1	"Leaf blade base constricted above sheath, forming false petiole; stem woody"	"Phyllostachys {Phyllostachys aurea}"
1	"Leaf blade base not constricted, not forming false petiole, forming open or closed tubular sheath; stem generally herbaceous"	2
2	"Spikelets enclosed in bristly to spiny, bur-like involucre"	Cenchrus
2	"Spikelets not enclosed in bristly to spiny, bur-like involucre"	3
3	"Some or all florets modified into bulblets with conspicuous, awn-like tails"	"Poa bulbosa subsp. vivipara"
3	"Florets not modified into bulblets"	4
4	"Leaf blades, at least upper, generally stiff at maturity, sharp-pointed and conspicuously arranged in 2 vertical rows"	5
4	"Leaf blades generally soft, rounded to acute, but not sharp-pointed (except <i>Blepharidachne</i>, <i>Munroa</i>), not conspicuously arranged in 2 vertical rows (except <i>Muhlenbergia asperifolia</i>)"	6
5	"Spikelets unisexual, plants generally dioecious; plants of salt marshes and moist alkaline sites"	Distichlis
5	"Spikelets bisexual; plants known only from sand dunes in Inyo Co."	"Swallenia {Swallenia alexandrae}"
6	"Leaf blade and sheath undifferentiated; stem internodes solid; ligules 0"	7
6	"Leaf blade and sheath clearly differentiated; stem internodes generally hollow; ligules generally present"	9
7	"Spikelets 2-ranked on inflorescence axis"	Orcuttia
7	"Spikelets spirally inserted on inflorescence axis"	8
8	"Plant glandular-sticky at maturity; inflorescence a dense, cylindric spike, generally fully exserted at maturity; spikelets dorsally compressed"	"Neostapfia {Neostapfia colusana}"
8	"Plant not glandular-sticky at maturity; inflorescence club-shaped, often +- enclosed by leaves at maturity; spikelets laterally compressed"	Tuctoria
9	"Basal or subterranean internodes swollen, bulb- or corm-like"	10
9	"Basal or subterranean internodes not swollen, not bulb- or corm-like"	12
10	"Inflorescence spike-like, cylindric or ovoid, branches not evident; glumes winged"	"Phalaris aquatica"
10	"Inflorescence panicle-like, open with evident branches; glumes not winged"	11
11	"Sheath open; glumes +- enclosing florets; lower lemma awns bent, twisted"	"Arrhenatherum {Arrhenatherum elatius}"
11	"Sheath closed to near tip; glumes = lowest floret; lower lemma awns generally 0 or awns straight, untwisted"	Melica
12	"Robust perennial herb, generally 1.5--7 m; stem 0.5--3 cm diam, tough, hardened to woody, generally persisting; inflorescence terminal, often conspicuously plume- or fan-like"	"Poaceae Group 1"
12	"Low annual to mid-sized perennial herb, generally < 1.5 m; stem generally < 5 mm wide, strictly herbaceous, generally dying back annually; inflorescence axillary, terminal, or both, but not conspicuously plume- nor fan-like"	13
13	"Plants generally < 15 cm; mature inflorescence not clearly exceeding leaves, often +- enclosed in upper sheath"	14
13	"Plants generally >> 15 cm; mature inflorescence clearly exceeding upper leaves"	19
14	"Floret 1; lemma 1-veined"	Crypsis
14	"Florets 2+; lemma >= 3-veined"	15
15	"Lemma awn 0"	16
15	"Lemma awns 1 or 3"	17
16	"Inflorescence subtended by 5--10 bristles; spikelets 1--2 mm; florets 2"	"Pennisetum clandestinum"
16	"Inflorescence not subtended by bristles; spikelets 6--10 mm; florets 3--5"	"Sclerochloa {Sclerochloa dura}"
17	"Lemma 3-lobed, conspicuously ciliate; upper florets 3-awned"	"Blepharidachne {Blepharidachne kingii}"
