2 1 Areoles bearing glochids; stems jointed, cylindric or flattened, not ribbed, not bearing prominent tubercles.  3

Areoles not bearing glochids; stems cylindric, sometimes bearing joints, ribs or prominent tubercles. 16

3 2  Joints cylindric; spines sheathed when young: Chollas 4

Joints flattened (pads), spines not sheathed 9

4 3  Lateral joints ¼” in diameter, 1-3” long; Plant bushy 

Lateral joints ½” or more in diameter, over 3” long 5

5 4 Branchlets ¾” or more in diameter, bearing elongate, low tubercles    6

Branchlets to ½” in diameter, smooth or bearing obscure tubercles; plant arborescent at maturity

6 5 Branches in whorls; plants arborescent 

Branches not in whorls; plants sometimes arborescent 7

7 6 Plants arborescent, much branched; spines straw-colored 8

Plants sprawling shrubs, loosely branched; spines dark to light, but not straw-colored

8 7 Plants to 6’ tall; terminal joints short, very easily dislodged; fruits not in chains
 

Plants to 12’ tall; terminal joints longer, not as easily dislodged; fruits persisting in chains (variety with fewer and shorter spines on more prominent tubercles is mammillata

9 3 Joints broad, flattened, alternate or irregularly arranged; Prickly Pears 10
Joints narrow, flattened, whorled 

10 9 Joints 3-4 times longer than wide, tapering to a long slender tip

Joints not more than twice as long as wide, orbicular to obovate 11

11 10  Central spines present, stout, whitish or yellowish

Central Spines, if present, not stout, yellowish to reddish 12

12 11 Plants arborescent, with distinct trunks 13

Plants shrubs, not with distinct trunks 15

13 12 Pads very thick; glochids few, scarcely visible; areoles widely spaced
 

Pads less than ¾” thick; glochids numerous, obvious; areoles closely spaced 14

14 13 Pads about ½” thick, green to blue-green

Pads about ¼” thick, green turning purplish during cold or dry seasons

15 12 Plants to 1 ½’ tall, mostly one joint high; joints obovate, gray, wrinkled, with abundant red glochids

Plants to 4’ tall, several joints high; joints oblong to orbicular, green, velvety, with abundant red to white glochids 

16 2 Stems weak, arching or trailing, with long slender joints 17

Stems erect 20

17 16 Stems gray, angled with 3-6 prominent longitudinal ribs bearing blackish spines less than 1/8^” long

Stems green (or purplish), ribbed but not angled; spines white or yellow to gray, more than ¼” long 1 ??

18 17 Spines ½” (or less) long; ribs not prominent

Spines 1” long or longer; ribs prominent 19

19 18 Older stems approximately 3” in diameter, turning red during cold or dry periods, branching near the base

Older stems approximately 2” in diameter, green, branching above the base

20 16 Stems columnar, 6’ or more tall, ribbed; spines terete, straight (in one form absent) 21

Stems less than 6’ tall, or if more, then at least certain spines definitely curved and flattened 23

21 20 Plant branching well above the constricted base

Plant branching near the unconstricted base, sometimes also above 22

22 21 Ribs numerous, 12-17; spines uniform throughout plant

Ribs fewer, 5-7; spines not uniform throughout plant; mature branch tips with areoles bearing numerous flexuous spines(or spines absent; areoles few; rounded protruberences forming irregular ribs in forma monstrosus) 

23 20 Plants with prominent tubercles not arranged in longitudinal ribs 24

Plants with longitudinal ribs 25

24 23 Tubercles grooved above; central spine straight

Tubercles not grooved; central spine hooked

25 23 Spines straight or slightly curved, but not hooked or distinctly twisted 26

At least some of the spines hooked or distinctly twisted 28

26 25 Plants cylindric, branching mostly at or below soil line

Plants globose, solitary or branched at base or above 27

27 26 Spines terete, dark-colored; plants often branched above base, apex not depressed, not woolly

Spines flattened, golden yellow; plants solitary or branched at base; apex depressed, woolly

28 25 Plants nearly as wide as tall; central spines not twisted, sometimes hooked 
 

Plants much taller than wire; central spines twisted, often hooked

29 1 Plants palms or palm-like (some without trunks) 30

Plants not palm-like 53

30 29 Leaves palmately veined;  Fan Palms 31

Leaves pinnately veined; Feather Palms 43

31 30 Trunks clustered, usually dward to 10’ tall, often hidden in foliage 32

Trunks solitary, of various heights 33

32 31 Blades deeply divided into 5-10 segments, almost as leaflets (appearing like dwarf bamboo); petioles not armed or irregularly so

Blades not deeply divided to appear as leaflets; petioles distinctly armed with teeth

33 31 Palms dwarf; trunk to 4’ tall; blades deeply divided into two equal parts, each with minor divisions; petioles not armed

Palms not dwarf; trunks to 10’ or more tall; blades not deeply divided into two parts; petioles armed or not 34

34 33 Midvein decidedly curled downward and backward; petiole not with marginal teeth 35

Midvein little or not at all curled downward and backward; petioles with or without marginal teeth  36

35 34 Leaf blades to 6’ across; inflorexcence shorter than petiole; fruit about ½” in diameter

Leaf blades to 4’ across; inflorescence longer than petiole; fruit about 3/8” in diameter. 

