Stipeae: 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 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; NOT [Lemmas and lemma awns not as above; if lemma indurate and enveloping the floret, then glumes distinctly dorsally compressed and calluses glabrous (as in Milium)]
	Lemma awns 1, persistent or caducous; lemmas usually pubescent; NOT [Lemma awns 3, persistent; lemma glabrous]

Achnatherum: Answers to key questions leading to this genus (in tribe Stipeae). 

	Lemma awns 1-32+ mm long; lemmas 1.5-7 mm long; callus to 2 mm long, blunt to pointed but not sharp-tipped; glumes 2.5-13 mm long; NOT [Lemma awns 50-225 mm long; lemmas 7-25 mm long; callus 2-6 mm long, sharp-tipped; glumes 15-45 mm long]
	Basal blades not overwintering, usually rolled and narrow, if flat, then to 5 mm wide and not twisted at base; cauline blades ± well-developed, flag leaf blade more than 1 cm long; other features variable; NOT [Basal blades green late in the season, overwintering, flat to ± revolute, 4-9 mm wide, tapering at both ends and twisted 180° at base; cauline blades reduced or obsolete, the flag leaf blade at most 1.2 cm long; glumes green with scarious margins and tip; panicle narrow with appressed branches; callus blunt, densely pubescent]
	Lemma apex not forming such a crown; sheaths not villose near throat but if short tufts of hair present, then collars glabrous; glumes, if hyaline, then with less conspicuous nerves; glume tips at most long-attenuate; NOT [Lemma apex forming a straight-sided, ± glabrous crown rimmed with hairs 0.5-0.75 mm long; sheaths villose near throat; collar pubescent on basal and lower cauline leaves; glumes hyaline with conspicuous, green nerves at base; glume tips filiform]
	Glumes 5.5-12.5 mm long; paleas <= lemmas; if paleas = lemmas, then lemmas densely, evenly pilose with hairs 2.5-6 mm long and glumes sac-shaped at base and abruptly narrowing to an acuminate tip; NOT [Glumes 2.5-6 mm long; paleas >= lemmas]

Hymenoides: Answers to key questions leading to this species (in genus Achnatherum)

Glumes papery, sac-shaped at base and abruptly narrowing to a long-pointed tip; lemmas densely and evenly pilose with hairs 2.5-6 mm long, the tips of the hairs visible between the glume tips; lemma awns 3-6 mm long, caducous, straight, not twisted at base; paleas glabrous and about equal to lemmas in length and width; panicles diffuse with divaricately forked branches, and spikelets solitary at tips of long, spreading pedicels; NOT [Glumes thinly membranous, hyaline distally, lanceolate, not sac-shaped at base; lemmas pubescent with hairs 2 mm long at most and not visible between the glume tips; lemma awns >= 15 mm long, persistent, weekly twice-geniculate, twisted below; paleas pubescent and at most 2/3 the lemma length and much narrower than the lemmas; panicles not as above.]