1	Spikelets 2 per node (at least at middle nodes), rarely 3 or 4 per node		(2)
+	Spikelets 1 per node		(15)
2 (1)	Glumes much shorter than lemma		(3)
+	Glumes slightly shorter than or equaling lemma		(8)
3 (2)	Lemma awn more than 10 mm		(4)
+	Lemma awn less than 7 mm		(6)
4 (3)	Leaf blade flat, 10–15 × 0.5–1 cm.		7 E. sibiricus
+	Leaf blade flat or ± rolled, 3–10 × 0.2–0.5 cm		(5)
5 (4)	Leaf blade flat, 3–5 mm wide; glume apex with awn 1–4 mm.		8 E. nutans
+	Leaf blade ± rolled, ca. 2 mm wide; glume apex mucronate or acuminate.		9 E. atratus
6 (3)	Leaf blade 1.5–3 mm wide; glumes oblong, 2–3 mm, 3-veined.		12 E. sinosubmuticus
+	Leaf blade 3–5 mm wide; glumes ovate-lanceolate, oblong-lanceolate, or narrowly lanceolate, 3–4 mm, 1–3-veined		(7)
7 (6)	Spikelets 13–15 mm, with 4–6 florets; glumes oblong-lanceolate or ovate-lanceolate.		10 E. breviaristatus
+	Spikelets 10–12 mm, with 3 or 4 florets; glumes narrowly lanceolate.		11 E. alpinus
8 (2)	Rachis densely hirsute, nodes swollen.		6 E. villifer
+	Rachis not densely hirsute, nodes not swollen		(9)
9 (8)	Culms, leaf blade, and spike all farinaceous; glumes and lemma ± purplish punctate; awn purple, pubescent.		5 E. purpuraristatus
+	Culms, leaf blade, and spike not farinaceous; glumes and lemma not purplish punctate; awn green, glabrous but scabrous		(10)
10 (9)	Glumes hirsutulous along veins		(11)
+	Glumes scabrous along veins		(12)
11 (10)	Leaf sheath glabrous; spike purplish; glume apex acuminate or with point ca. 1.5 mm.		2 E. barystachyus
+	Leaf sheath villous at base; spike green; glume apex usually with awn to 5 mm.		4 E. dahuricus
12 (10)	Glume apex acuminate or with awn 1–4 mm; lemma with usually erect awn (3–)5–13 mm		(13)
+	Glume apex with awn 5–7 mm; lemma with usually reflexed awn 8–20(–40) mm		(14)
13 (12)	Culms to 120 cm tall, 4- or 5-noded; leaf blade 10–20 × 0.6–1.4 cm; lemma glabrous, or hirsutulous in distal half.		1 E. tangutorum
+	Culms 40–80 cm tall, 2- or 3-noded; leaf blade 5–12 × ca. 0.5 cm; lemma puberulent throughout		4 E. dahuricus
14 (12)	Leaf blade 1–1.6 cm wide; spikelets 2 or 3(or 4) per node.		3 E. excelsus
+	Leaf blade 0.5–0.9(–1.2) cm wide; spikelets 2 per node, or 1 per node in proximal and distal parts of spike.		4 E. dahuricus
15 (1)	Lemma with long, strongly recurved awn at seed maturity; if lemma awn short or nearly absent, or only slightly curved, then palea shorter than lemma, ciliate along keels, and apex rounded or emarginate		(16)
+	Lemma with straight awn or awnless; palea slightly shorter to slightly longer than lemma		(52)
16 (15)	Glumes usually slightly shorter than or equaling first lemma, 5–7-veined		(17)
+	Glumes much shorter than first lemma, (1–)3–5-veined; if glumes only slightly shorter than first lemma then margin thin, scarious, membranous, or very narrowly hyaline		(25)
17 (16)	Palea oblong-obovate, much shorter than lemma.		14 E. ciliaris
+	Palea oblong, slightly shorter than or equaling lemma		(18)
18 (17)	Lemma glabrous throughout.		20 E. tibeticus
+	Lemma scabrous, pubescent, or hispidulous throughout		(19)
19 (18)	Glumes with thin margin.		15 E. canaliculatus
+	Glumes not with thin margin		(20)
20 (19)	Lemma abaxially hispidulous or laxly spinulose		(21)
+	Lemma abaxially smooth and glabrous (at middle), scabrous, puberulent, or pubescent, sometimes spinulose along veins		(22)
21 (20)	Lemma abaxially laxly spinulose, awn 2–2.5 cm; culms 30–50 tall.		16 E. sinoflexuosus
+	Lemma abaxially hispidulous, awn 2.5–4.5 cm, culms 60–100 cm tall.		17 E. gmelinii
22 (20)	Lemma abaxially scabrous, puberulent, or pubescent		(23)