36 34 Very long, stout spines terminating stiff network of old leaf sheaths.

No stout spines terminating old leaf sheaths 37

37 36 Leaf blades with sharply drooping segments Fountain Palms 38

Leaf blades not with sharply drooping segments 39

38 37 Trees to 60’ tall; leaves soft green; petioles armed.

Trees to 30’ tall; leaves bright shiny green; petioles sometimes armed.  

Petiole smooth (or with few small teeth at base) 

Petiole with marginal teeth 40

Petiole with very fine teeth; trunk with very many hair-like fibers.

Petiole with coarse teeth; trunk not with very many hair-like fibers (though some may be present) 4 ??

Leaves blue-glaucous. 

Leaves green or gray-green 42

42 41 Trunks short to medium height, stout, about 2’ or more in diameter at middle; blades very filiferous at maturity

Trunk tall, slender, about 1’ in diameter at middle; blades little filiferous.

Leaves flat or folded lonitudinally in bud; pinnae not with revolute margins 44

Leaflets not with a prominent midvein Dioon edule

Lower pinae not developed into spines 48

Trunks solitary, not dwarf 47

Leaves white floccose in interrupted lines on ribs beneath

Leaves not white floccose beneath 

Trees slender to 100’ tall, with a rather dense crown of green to bluish green leaves, often glaucous; fruit cylindric, 1-2” long, edible; seed more than 3 times longer than wide

Trees stout, to 60’ tall, with a dense crown of green to light green leaves;, fruit about ¾” long, not considered edible; seed less than 3 times longer than wide

48 44 Pinnae tips erose (jagged); leaflets rigid, many-veined, broadened at apex.

Pinnae tips pointed, not erose; leaflets various 49

49 48 Leaves blue-glaucous, arching, petiole spiny at base.

Leaves green; petiole not spiny 50

50 49 Shrubby trees to 8’ tall; pinnae to 20 pairs in number 

Trees 20-50 feet or more tall; pinae many, 40 pairs or more 51

51 50 Petiole fibrous shaggy 

Petiole not fibrous shaggy 52

52 51 Pinnae with lateral veins prominent above, chaffy on midvein and margins beneath, at least when young; stems branching at maturity; leaf rachis yellow to red beneath. 
 

Pinnae with lateral vines prominent beneath, coarsely chaffy on only midvein beneath; leaf rachis slightly grayish beneath; stems not branching.

53 29 Plants grasses (including bamboos) or grass-like; leaves parallel veined, ensheathing stems 54

Plants not grass-like; leaves various but not parallel veined and ensheathing stems. 67

54 53 Plants aquatic or semiaquatic; leaves strongly ascending; Cattails

Plants terrestrial; leaves not strongly ascending 55

55 54 Culms(stems) terete, jointed, or various heights; all leaf sheaths with blades, these sometimes deciduous 56

Culms angled slightly, but not jointed, 2-4' tall, stout, bearing many long, firm, spreading leaves at the apex (like umbrella ribs); basal leaf sheaths bladeless

56  55 Blades much broader than the sheath, stalked, deciduous from the joint at sheath; sheaths sometimes persistent Bamboos 57

Blades narrower than or as broad as the sheaths, not stalked; blades and sheaths persistent 65

57 56 Culms flattened on one side above the node 58

Culms terete throughout 60

58 57 Culms becoming black

Culms becoming yellow or golden 59

59 58 Culms flattened on one side above node

Culms grooved on one side above node

60 57 Culms to about 3' tall, from running rhizomes, not clumping 61

Culms 5' or more tall, sometimes in dense clumps 62

61 60 Internodes solid, short; culms to 1 foot tall, purplish

Internodes hollow, long; culms to 3' tall(leaves green or variegated)

62 60 Rhizome internodes with many scattered roots developing; culms with several branches at a node; sheath bristles stiff, scabrous 63

Rhizome internodes with a single band or row of roots developing; culms with one or two branches at a node; sheath bristles flexuous, not scabrous

63 62 At least some internodes swollen in the middle (intensifies if pot-bound)

Internodes not swollen in the middle 64

64 63 Stems to 60' or more tall, 2-4" in diameter at maturity, deep green

Stems to 35' tall, 1" in diameter, often striped green, yellow or pink

65 56 Leaf margins finely serrate (serrulate) 66

Leaf margins entire, smooth

66 65 Culms 18-36" tall, less than 1/8" in diameter, scabrous below the inflorescence; inflorescence narrow, to 12" long

 
Culms 4-20' tall, about 1/4" or more in diameter, glabrous throughout; inflorescence open, plume-like, to 2' long Cortaderia selloana

67 53 Plants yuccas or yucca-like, often scapose; leaves in a rosette, basal or atop a trunk (occasionally well distributed along trunk in young plants), often linear, sometimes succulent 68

Plants neither scapose nor with a rosette of leaves 77

68 67 Leaves with marginal prickles 69

Leaves not with marginal prickles, but sometimes finely serrate (serrulate) 71

69 68 Leaves very succulent, usually spotted with a lighter color; no fibers in center of leaf; basal rosette to 2' in diameter Aloe spp.