17	"Lemma 2-lobed or tapering to awn"	18
18	"Glumes 6--9 mm, > lemma; lemma 2-lobed"	"Dasyochloa {Dasyochloa pulchella}"
18	"Glumes 2--4 mm, < lemma; lemma tapering to point"	"Munroa {Munroa squarrosa}"
19	"Spikelets 1--2 per inflorescence"	20
19	"Spikelets few to many in a well-developed inflorescence"	21
20	"Glumes < lowest floret; awns (if present) not twisted, nor bent"	"Brachypodium distachyon"
20	"Glumes > lowest floret; awns twisted and bent"	"Danthonia unispicata"
21	"Spikelets subtended by 1+ bristles, sterile branches, or long, silky hairs > spikelet"	22
21	"Spikelets not subtended by bristles or by long, silky hairs"	26
22	"Spikelets subtended by long, silky hairs from their bases, rachis joints, or pedicels"	23
22	"Spikelets subtended by 1 or more generally stiff bristles or sterile branches"	24
23	"Spikelets dissimilar, sessile bisexual, stalked sterile"	Bothriochloa
23	"Spikelets similar, bisexual"	"Imperata {Imperata brevifolia}"
24	"Bristles short-stiff-hairy"	Setaria
24	"Bristles scabrous to long-ciliate"	25
25	"Inflorescence panicle-like, branches 2--7"	Andropogon
25	"Inflorescence spike-like, dense, cylindrical"	Pennisetum
26	"Glume and/or lemma bodies covered with long, silky hairs"	27
26	"Glumes and lemma bodies glabrous to short-hairy"	29
27	"Inflorescence dense, ovoid or oblong, head-like; spikelets 1-flowered"	"Lagurus {Lagurus ovatus}"
27	"Inflorescence open, branching evident; spikelets 2-flowered"	28
28	"Spikelets paired on one side of a slender rachis"	"Digitaria californica"
28	"Spikelets single on ends of short capillary branches"	"Melinis {Melinis repens subsp. repens}"
29	"Glumes or lemma (perhaps only in a unisexual spikelet) with 3--9 awns or awn-like segments (lateral awns sometimes << than central 1)"	30
29	"Glume or lemma awns 0--2"	36
30	"Lemma awns 9, plumose"	"Enneapogon {Enneapogon desvauxii}"
30	"Lemma awns 0--3, not plumose"	31
31	"Lower glume with (2)3--9 awns or awn-like segments"	32
31	"Lower glume awn 0 or 1"	34
32	"Spikelets 1--flowered"	"Muhlenbergia alopecuroides"
32	"Spikelets 2--5 flowered"	33
33	"Annual; spikelets 1 per node"	Aegilops
33	"Perennial herb; spikelets 2(3--4) per node"	"Elymus multisetus"
34	"Spikelets 1-flowered"	Aristida
34	"Spikelets 2--several-flowered"	35
35	"Inflorescence open, panicle-like; spikelets pistillate"	"Scleropogon {Scleropogon brevifolius}"
35	"Inflorescence 1--many raceme-like or spike-like 1&deg; branches; spikelets bisexual"	Bouteloua
36	"Spikelets generally dorsally compressed (cylindrical); florets 2, lower sterile or staminate, often reduced to sterile lemma, upper floret bisexual; glume and fertile lemma texture noticeably dissimilar; spikelets breaking apart below the glumes, falling singly or in pairs with segments of inflorescence axis attached"	"Poaceae Group 2"
36	"Spikelets generally laterally compressed or cylindric; florets 1--many, if > 1, lower one(s) generally fertile, upper reduced and sterile; glume and fertile lemma texture generally similar; spikelets generally breaking apart above glumes and between florets or floret clusters"	37
37	"Plants bearing markedly dissimilar spikelets in the same or separate inflorescences"	38
37	"Plants bearing similar spikelets, differing only in size and degree of maturity"	44
38	"Spikelets unisexual"	39
38	"Spikelets bisexual or sterile"	40
39	"Terrestrial perennial herb to 20 cm; creosote scrubland"	"Scleropogon {Scleropogon brevifolius}"