+	Lemma abaxially smooth and glabrous at middle, otherwise spinulose along veins or ± puberulent		(24)
23 (22)	Lemma abaxially puberulent; culms 25–30 cm tall.		18 E. zhui
+	Lemma abaxially scabrous or pubescent, margin ciliolate; culms 30–90 cm tall.		19 E. formosanus
24 (22)	Leaf blade usually flat, thin; glume apex acuminate.		21 E. nakaii
+	Leaf blade involute, stiff; glume apex acute or with point 1–5 mm.		22 E. strictus
25 (16)	Glumes slightly shorter than first lemma, margin thin, scarious, membranous, or very narrowly hyaline		(26)
+	Glumes much shorter than first lemma, margin herbaceous		(35)
26 (25)	Glume margin scarious		(27)
+	Glume margin thin, membranous, or very narrowly hyaline		(28)
27 (26)	Culms 80–150 cm tall.		23 E. caninus
+	Culms 30–60 cm tall.		24 E. caesifolius
28 (26)	Glume margin thin; spikelets pedicellate, pedicel 0.8–9 mm		(29)
+	Glume margin membranous or very narrowly hyaline; spikelets sessile or subsessile		(30)
29 (28)	Spikelet pedicel 0.8–1.5(–2) mm.		13 E. cacuminis
30 (28)	Glume margin very narrowly hyaline		(31)
+	Glume margin membranous		(32)
31 (30)	Culms 50–100 cm tall, 3–5-noded; leaf blade flat, 2.5–8 mm wide.		26 E. antiquus
+	Culms 10–60 cm tall, 2- or 3-noded; leaf blade tightly involute, 1–4 mm wide.		27 E. burchan-buddae
32 (30)	Lemma glabrous throughout		(33)
+	Lemma puberulent or ± hispidulous		(34)
33 (32)	Glume apex with short awn; leaf blade adaxial surface villous.		28 E. serpentinus
+	Glume apex awnless, usually acute; leaf blade adaxial surface usually scabrous.		29 E. glaberrimus
34 (32)	Spikelets with 3 or 4 florets; lemma puberulent.		30 E. pseudocaninus
+	Spikelets with 4 or 5(or 6) florets; lemma hispidulous distally and near margin.		31 E. sinkiangensis
35 (25)	Glume apex usually tapering into awn 2–7 mm; palea equaling lemma		(36)
+	Glume apex acute, mucronate, or with awn less than 2 mm; palea slightly shorter to slightly longer than lemma		(43)
36 (35)	Lemma glabrous throughout		(37)
+	Lemma hirsute or hirsutulous throughout, pubescent only at base and margin, or puberulent proximally and hispidulous distally		(39)
37 (36)	Culms 15–20 cm tall; first lemma 7–9 mm; anthers yellow or purple, 1.2–2.5 mm.		32 E. jacquemontii
+	Culms (15–)40–50 cm tall; first lemma 10–12 mm; anthers black or brown, 2–5 mm		(38)
38 (37)	First lemma ca. 10 mm; anthers black, ca. 2 mm.		33 E. aristiglumis
+	First lemma 11–12 mm; anthers brown, 4–5 mm.		34 E. shouliangiae
39 (36)	Lemma pubescent only at base and margin.		37 E. altissimus
+	Lemma hirsute or hirsutulous throughout, or puberulent proximally and hispidulous distally		(40)
40 (39)	Lemma hirsutulous throughout		(41)
+	Lemma hirsute throughout, or puberulent proximally and hispidulous distally		(42)
41 (40)	Culms 1- or 2-noded; spikelets with 2 or 3 florets.		33 E. aristiglumis
+	Culms 3-noded; spikelets with 4 or 5 florets.		35 E. confusus
42 (40)	Lemma hirsute throughout; culms 60–75 cm tall; palea ciliolate along keels distally.		36 E. anthosachnoides
+	Lemma puberulent proximally, hispidulous distally; culms 20–45 cm tall; palea puberulent between keels distally.		39 E. serotinus
43 (35)	Palea equaling or slightly longer than lemma; anthers 2.5–3 mm; lemma awn (2.5–)3.5–5.5 cm		(44)
+	Palea slightly shorter than lemma; anthers 1–2 mm; lemma awn 1–3 cm		(45)
44 (43)	Leaf blade 1–2 mm wide; palea ciliate along keels.		40 E. retroflexus
+	Leaf blade 2–4 mm wide; palea glabrous along keels.		41 E. leiotropis
45 (43)	Spike somewhat nitid; lemma glabrous or sparsely puberulent abaxially.		42 E. brevipes