Leaves not succulent or succulent fibers in the center of the leaf; basal rosette usually larger than 2' in diameter 70

70 69 Blades thin, to 1" wide, about 3' long, tapering to long foliaceous tips; margins bearing numerous tiny recurved prickles

Blades thick, succulent, with strong central fibers, to 6" or more wide, about 4' long, with stout spines at tips; margins bearing relatively few but large prickles (variety with white or yellow margined leaves is marginata)

71 68 Leaf margins serrulate to entire 72

Leaf margins filiferous 75

72 71 Leaves rigid, dagger-like 73

Leaves flexible, lower leaves recurved or drooping 74

73 72 Leaves to about 8" long, about 1/2" wide; arborescent, much branched Yucca brevifolia

Leaves to about 1' or more long, about 3/4" or more wide; sometimes arborescent, little branched Yucca aloifolia

74 72 Arborescent, stems often with swollen bases; leaf margins sharply serrate Yucca elephantipes

Stems short, not noticeably swollen at bases; leaf margins entire or irregularly serrulate to undulate Yucca recurvifolia

75 71 Plants at maturity with trunks; leaf blades flat, narrow, with many fine fibers Yucca elata

Plants at maturity not with trunks, or if so, then not erect; leaf blades concave, narrow to broad, with few and coarse fibers 76

76 75 Leaf blades more than 1" wide, to 2' long; inflorescence rigid, dense, little exceeding the foliage Yucca baccata

Leaf blades to 3/4": wide to 4' long; inflorescence limber, open, greatly exceeding the foliage Hesperaloe parviflora

77 67 Leaves sessile, bladeless, appearing needle-like or scale-like (appressed flattened or subulate) or bristle-like; leaves present during the growing season 78

Leaves sessile or not, blades flattened, sometimes with revolute margins; leaves present or absent during the growing season 97

78 77 Leaves fascicled, needle-like or filiform 79

Leaves not fascicles; needle-like, scale-like or bristle-like 84

79 78 Vines or shrubs, armed along main axes; leaves (actually modified stems called cladodes) to 1" long 80

Trees, unarmed; leaves 1" or more long 81

80 79 Vines or trailing shrubs, branchlets much flattened, triangular in outline, fern-like; cladodes of branchlets mostly about 1/4" long Asparagus plumosus

Upright shrubs, branchlets not flattened; cladodes of branchlets mostly 1/2" or more long Asparagus retrofractus

81 79 Fascicles not sheathed; needles falling singly Cedrus deodara

Fascicles sheathed; needles falling in clusters Pines 82

82 81 Needles 2 per fascicle, 2-6" long; sheaths to 1/2" long 83

Needles 3 per fascicle, 8-12" long; sheaths to 3/4" long Pinus canariensis

83 82 Sheath ending in two long filaments; cones deciduous Pinus thurberiana

Sheath not ending in two long filaments; cones persistent Pinus halepensis

84 78 Branchlets appearing jointed, internodes longer than leaves 85

Branchlets not appearing jointed, internodes shorter than the leaves 87

85 84 Shrubs; branchlets stout, ascending; leaves opposite, shredding at maturity Ephedra fasciculata

Trees; branchlets fine, flexuous; leaves alternate or whorled, minute 86

86 85 Leaves alternate, reduced to mere obtuse protuberances Tamarix aphylla

Leaves in whorls of 5-9, acute, fused below Casuarina cunninghamiana

87 84 Leaves alternate 88

Leaves opposite or whorled 89

88 87 Major branches alternate; branchlets fine, shrubs 88a

Major branches whorled; branchlets not fine, slightly or not glaucous; trees; leaves more than 1/3' long Araucaria heterophylla

Shrubs to 3' tall; leaves 1" or more long Grevillea noelli

89 87 Branchlets flattened, arranged in vertical planes Thuja orientalis

Branchlets not flattened, or if so, then not arranged in vertical planes 90

90 89 Trees; leaves scale-like, not subulate; cones woody, persistent, dehiscent, with many seeds under peltate scales Cypresses 91

Trees or shrubs; leaves all scale-like or all subulate or mixed; cones berry-like, indehiscent, scales fused with 1-few seeds; Junipers 92

91 90 Trees pyramidal to columnar Cupressus sempervirens

Trees with spreading branches, not pyramidal, not columnar (smooth, red-barked form with exfoliating bark often called C. glabra) Cupressus arizonica