39	"Aquatic annual 1--1.5 m; cultivated fields and adjacent ditches"	"Zizania {Zizania palustris var. interior}"
40	"Inflorescence spike-like"	41
40	"Inflorescence panicle-like, open to dense"	42
41	"Stem internodes solid; spikelets sessile"	Hilaria
41	"Stem internodes hollow; central spikelet sessile, laterals stalked (except in <i>Hordeum vulgare</i>)"	Hordeum
42	"Lemma awn 0; spikelets in groups of 7 (1 fertile + 6 sterile)"	"Phalaris paradoxa"
42	"Lemma awned; spikelets paired or in pendant clusters"	43
43	"Inflorescence panicle-like with drooping clusters of 1 fertile spikelet and 1--3 sterile ones; spikelet clusters falling as 1 unit"	"Lamarckia {Lamarckia aurea}"
43	"Inflorescence head-like or cylindric, spikelets generally paired; spikelets falling separately"	Cynosurus
44	"Spikelets sessile or stalked on an unbranched central axis"	"Poaceae Group 3"
44	"Spikelets attached to 1&deg; or 2&deg; branches (dissection may be needed to reveal branches)"	45
45	"Inflorescence a series of 2 or more digitate, raceme-like, clusters, or whorls of 1&deg; branches"	"Poaceae Group 4"
45	"Inflorescence much-branched, 2&deg; or 3&deg; branching evident"	46
46	"Spikelets 1-flowered"	"Poaceae Group 5"
46	"Spikelets 2--many-flowered (sterile florets reduced to small scales or hairy, awl-like rudiments)"	47
47	"Spikelets 2--8 per node"	Elymus
47	"Spikelets 1 per node"	48
48	"Spikelets unisexual; plants dioecious"	49
48	"Spikelets bisexual"	51
49	"Leaf tips prow-shaped; lemma base with cottony or cobwebby tuft of hairs"	Poa
49	"Leaf tips flat; lemma bases glabrous to scabrous"	50
50	"Plants rhizomatous; lemma glabrous, veins 9--11, inconspicuous"	Distichlis
50	"Plants densely tufted; lemma scabrous, veins (3)5(7)"	"Festuca kingii"
51	"Fertile florets 2+ (occasionally 1 in <i>Dissanthelium</i>)"	52
51	"Fertile floret 1"	56
52	"Lemma veins generally (3)5--several, sometimes very faint"	"Poaceae Group 6"
52	"Lemma veins 3, generally prominent (laterals sometimes near margins)"	53
53	"Glumes > florets; florets 2(3) --- ChI only"	"Dissanthelium {Dissanthelium californicum}"
53	"Glumes < upper florets; florets 3--many"	54
54	"Lemma veins glabrous"	Eragrostis
54	"Lemma veins hairy, at least below"	55
55	"Leaf blade margin white; lemma awn 0.5--2.5 mm; stigmas white"	"Erioneuron {Erioneuron pilosum}"
55	"Leaf blade margin green; lemma awn 0; stigmas purple"	"Tridens {Tridens muticus var. muticus}"
56	"Spikelet breaking below glumes; lower floret bisexual, awn 0; upper floret staminate, awned"	Holcus
56	"Spikelet breaking above glumes; staminate or sterile floret(s) below fertile one (sometimes << fertile and easily overlooked)"	57
57	"Fertile floret generally awned"	58
57	"Fertile floret awn 0"	59
58	"Perennial herb; nodes green or straw-colored; spikelets breaking apart below lowest floret"	"Arrhenatherum {Arrhenatherum elatius}"
58	"Annual; nodes purple-black; spikelets breaking apart above lowest floret"	"Ventenata {Ventenata dubia}"
59	"Lower florets reduced to sterile lemma < 1/2 fertile floret"	Phalaris
59	"Lower staminate or sterile florets >= fertile one"	60
60	"Spikelets straw-colored or brown at maturity; stamens 2--3; auricles 0 (except in <i>Anthoxanthum aristatum</i>, <i>A. odoratum</i>)"	Anthoxanthum
60	"Spikelets green or purplish at maturity; stamens 3 or 6; auricles ciliate"	Ehrharta