1	Fruits annual (maturing at end of 1st season); if fruits not available, key as if biennial.		(2)
+	Fruits biennial (maturing at end of 2d season) except in Q. agrifolia, Q. emoryi, Q. hypoleucoides, and Q. pumila.		(6)
2 (1)	Leaf blade abaxially glabrous except for tufts of tomentum in vein axils or at base.		(3)
+	Leaf blade abaxially uniformly pubescent or tomentose, sometimes glabrate.		(4)
3 (2)	Leaf blade distinctly convex, adaxially rugose; California.		2 Quercus agrifolia
+	Leaf blade planar, adaxially not rugose; Arizona to w Texas.		4 Quercus emoryi
4 (2)	Leaf blade less than 3 times as long as wide; nut ovoid or conic, 15–35 mm; California.		2 Quercus agrifolia
+	Leaf blade more than 3 times as long as wide; nut globose or oblong, 9–15 mm; Arizona and east.		(5)
5 (4)	Leaf blade abaxially tawny or white-tomentose; cup covering 1/3 nut or less; Arizona to w Texas.		6 Quercus hypoleucoides
+	Leaf blade abaxially glabrate or gray- to brown-pubescent; cup covering 1/3–2/3 nut; Mississippi to North Carolina.		16 Quercus pumila
6 (1)	Evergreen trees or shrubs; leaf blade adaxially noticeably rugose, margins entire or spinose, strongly revolute, abaxially densely tawny or white-tomentose		6 Quercus hypoleucoides
+	Leaf blade 5–11-lobed with more than 10 awns.		(77)
7	Petiole less than 10 mm.		(8)
+	Petiole more than 10 mm.		(44)
8 (7)	Leaf blade more than 4.5 times as long as wide.		(9)
+	Leaf blade less than 4.5 times as long as wide.		(12)
9 (8)	Petiole glabrous.		14 Quercus phellos
+	Petiole pubescent.		(10)
10 (9)	Low shrubs.		16 Quercus pumila
+	Trees.		(11)
11 (10)	Leaf blade narrowly lanceolate, abaxially glabrous or with tufts of tomentum at base; sc Arizona.		5 Quercus viminea
+	Leaf blade elliptic or ovate, abaxially uniformly pubescent or tomentose; e Texas to North Carolina.		11 Quercus incana
12 (8)	Leaf margins entire or merely spinose.		(13)
+	Leaf margins shallowly or deeply lobed, not merely spinose.		(32)
13 (12)	Abaxial leaf surface uniformly pubescent or tomentose.		(14)
+	Abaxial leaf surface glabrous or sparingly pubescent.		(19)
14 (13)	Leaf blade convex, adaxially pubescent or tomentose.		2 Quercus agrifolia
+	Leaf blade planar, adaxially essentially glabrous.		(15)
15 (14)	Leaf blade more than 2.5 times as long as wide. 16. Low shrubs; leaf margins revolute.		(16)
+	Leaf blade less than 2.5 times as long as wide.		(18)
16 (15)	Low shrub; leaf margins revolute		16 Quercus pumila
+	Trees; leaf margins not revolute.		(17)
17 (16)	Petioles and twigs pubescent; inner surface of cup uniformly pubescent.		11 Quercus incana
+	Petioles and twigs glabrous; inner surface of cup glabrous or with only ring of hairs around nut scar.		17 Quercus imbricaria
18 (15)	Leaf blade widest distal to middle, apex broadly obtuse to rounded; e Texas to Georgia.		23 Quercus arkansana
+	Leaf blade widest at or proximal to middle, apex acute; North Carolina to Maine.		25 Quercus ilicifolia
19 (13)	Leaf blade distinctly convex, adaxially rugose.		(20)
+	Leaf blade planar, not adaxially rugose.		(21)
20 (19)	Apex of leaf blade blunt to attenuate; nut more than 15 mm; California.		2 Quercus agrifolia
+	Apex of leaf blade obtuse or rounded; nut less than 15 mm; Florida.		19 Quercus inopina
21 (19)	Trees or shrubs evergreen (often tardily deciduous in Q. laurifolia, Q. hemisphaerica, and Q. nigra).		(22)
+	Trees deciduous (often tardily deciduous in Q. laurifolia, Q. hemisphaerica, and Q. nigra).		(28)
22 (21)	Twigs pubescent.		(23)
+	Twigs glabrous.		(25)
23 (22)	Nut 21–44 mm; California.		1 Quercus wislizeni