92 90 Leaves with a strong disagreeable odor when crushed Juniperus sabina

Leaves not with a disagreeable odor when crushed 93

93 92 Leaves all( or nearly all) subulate 94

Leaves of two kinds, scale-like and subulate, or all scale-like 95

94 93 Leaves opposite (in whorls of 3 on vigorous new growth); low spreading or trailing shrubs, grayish green turning purplish in winter Juniperus horizontalis

Leaves mostly in whorls of 3; trees or shrubs, sometimes creeping; green or blue-green (includes J. procumbens) Juniperus chinensis

95 93 Leaves all or nearly all scale-like, obtuse to acute, opposite, or if also with subulate leaves, these in whorls of 3, at least on older branch axes; berry-like cone brownish, glaucous, 1/4" or more in diameter (numerous forms including cv. 'Torulosa' which has deep green clustered branchlets; cf. 'Pfitzeriana' which is shrubby with horizontally spreading branches. Juniperus chinensis

Leaves both scale-like and subulate; scale-like leaves acute to acuminate, opposite; subulate leaves mostly opposite; berry-like cone blackish, glaucous, 1/4" or less in diameter 96

96 95 Gland on lower scale leaf surface small, shorter than distance from gland to leaf apex Juniperus virginiana

Gland on lower scale leaf surface elongate, equal to or longer than distance from gland to leaf apex Juniperus scopulorum

97 77 Leaves absent because of drought conditions, but with evidence of former leaves such as leaf scars, and persisting petioles or rachises 98

Leaves evergreen or at least present during the growing season 107

98 97 Plants with spines 99

Plants not with spines, but with or without stout branches, these sometimes modified into thorns 101

99 98 Paired stipular apines present; rachises of compound leaves usually persisting, primary rachis short, ending in a sharp spine; secondary rachises 2-3 pairs, 8" or more long Parkinsonia aculeata

Spines not paired, formed from persistent petioles after loss of blade of simple leavs 100

100 99 Plant branching from near the base into many wand-like branches bearing greenish stripes or patches Fouquieria splendens

Plant with large, inverted carrot-shaped trunk, branching throughout, branches short, horizontal, not bearing greenish stripes or patches Idria columnaris

101 98 Branches stout, thorny; plants intricately branched 102

Branches neither stout nor thorny; if plant is intricately branched, then the branches are narrowly winged 105

102 102 Shrubs; branches tan, brown or gray 103

Trees; branches green 104

103 102 Plants silvery gray with abundant straight gray hairs; branches with dark sharpened tips and additional lateral thorns Condalia lycioides

Plants tan or brownish with appressed hairs; branchlets only slightly thorny, tips not darkened, not with lateral thorns Lycium exsertum

104 102 Branches yellowish green Parkinsonia microphyllum

Branches bluish green Parkinsonia florida

105 101 Stems green, woody; leaf scars alternate 106

Stems gray, brittle, only slightly woody at base (sufrutescent); leaf scars opposite Justicia californica

106 105 Plants intricately branched; branches narrowly winged, viscid-glandular Baccharis sarothroides

Plants with long, terete, wand-like branches, not viscid-glandular Spartium junceum

108 107 Plants with tendrils 109

Plants not with tendrils ( but sometimes bearing roots along the stems ) 119

109 108 Leaves compound 110

Leaves simple 115

110 109 Leaves alternate, palmately compound or trifoliate 111

Leaves opposite, compound and 3-parted, center leaflet reduced to a tendril ( sometimes leaves simple or with 2-3 non-tendril leaflets) 113

111 110 Leaflets usually 5, thin, not fleshy; tendrils ending in flattened disks Parthenocissus quinquefolia

Leaflets usually 3 or 5, fleshy; tendrils not ending in a flattened disk 112

112 111 Leaflets usually 5 Cissus hypoglauca

Leaflets 3 Cissus rhombifolia

113 110 Tendril simple; lateral leaflets obtuse to acute Clytostoma callistegioides

Tendril 3-cleft; lateral leaflets acuminate 114

114 113 Tendril sharp-clawed, not longer than the lateral ovate to lanceolate or oblanceolate leaflets Doxantha unguis-cati

Tendril not sharp-clawed, much longer than the lateral cordate-deltoid leaflets Pithecoctenium cynanchoides

115 109 Leaves heart-shaped; not lobed; margins undulate or crenate Antigonon leptopus

Leaves lobed 116

116 115 Leaf margins shallowly to deeply lobed, lobes acutely toothed or jagged; petioles not with glands Vitis vinifera

Leaf margins deeply 3-5 lobed, lobes entire or serrate; petioles with 2-4 glands 117

117 116 Leaf margins 5 lobed Passiflora caerulea

Leaf margins 3 lobed 118

118 117 Lobes entire, dull above; stem angled, not grooved Passiflora x alato-caerulea

