mm long; lemmas usually mucronate or awned; if not, then panicle diffuse with a single minute spikelet at the tip of each hair-like branch; paleas similar size or narrower than the lemmas; leaf sheaths hyaline at summit; fruit a narrow, elongate caryopsis; NOT [Glumes subequal to unequal; ligules consisting of hairs <= 1 mm long; lemmas acute, not mucronate or awned; paleas as wide or wider than the lemmas, in some species enveloping the flower and splitting ventrally to release the ripe fruit; leaf sheaths often with tufts of hair at summit; fruit an ellipsoidal to globose utricle or achene]

Glomerata: Answers to key questions leading to this species

	Panicles contracted or spike-like at maturity, 0.1-3 cm wide with appressed to ascending branches; spikelets (1.5) 1.7-8 mm long on pedicels usually shorter than the spikelets or not much longer; NOT [Panicles diffuse at maturity, 4-16 cm wide with spreading branches; spikelets 1-2 mm long on long, slender pedicels]
	If present, callus hairs and hairs at base of the lemma <= 1.2 mm long and shorter than the lemma; NOT [Callus hairs and hairs at base of the lemma 2-3.5 mm long and as long as the lemma]
	Glumes (including awn) slightly shorter or distinctly longer than the lemma; lemmas pubescent proximally with hairs to 1.2 mm long; rhizomes present, creeping, 1-2 mm wide, scaly; NOT [Glumes at most 3/4 as long as the lemma; lemmas glabrous or short pubescent proximally with hairs < 0.7 mm long; rhizomes, if present, then slender and lacking scales]
	Glumes (including awns) 3-8 mm long, distinctly longer than the lemma; lemma hairs up to 1.2 mm long; NOT [Glumes (including awns) 1.5-3.7 mm long, <= the lemma; lemma hairs up to 0.7 mm long]
	Culms unbranched or branched from near base, terete; internodes puberulent to minutely roughened (rough to the touch) from summit to base or part way down from summit; leaf sheaths with visible midvein but not keeled; lemmas fairly densely pilose, ? uniformly green or plumbeous; ligule 0.2-0.6 mm long; anthers 0.8-1.5 mm long; caryopses to 1.6 mm long, oblong-cylindrical; NOT [Culms unbranched or branched from middle nodes, elliptic in cross-section; internodes smooth (smooth to the touch) except near summit where they may be puberulent; leaf sheaths somewhat keeled with a prominent midvein; lemma relatively sparsely pilose, often pale with dark green or plumbeous blotches; ligule 0.6-1.5 (1.7) mm long; anthers 0.4-0.8 mm long; caryopses to 2.3 mm long, linear-cylindrical]