+	Nut less than 20 mm; Arizona and east.		(24)
24 (23)	Base of leaf blade cuneate to rounded; Mississippi to South Carolina.		18 Quercus myrtifolia
+	Base of leaf blade cordate; Arizona to w Texas .		4 Quercus emoryi
25 (22)	Leaf blade widest near apex.		15 Quercus nigra
+	Leaf blade widest at or proximal to middle.		(26)
26 (25)	Leaf blade rarely 3 times as long as wide; nut 21–44 mm; California.		1 Quercus wislizeni
+	Leaf blade commonly more than 3 times as long as wide; nut 8–16 mm; e Texas to Virginia.		(27)
27 (26)	Leaf blade leathery, base obtuse or rounded, apex acute or acuminate; trees on dry, sandy uplands.		13 Quercus hemisphaerica
+	Leaf blade thin, base attenuate or cuneate, apex obtuse or rounded; trees on low, wet flood plains and bottoms.		12 Quercus laurifolia
28 (21)	Twigs pubescent.		(29)
+	Twigs glabrous.		(30)
29 (28)	Leaf blade widest distal to middle, apex broadly obtuse to rounded; e Texas to Georgia.		23 Quercus arkansana
+	Leaf blade widest proximal to middle, apex acute or long- attenuate; w Texas.		8 Quercus robusta
30 (28)	Leaf blade widest near apex.		15 Quercus nigra
+	Leaf blade widest at or proximal to middle.		(31)
31 (30)	Leaf blade leathery, base obtuse or rounded, apex acute or acuminate; trees on dry, sandy uplands.		13 Quercus hemisphaerica
+	Leaf blade thin, base attenuate or cuneate, apex obtuse or rounded; trees on low, wet flood plains and bottoms.		12 Quercus laurifolia
32 (12)	Terminal buds 6–12 mm.		(33)
+	Terminal buds 2–6 mm.		(35)
33 (32)	Twigs glabrous.		15 Quercus nigra
+	Twigs pubescent.		(34)
34 (33)	Leaf blade widest near middle, base attenuate to acute, blade decurrent; margin of cup involute.		22 Quercus laevis
+	Leaf blade widest near apex, base rounded to cordate, blade not decurrent; margin of cup not involute.		24 Quercus marilandica
35 (32)	Twigs pubescent.		(36)
+	Twigs glabrous.		(39)
36 (35)	Apex of leaf broadly obtuse to rounded; e Texas to Long Island.		(37)
+	Apex of leaf acute to attenuate; w Texas.		(38)
37 (36)	Terminal buds glabrous or only ciliate on scale margins.		23 Quercus arkansana
+	Terminal buds uniformly pubescent.		24 Quercus marilandica
38 (36)	Base of leaf blade subcordate to broadly obtuse, awns usually fewer than 10.		8 Quercus robusta
+	Base of leaf blade rounded to cuneate, awns usually more than 10.		10 Quercus gravesii
39 (35)	Leaf blade widest distal to middle.		(40)
+	Leaf blade widest at or proximal to middle.		(41)
40 (39)	Apex of leaf blade obtuse to rounded or blunt.		15 Quercus nigra
+	Apex of leaf blade oblong or acute.		27 Quercus georgiana
41 (39)	Petiole rarely more than 5mm; margins of leaf blade rarely with more than 4 awns; trees evergreen or tardily deciduous.		13 Quercus hemisphaerica
+	Petiole commonly more than 5 mm; margins of leaf blade often with more than 4 awns; trees deciduous.		(42)
42 (41)	Mature leaf blade abaxially with conspicuous (readily discernible to naked eye) tufts of tomentum in vein axils; bark gray to light brown, scaly; Alabama to South Carolina.		27 Quercus georgiana
+	Mature leaf blade abaxially with minute (often detectable only with magnification) tufts of tomentum in vein axils (or such tufts absent); bark brown to black, roughly furrowed; w Texas.		(43)
43 (42)	Base of leaf blade subcordate to broadly obtuse, awns usually fewer than 10.		8 Quercus robusta
+	Base of leaf blade rounded to cuneate, awns usually more than 10.		10 Quercus gravesii
44 (7)	Leaf margins entire or spinose or with 3–7 lobes separated by shallow (less than 1/3 distance to midrib) sinuses; if lobed, each lobe generally with single awn.		(45)