Lobes irregularly serrate, glossy above; stem grooved Passiflora edulis

119 108 Leaves pinnately compound 120

Leaves simple (sometimes deeply lobed) 122

120 119 Leaflet margins serrate or dentate 121

Leaflet margins entire or undulate Wisteria sinensis

121 120 Leaves opposite; leaflets 9-13, pubescent beneath, dentate Campsis radicans

Leaves alternate; leaflets 5-7, glabrous beneath or very nearly so, serrate Rosa banksiae

122 119 Stems armed with thorns or spines 123

Stems not armed 125

123 122 Leaves (actually modified stems called cladodes ) linear, often fascicles; stems with spines (modified bracts) along main axes 124

Leaves ovate, acuminate, not fascicled; stems with thorns Bougainvillea spectabilis

124 123 Cladodes about 1" long, straight or nearly so, margins not noticebly crisped Asparagus densiflorus sprengeri

Cladodes about 2-3" long, often sickle-shaped (falcate), margins noticeably crisped Asparagus falcatus

125 122 Leaves opposite 126

Leaves alternate 129

126 125 Petioles bearing 2 minute glands at base of blade Vinca major

Petioles not bearing glands 127

127 126 Petioles jointed Jaminum nitidum

Petioles not jointed 128

128 127 Plants with milky sap 128a

Plants not with milky sp 128a

eaves acute to acuminate, lower lateral veins directed forward along margins; plants not with milky sap Gelsemium sempervirens

Leaves abruptly narrowed to blunt (sometimes pointed) tips, lower lateral vines not directed far forward along margins; plants usually with milky sap Trachelospermum jasminoides

Small teeth confined to bases of petioles, not borne all along stipular ridge Periploca graeca

Stipular ridge not bearing teeth (immature leaves of var. chinensis purple-tinted) Lonicera japonica

129 125 Leaf margins ( at least some of them ) palmately lobed or dissected 130

Leaf margins entire 133

130 129 Leaf margins deeply dissected; stems hirsute Ipomoea dissecta

Leaf margins lobed, not deeply dissected; stems sometimes pubescent but not hirsute 131

131 130 Leaf blades deltoid, usually shallowly 3-lobed Hedera canariensis

Leaf blades not deltoid, usually 5-lobed 132

132 131 Petioles with sessile stellate hairs only; leaf blades to 3" broad Hedera helix

Petioles with branching upright hairs; leaf blades to 6" broad; stems usually stout, often shrubby Fatshedera lizei

133 129 Plants dimorphic; vegetative stage with stems adhering flat to supporting wall, leaf blades to 1" long, cordate-ovate, inequilateral; fruiting stage with branches stiff and erect, leaf blades 2-4" long, elliptic to oblong-elliptic, inequilateral.  Vines woody, milky Ficus pumila

Plants not dimorphic; vines nearly herbaceous, not milky 134

134 133 Leaf blades thin, somewhat crinkled, with sheathing stipules Polygonum aubertii

Leaf blades fleshy and smooth, not with sheathing stipules Boussingaultia gracilis var. pseudo-basselloides

135 107 Leaves compound or so deeply divided as to appear compound 136

Leaves simple 202

136 135 Leaf margins deeply dissected and appearing pinnately compound 137

Leaves regularly compound with distinct leaflets 140

137 136 Subshrubs; leaf blades 1/2' to 1 1/2" long, pinnately divided into minute segments arranged in 4 rows; herbage aromatic when crushed 138

Trees or shrubs; leaf blades not divided into minute segments arranged in 4 rows 139

138 137 Plants silvery gray, tomentose Santolina chamaecyparissus

Plants green, glabrous Santolina virens

139 137 Trees to 150' tall; leaves alternate, leaf blades more than 6" long, with secondary lobes entire or again lobed, silky beneath, margins revolute Grevillea robusta

Shrubs to 10' tall; leaves opposite; leaf blades to 5" long, once-loved (some often unlobed), not silky beneath, margins not revolute Syringa laciniata

140 136 Leaves pinnately compound or leaflets 2 or 3 141

Leaved palmately compound, leaflets more than 3 198

141 140 Leaflets 2 (bifoliate), rachis slightly prolonged between the leaflets, leaflets confluent at bases Larrea divaricata

Leaflets more than 2 142

142 141 Leaflets 3 (trifoliate) 143

Leaflets more than 3 (occasionaly some trifoliate) 147

143 142 Petioles with recurved prickles Erythrina crista-galli

Petiole not with prickles 144

144 143 Stems armed with thorns; petioles broadly winged, jointed at base of blade Poncirus trifoliata

Stems not armed; petioles, if winged, not jointed at base of blade. 145

145 144 Leaves alternate; trees or shrubs 146

Leaves opposite; shrubs with slender branches arching to the ground Jasminum mesneyi