+	Spike not nitid; lemma pubescent, hirsutulous, or scabrous abaxially		(46)
46 (45)	Spikelets sessile or very shortly pedicellate, with 1–4(or 5) florets		(47)
+	Spikelets usually sessile, with 4–9 florets		(49)
47 (46)	Spikelets usually very shortly pedicellate, with 3 or 4(or 5) florets.		43 E. schrenkianus
+	Spikelets sessile; with 1–3(–5) florets		(48)
48 (47)	Spikelets with 1–3 florets; culms 70–150 cm tall, 5–7-noded.		37 E. altissimus
+	Spikelets with 2–5 florets; culms 40–80 cm tall, 3- or 4-noded.		38 E. laxinodis
49 (46)	Lemma hirsute throughout, especially distally and near margin, first lemma 13–14 mm.		36 E. anthosachnoides
+	Lemma ± hirsutulous or scabrous abaxially, first lemma 9–11 mm		(50)
50 (49)	Lemma ± hirsutulous abaxially, first lemma ca. 11 mm, awn 3–4 cm; spikelets with 7–9 florets.		44 E. pulanensis
+	Lemma scabrous abaxially, rarely hirsutulous, first lemma 9–11 mm, awn 1.8–3 cm; spikelets with 4–7 florets		(51)
51 (50)	Spike ± purplish, nodding, 13–15 cm; glumes oblong-lanceolate, apex acute; lemma scabrous or hirsutulous abaxially.		45 E. purpurascens
+	Spike usually glaucous green, slender and flexuose, 7–9 cm; glumes linear-lanceolate, apex usually acuminate; lemma scabrous abaxially.		46 E. tschimganicus
52 (15)	Lemma awn shorter than 7 mm or absent		(53)
+	Lemma awn more than 7 mm (but 1–35 mm E. abolinii)		(68)
53 (52)	Lemma apex truncate, with 3 teeth.		51 E. tridentatus
+	Lemma ± narrowed toward apex, without teeth		(54)
54 (53)	Palea equaling or slightly longer than lemma, apex narrowly truncate		(55)
+	Palea slightly shorter to longer than lemma, apex emarginate, rounded, or subrounded		(58)
55 (54)	Lemma ± pilose.		47 E. mutabilis
+	Lemma smooth, glabrous		(56)
56 (55)	Plants without rhizomes.		48 E. magnicaespes
+	Plants ± with rhizomes		(57)
57 (56)	First lemma ca. 10 mm, callus smooth, glabrous; anthers ca. 3 mm.		49 E. alashanicus
+	First lemma 7.8–9 mm, callus puberulent; anthers 4.5–5 mm.		52 E. elytrigioides
58 (54)	Glumes densely pubescent adaxially.		50 E. jufinshanicus
+	Glumes not as above		(59)
59 (58)	Palea 2/3–3/4 as long as lemma, subsmooth along keels.		53 E. grandis
+	Palea equaling, subequaling, or longer than lemma, ± ciliate along keels		(60)
60 (59)	Glumes 4–9-veined; palea slightly shorter to slightly longer than lemma		(61)
+	Glumes 3–5-veined; palea equaling lemma		(64)
61 (60)	Culms 30–80 cm tall; leaf blade 2–4 mm wide		(62)
+	Culms usually more than 100 cm tall; leaf blade 5–11 mm wide		(63)
62 (61)	Spikelets 1.4–1.8 cm, with 5 or 6 florets; lemma margin broadly membranous.		59 E. viridulus
+	Spikelets 1–1.4 cm, with 2–4 florets; lemma margin not membranous.		60 E. cheniae
63 (61)	Spikelets with 3–5 florets; glumes 5–7-veined; culms 100–160 cm tall.		61 E. intramongolicus
+	Spikelets with 5–9 florets; glumes 7–9-veined; culms 50–120 cm tall.		62 E. nevskii
64 (60)	Spikelets with 2 or 3 florets.		55 E. kronokensis
+	Spikelets with 3–6 florets		(65)
65 (64)	Culms ca. 100 cm tall, 4- or 5-noded.		54 E. sylvaticus
+	Culms 20–60 cm tall, 2–4-noded		(66)
66 (65)	Culms 45–60 cm tall, 2- or 3-noded.		56 E. yushuensis
+	Culms 20–45 cm tall, 2–4-noded		(67)
67 (66)	Culms ca. 45 cm tall, usually 4-noded, palea keels wingless and ciliolate.		57 E. leianthus
+	Culms 20–25 cm tall, usually 2-noded; palea keels winged and ciliate.		58 E. humilis
68 (52)	Glumes 5–7(–9)-veined, slightly shorter or longer than lemma		(69)
+	Glumes (2 or)3–5-veined, at least proximal glume 3-veined, usually much shorter than lemma, or if subequaling lemma then apex shortly awned		(76)