+	Leaf margins with 3–11 lobes separated by deep (more than 1/3 distance to midrib) sinuses; lobes generally with 2 or more awns.		(61)
45 (44)	Leaf blade abaxially pubescent to tomentose.		(46)
+	Leaf blade abaxially glabrous except for tufts of tomentum in vein axils, especially along midrib.		(52)
46 (45)	Plants evergreen; California or w Texas.		(47)
+	Plants deciduous; e Texas to New England.		(48)
47 (46)	Leaf blade convex; California.		2 Quercus agrifolia
+	Leaf blade planar; w Texas.		9 Quercus tardifolia
48 (46)	Leaf blade 2.5–4 times as long as wide; twigs glabrous.		17 Quercus imbricaria
+	Leaf blade rarely as much as 2.5 times as long as wide; twigs pubescent.		(49)
49 (48)	Terminal buds uniformly pubescent, generally exceeding 5 mm.		(50)
+	Terminal buds glabrous or hairy only at apex, rarely as much as 5 mm.		(51)
50 (49)	Petiole mostly more than 20mm; tips of cup scales appressed..		20 Quercus falcata
+	Petiole rarely as much as 20 mm; tips of cup scales loose, especially at cup margin.		24 Quercus marilandica
51 (49)	Apex of leaf blade broadly obtuse or rounded, margins entire or with 2–3 rounded lobes; e Texas to Georgia.		23 Quercus arkansana
+	Apex of leaf blade acute or obtuse, margins always with 3–4 acute lobes; North Carolina to Maine.		25 Quercus ilicifolia
52 (45)	Leaf blade commonly more than 3 times as long as wide.		7 Quercus graciliformis
+	Leaf blade rarely 3 times as long as wide.		(53)
53 (52)	Leaf blade convex, adaxially rugose.		2 Quercus agrifolia
+	Leaf blade planar, not adaxially rugose.		(54)
54 (53)	Plants evergreen; California.		1 Quercus wislizeni
+	Plants deciduous; w Texas and east.		(55)
55 (54)	Leaf blade widest distal to middle.		(56)
+	Leaf blade widest at or proximal to middle.		(58)
56 (55)	Twigs glabrous.		27 Quercus georgiana
+	Twigs pubescent.		(57)
57 (56)	Terminal buds uniformly pubescent.		24 Quercus marilandica
+	Terminal buds glabrous or at most ciliate on scale margins.		23 Quercus arkansana
58 (55)	Leaf blade usually with more than 10 awns.		(59)
+	Leaf blade usually with fewer than 10 awns.		(60)
59 (58)	Petiole less than 25 mm; bark black and furrowed; cup less than 15mm wide; w Texas.		10 Quercus gravesii
+	Petiole more than 25mm; bark gray or dark gray with wide shiny ridges separated by shallow fissures; cup more than 15 mm wide; Oklahoma to Nova Scotia.		32 Quercus rubra
60 (58)	Base of leaf blade subcordate to broadly obtuse; cup deeply cup-shaped, 6–9 mm high; w Texas.		8 Quercus robusta
+	Base of leaf blade cuneate to obtuse; cup shallowly saucer- shaped, 4–6mm high; Alabama to South Carolina.		27 Quercus georgiana
61 (44)	Leaf blade abaxially uniformly pubescent or tomentose.		(62)
+	Leaf blade abaxially glabrous or with a few scattered hairs, not uniformly pubescent.		(65)
62 (61)	Nut oblong to broadly ellipsoid, 21–34 mm; tips of cup scales loose; California to Oregon.		3 Quercus kelloggii
+	Nut ovoid or subglobose, 9–16 mm; tips of cup scales appressed; Texas and east.		(63)
63 (62)	Base of leaf blade rounded or U-shaped, terminal lobe much longer than lateral lobes.		20 Quercus falcata
+	Base of leaf blade cuneate to truncate, terminal lobe rarely exceeding lateral lobes.		(64)
64 (63)	Trees; terminal buds 4–9 mm, light reddish brown, uniformly puberulent		21 Quercus pagoda
+	Shrubs; terminal buds 2–4.5 mm, dark reddish brown, puberulent only at apex.		25 Quercus ilicifolia
65 (61)	Terminal buds uniformly pubescent.		(66)