146 145 Trees; leaflets lanceolate, 2" or more long Rhus lancea

Shrubs; leaflets obovate, to about 1/2" long Citisus racemosus

147 142 Leaves once compound 167

Leaves more than once compound 148

148 147 Leaves three or four times compound 149

Leaves twice compound 150

149 148 Leaflets entire; petioles clasping; shrubs Nandina domestica

Leaflets serrate to dentate; petioles not clasping; trees Melia azerdarach

150 148 Leaflet margins obviously crenate, serrate or dentate 151

Leaflet margins entire ( or sometimes ciliate ) 152

151 150 Leaflets acuminate, coarsely serrate to dentate; leaves odd-pinnate, twice or thrice compound; trees unarmed Melia azerdarach

Leaflets obtuse to acute, not acuminate, finely serrate or crenate; leaves even-pinnate, once or twice compound; trees armed with large, stout, simple or branched thorns (or without thorns forma inermis ) Gleditsia triacanthos

152 150 Leaves opposite Jacaranda acutifolia

Leaves alternate 153

153 152 Petiole bearing a small gland above, located from base to between lowest primary pinnae 154

Petiole not bearing glands 159

154 153 Nodes of older branches knobby; branches often zig-zag, usually armed with stipular spines 155

Nodes not knobby; branches not noticeably zig-zag, armed or not 156

155 154 Leaves glabrous; leaflets usually more than 5 times longer than wide Prosopis glandulosa

Leaves pubescent; leaflets usually less than 5 times longer than wide Prosopis velutina

156 154 Primary leaflets 1-3 pairs; stems armed with stipular spines Ebenopsis flexicaule

Primary leaflets 4-12 pairs; stems not armed 157

157 156 Shrubs or sprawling trees; branches flattened, fern-like; stipules when present broad, leafy Lysiloma thornberi

Trees; branches not fern-like; stipules narrow, not leafy 158

158 157 Trees flat-topped; leaflet midvein submarginal; flowers pinkish, spring blooming Albizia julibrissin

Trees not flat-topped; leaflet midvein submedian; flowers white, fall-blooming Leucaena leucocephala

159 153 Primary leaflets 1-5 (-6) pairs; stipular spines present or not 160

Primary leaflets 6-many pairs; stipular spines absent 165

160 159 Primary rachis short, ending in a spine; primary leaflets 2-3 pairs, 8 inches or more long, with numerous tiny secondary leaflets; stipular spines present Parkinsonia aculeata

Primary rachis not ending in a spine; primary leaflets to 4" long 161

161 160 Main branches green or blue-green 162

Main branches dark, brownish or grayish 163

162 161 Bark of main branches yellow-green; secondary leaflets very tiny, 5-6 pairs per secondary rachis Parkinsonia microphyllum

Bark of main branches blue-green; secondary leaflets to 1/3" long, 2-3 pairs per secondary rachis Parkinsonia florida

163 161 Shrubs, not armed Calliandra tweedii

Trees or shrubs, armed 164

164 163 Primary leaflets 4-5 pairs; secondary leaflets numerous, terminal ones oblong to narrowly elliptic; stipular spines paired, straight Acacia farnesiana

Primary leaflets 1-3 pairs; secondary leaflets few, terminal ones obovate; prickles solitary, recurved Acacia greggii

165 159 Small trees; leaves large, often 1 1/2' or more long Delonix regia

Shrubs; leaves smaller, usually less than 1' long 165a

Secondary leaflets larger (about 1/4" or more long); stipules not spinescent 166

166 165 New growth not with stalked glands, not foetid; stems sometimes with prickles Caesalpinea pulcherrima

New growth with stalked glands, foetid, stems not armed Caesalpinea gilliesii

167 147 Leaves opposite 168

Leaves alternate 172

168 167 Trees; fruits samaras (dry, winged, indehiscent, one-seeded ) 169

Shrubs ( or occasionally small trees ); fruits not samaras 170

169 168 Leaflets barbellate on veins beneath, otherwise glabrous or nearly so Fraxinus uhdei

Leaflets not barbellate beneath, densely pubescent (in subspecies velutina) to glabrous (in supspecies glabra) Fraxinus pennsylvanica

170 168 Leaflets linear to narrowly lanceolate, coarsely serrate to dentate Tecoma stans

Leaflets broadly lanceolate to ovate 171

171 170 Leaflets ovate, to one inch ling, margins crenate to dentate; stems weak Tecomaria capensis

Leaflets ovate to broadly lanceolate, 2-4" long, margins serrate; stems upright Sambucus neomexicana

172 167 Leaves odd-pinnate (single leaflet at the apex of the leaf); if both even and odd pinnate leaves occur on same plant, use this choice 173

Leaves even-pinnate (paired leaflets at the apex of the leaf) 191

173 172 Upright tree like shrub with long, twining, vine-like branchlets, unarmed Wisteria sinensis

 Trees or shrubs, not with long, twining, vine-like branchlets, sometimes armed 174

174 173 Leaflet margins with 2-4 coarse basal teeth, each bearing a large gland beneath Ailanthus altissima