69 (68)	Glumes (especially distal one) longer than lemma		(70)
+	Glumes (especially proximal one) slightly shorter than lemma		(72)
70 (69)	Spike somewhat lax; palea shorter than lemma; anthers 3–7 mm.		81 E. abolinii
+	Spike dense, secund; palea subequaling lemma; anthers 2.5–3 mm		(71)
71 (70)	Glume margin membranous; lemma scabrous or appressed setose.		82 E. fedtschenkoi
+	Glume margin not membranous; lemma pubescent.		83 E. platyphyllus
72 (69)	Spikelets pedicellate, pedicel 1–2.5 mm.		85 E. magnipodus
+	Spikelets sessile		(73)
73 (72)	Lemma ± glabrous abaxially, margin narrowly membranous.		84 E. shandongensis
+	Lemma puberulent, pilose, or ± hirsutulous abaxially, margin not membranous		(74)
74 (73)	Lemma margin ciliate.		86 E. pendulinus
+	Lemma margin not ciliate		(75)
75 (74)	Glume margin scarious; leaf blade abaxial surface glabrous or scabrous, adaxial surface scabrous or pubescent.		87 E. komarovii
+	Glume margin not scarious; leaf blade both surfaces pilose or scabrous.		88 E. tianschanigenus
76 (68)	Glumes always and lemma sometimes with membranous or scarious margin		(77)
+	Glumes and lemma without membranous or scarious margin		(85)
77 (76)	Glumes and lemma with membranous or scarious margin		(78)
+	Glumes with membranous margin; lemma without such margin		(79)
78 (77)	Lemma glabrous to hispidulous, margin membranous.		63 E. kamoji
+	Lemma hirsutulous proximally and distally, subglabrous at middle, long ciliate near margin, margin broadly scarious.		64 E. hybridus
79 (77)	Culms 50–60 cm tall, 2- or 3-noded		(80)
+	Culms 60–100 cm tall, 4–7-noded		(81)
80 (79)	Glumes 5–6 mm; lemma awn 5–10 mm; anthers black.		65 E. curtiaristatus
+	Glumes 9–12 mm; lemma awn 12–15 mm; anthers yellow.		66 E. scabridulus
81 (79)	Spikelets 3.5–4.5 cm, with 5–10 florets.		67 E. yangiae
+	Spikelets to 2 cm, with 3–9 florets		(82)
82 (81)	Spikelets ± pedicellate; glumes oblong-lanceolate; palea scabrous along keels distally.		68 E. dolichatherus
+	Spikelets sessile; glumes narrowly lanceolate; palea ± ciliate along keels		(83)
83 (82)	Glumes and lemma usually smooth, glabrous, rarely scabrous along veins.		70 E. calcicola
+	Glumes and lemma hirsute or villous		(84)
84 (83)	Glumes lanceolate, subequal, 5–6 mm, 2-veined, hispidulous along veins; lemma densely villous abaxially.		71 E. trichospiculus
+	Glumes oblong-lanceolate, hirsute, proximal one 5–6.5 mm, 3- or 4-veined, distal one 6.5–7.5 mm, 4- or 5-veined; lemma usually densely pubescent proximally, scabrous-ciliate distally.		69 E. tenuispicus
85 (76)	Lemma ± puberulent abaxially		(86)
+	Lemma smooth or scabrous abaxially		(89)
86 (85)	Spikelets 12–16 mm, with 3–5 florets		(87)
+	Spikelets 9–12 mm, with 2 or 3 florets		(88)
87 (86)	Glumes oblong-lanceolate, 7–10 mm; lemma awn 10–18 mm.		72 E. sinicus
+	Glumes lanceolate, 2–5 mm; lemma awn 6–8 mm.		74 E. caianus
88 (86)	Culms usually 2-noded; glume apex acuminate.		76 E. hongyuanensis
+	Culms 5–7-noded; glume apex with awn 1.5–3 mm.		75 E. debilis
89 (85)	Lemma callus glabrous or subglabrous.		78 E. angustispiculatus
+	Lemma callus distinctly hirsute		(90)
90 (89)	Spikelets with 2 or 3 florets; lemma callus hairs 1–3 mm.		73 E. puberulus
+	Spikelets with 4–8 florets; lemma callus hairs 4–10 mm		(91)
91 (90)	Lemma callus hairs 6–10 mm.		77 E. barbicallus
+	Lemma callus hairs 4–6 mm		(92)
92 (91)	Leaf blade adaxial surface scabrous; lemma scabrous abaxially.		79 E. hondae
+	Leaf blade adaxial surface pubescent; lemma smooth and glabrous abaxially.		80 E. alienus