+	Terminal buds glabrous or pubescent only on distal 1/2.		(67)
66 (65)	Leaf base attenuate or acute, blade decurrent; margin of cup involute.		22 Quercus laevis
+	Leaf base obtuse to truncate, blade not decurrent; margin of cup not involute.		35 Quercus velutina
67 (65)	Terminal buds silvery or reddish pubescent on distal 1/2.		(68)
+	Terminal buds glabrous or with only a few reddish hairs at apex.		(71)
68 (67)	Base of leaf blade attenuate or acute, decurrent; petiole commonly less than 20 mm; margin of cup involute.		22 Quercus laevis
+	Base of leaf blade obtuse to truncate, not decurrent; petiole commonly more than 20 mm; margin of cup not involute.		(69)
69 (68)	Leaf blade adaxially dull green; sinuses usually extending less than 1/2 distance to midrib, lobes acute to oblong.		32 Quercus rubra
+	Leaf blade adaxially glossy green; sinuses usually extending more than 1/2 distance to midrib, lobes distally expanded.		(70)
70 (69)	Cup turbinate to hemispheric, scales with broad glossy base, scale margins often strongly concave; nut ovoid to subglobose, with 1 or more concentric rings of pits at apex.		33 Quercus coccinea
+	Cup deeply cup-shaped to turbinate, scales pubescent with straight or slightly concave margins; nut ellipsoid to ovoid, without rings of pits at apex.		34 Quercus ellipsoidalis
71 (67)	Leaf blades mostly wider than long.		31 Quercus acerifolia
+	Leaf blades mostly longer than wide.		(72)
72 (71)	Twigs and/or terminal buds yellowish gray, gray, or grayish brown.		(73)
+	Twigs and terminal buds brown to dark reddish brown or red.		(75)
73 (72)	Mature leaf blade abaxially glabrous or with minute (often detectable only with magnification) tufts of tomentum in vein axils.		29 Quercus buckleyi
+	Mature leaf blade abaxially with conspicuous (readily discernible to naked eye) tufts of tomentum in vein axils.		(74)
74 (73)	Cup with thin (less than 1.5mm in cross section) walls, deeply goblet-shaped, covering 1/3–1/2 nut, inner surface pubescent.		28 Quercus texana
+	Cup with thick (more than 1.5mm in cross section) walls, saucer- or cup-shaped, covering 1/4–1/3 nut, inner surface glabrous or with ring of hairs around scar.		30 Quercus shumardii
75 (72)	Leaf blade abaxially with conspicuous (readily discernible to naked eye) tufts of tomentum in vein axils.		(76)
+	Leaf blade abaxially glabrous or with minute (often detectable only with magnification) tufts of tomentum in vein axils.		(78)
76 (75)	Leaf blade 3–5-lobed with fewer than 10 awns.		27 Quercus georgiana
+	desc needed
77 (6)	Cup deeply goblet- shaped, covering 1/3– 1/2 nut; nut broadly ovoid to broadly ellipsoid, rarely less than 16mm.		28 Quercus texana
+	Cup shallowly saucer- shaped, covering less than 1/3 nut; nut globose or ovoid, rarely more than 16mm.		26 Quercus palustris
78 (75)	Cup generally more than 12 mm high; cup scales more than 4mm, attenuate or acuminate to acute with loose tips, especially at cup margin; California to Oregon.		3 Quercus kelloggii
+	Cup rarely as much as 12 mm high; cup scales less than 4mm, acute to obtuse with tightly appressed tips; wTexas and east.		(79)
79 (78)	Leaf blade adaxially dull green, abaxially pale green or glaucous; cup 18–30 mm wide; Oklahoma to Nova Scotia.		32 Quercus rubra
+	Leaf blade adaxially shiny or glossy, abaxially light green or coppery green; cup 7–18 mm wide; Texas to Oklahoma.		(80)
80 (79)	Petiole more than 20 mm; leaf lobes usually distally expanded; c Texas to Oklahoma.		29 Quercus buckleyi
+	Petiole usually less than 20 mm; leaf lobes acute; w Texas.		10 Quercus gravesii