Leaflet margins dentate, serrate or entire, not toothed at base, not with glands beneath 175

175 174 Trees with graceful pendulous branchlets; leaflets 30 or more, linear-lanceolate, margins entire or often serrate, aromatic when crushed Schinus molle

Trees or shrubs with or without pendulous branchlets; leaflets 5-17, shapes various, sometimes aromatic when crushed 176

176 175 Leaflet margins serrate or dentate 177

Leaflet margins entire or undulate 182

177 176 Leaflets 5-11, lateral ones sessile 178

Leaflets 5-17, lateral ones short to long stalked 179

178 177 Leaflet margins coarsely dentate, dentations bristle-tipped; rachis not winged or margined Mahonia aquifolia

Leaflet margins serrate to dentate (sometimes entire), dentations or serrations not bristle-tipped; rachis winged or margined Schinus terebinthefolius

179 177 Leaflets usually 7-17, bases often inequilateral and midveins often curved; trees; stems and petioles not with prickles 180

Leaflets usually 5-7, bases sometimes inequilateral, midveins essentially straight; shrubs 181

180 179 Pith (soft tissue in center of stem) of branchlets chambered Juglans major

Pith of branchlets solid, not chambered Carya illinioensis

181 179 Stems and petioles with prickles; stipules large, fused to petiole most of their length, forming wings Rosa cathayensis

Stems and petioles rarely with prickles (if any); stipules minute, fused to petiole little of their length, not forming conspicuous wings Rosa banksiae

182 176 Plants with stipular spines (flwers white) Robinia pseudoacacia

Plants not with stipular spines 183

183 182 Leaflets and branchlets glabrous or nearly so 184

Leaflets and branchlets obviously pubescent 188

184 183 Leaflets distinctly alternate, glandular dotted Murraya paniculata

Leaflets opposite or subopposite, not glandular 185

185 184 Shrubs; branches angled or slightly winged Jasminum humile

Trees; branches terete; leaves sometimes even-pinnate 186

186 185 Leaflets 5-7, aromatic when crushed Schinus terebinthefolius

Leaflets 9-13, not aromatic when  crushed 187

187 186 Leaflets lanceolate, obtuse Pistacia terebinthus

Leaflets lanceolate, acuminate Pistacia chinensis

188 183 Shrubs or small trees; at least the terminal leaflets obovate to oblanceolate 189

Trees; leaflets oblong-ovate to lanceolate 190

189 188 Terminal leaflets to 1/2" long, mucronate Osteomeles schweriniae

Terminal leaflets 1" or more long, emarginate Sophora secundiflora

190 188 Leaflets broad ovate, long apiculate Dalbergia sissoo

Leaflets lanceolate to oval, obtuse to acute Sophora japonica

191 172 Trees; leaflets broadly oval to orbicular, to 1" or more wide Ceratonia siliqua

Trees or shrubs; leaflets obovate, ovate to linear, or if orbicular, then less than 1/4" wide 192

192 191 Leaves often of two types or dimorphic (once pinnate and twice pinnate leaves on the same tree); trees to 150' tall, with spreading branches; trunk with large, stout, simple or branched thorns Gleditsia triacanthos

Leaves not dimorphic; trees or shrubs to 40' tall 193

193 192 Trees; leaflets acuminate, often sickle shaped (falcate), distinctly inequilateral Pistacia chinensis

Trees or shrubs; leaflets not acuminate, not falcate, equilateral or not 194

194 193 Petiole with a gland between lowest leaflets; plants not armed 195

Petiole not with glands; plants sometimes armed 197

195 194 Leaflets linear, nearly terete, gray tomentose throughout Senna artemisioides

Leaflets oblong to ovate-lanceolate or obovate, green above, lighter green beneath, glabrous to pubescent, but not tomentose 196

196 195 Leaflets 3-6 pairs, obovate (to oblong), sparingly pubescent, long pubescent on midveins beneath, Senna splendida

Leaflets 2-3 pairs, oblong to ovate or lanceolate, glabrous Senna corymbosa

197 194 Plants with stipular spines, paired and slightly recurved; leaflets about 1/2" long Olneya tesota

Plants not with stipular spines; leaflets 1 or more inches long 197a

Leaflets about 1" long Cassia didymobotrya

198 140 Trunk with large white prickles at base Chorisia speciosa

Trunk not armed 199

199 198 Leaves opposite; leaflets dark green above, grayish tomentose beneath; old inflorescences persistent, flowers blue Vitex agnus-castus

Leaves alternate; leaflets never grayish tomentose beneath; inflorescence not persistent 200

200 199 Leaflets to 12" long, 5" wide, glabrous, margins entire Schefflera digitata

Leaflets to 6" long, to 2" wide, glabrous or pubescent, margins finely to coarsely dentate 201

201 200 Trees; leaflets pubescent, to 2" wide; margins finely dentate (denticulate) to subentire, petioles not blotched Casimiroa edulis

Shrubs; leaflets glabrous, to 1" side; margins coarsely dentate, petioles blotched Dizygotheca elegantissima

202 135 Leaves whorled or opposite (occasionally nodes with whorled, supopposite or even alternate leaves) 203

Leaves alternate (at least in upper portions of plant) 245

203 202 Leaves whorled, 3 leaves or more per node 204

Leaves opposite 207

204 203 Leaf blades broad ovate, 3" or more wide Catalpa bignonioides

Leaf blades linear to lanceolate, to 1" wide 205

205 204 Leaves elliptic to lanceolate to ovate, with a medicinal odor when bruised Myrtus communis

Leaves linear, not with a medicinal odor when bruised 206

206 205 Leaves rigid, upright on stem Nerium oleander

Leaves not noticeable thickened, drooping from stem Chilopsis linearis

207 203 Plants parasitic (but green), growing on branches of ash, willow or cottonwood trees Phoradendron flavescens

Plants not parasitic, not growing on branches of trees 208

208 207 Leaf blades mostly linear or narrowly lanceolate or oblanceolate, at least 3 times longer than wide 209

Leaf blades mostly not 3 times longer than wide 214

209 208 Plants low or trailing shrubs, strongly aromatic when bruised; leaf blades linear, margins revolute (nearly tubular) Rosmarinus officinalis

Plants upright, not strongly aromatic when bruised; leaf margins not strongly revolute 210

210 209 Leaves dark green above, lighter colored and tomentose or peltate scaled beneath 211

Leaves green on both surfaces, glabrous or nearly so 212

211 210 Trees; leaf blades to 3" long, thick, peltate scaled beneath; margins entire, slightly rolled under Olea europaea

Shrubs; leaf blades to 6" or more long, thin, tomentose beneath; margins serrate Buddleja davidii

212 210 Trees or shrubs (woody throughout except for current year's growth) to 5' or more feet tall 213

Suffrutescent herbs (woody only at base) to 3' tall Ruellia brittoniana

distinguish between, lavender, white and pink

213 212 Leaf blades mostly 4" or more long; leaves often opposite, whorled and alternate on same branch, drooping from stem. Chilopsis linearis

Leaf blades mostly less than 3" long; leaves all opposite, not drooping (dwarf plant with narrow leaves is cv. 'Nana') Punica granatum

214 208 Plants with milky sap, with dichotomously branching (bifurcate) thorns or thornless Carissa grandiflora

Plants not with milky sap, not with bifurcate thorns 215

215 214 At least some leaves with margins variously dentate, serrate, crenate or lobed, but not entire. 216

Leaf margins entire or undulate 225

216 215 Leaf margins deeply lobed (laciniate) to entire, not regularly serate, crenate or dentate. Syringa laciniata

Leaf margins regularly serrate, crenate or dentate, sometimes remotely so, but not lobed 217

217 216 Leaf blades very rough pubescent (strigose-scabrous) 218

Leaf blades not strigose-scabrous. 219

218 217 Leaf blades mostly 2-3 inches long; plants upright; older stems sometimes with prickles Lantana camara

Leaf blades mostly 1" long; plants trailing; stems not armed Lantana montevidensis

 distinguish between purple, white and monrovia multicolored form

219 217 Herbage stellate pubescent, at least when young, sometimes sparingly so 220

Herbage not stellate pubescent 221

220 219 Leaves acuminate, cuneate; margins coarsely crenate-serrate, tips of serrations not directed forward; petioles long, not deeply channelled above Callicarpa bodinieri var. giraldii

Leaves obtuse to acute, rounded to broadly cuneate; margins finely crenate-serrate, tips of serrations directed forward; petioles short, deeply channelled above Viburnum suspensum

221 219 Leaves foetid, broadly feltoid-ovate, truncate; margins coarsely dentate; petioles 1/2 to as long as blade Clerodendrum bungei

Leaves not foetid, not broadly deltoid-ovate, cuneate or rounded at base; margins finely serrate to crenate; petioles less than 1/3 length of blade 222

222 221 Branchlets bearing stipular ridges between opposing leaves; leaves obtuse to acute to acuminate, sometimes fleshyp; serrations not bristle-tipped 223

Branchlets not bearing stipular ridges; leaves obtuse, fleshy; serrations minutely rolled under or thickened, minutely bristle-tipped

cv. 'Albo marginata' has leaves with green centers and irregular white margins 'Viridi-variegatus has leaves with cream centers and irregular green margins, leaves less than 1" long in cv. 'Microphylla' Euonymus japonica

223 222 Branchlets glabrous; leaves thick, fleshy, mostly about 2" or more long 224

Branchlets pubescent; leaves thin, not fleshy, mostly about 1" long Abelia x grandiflora

224 223 Leaves obtuse; margins with a few remote teeth (sometimes entire); buds obtuse Viburnum japonicum

Leaves acute to acuminate; margins with many rather close-set teeth; buds acute Osmanthus fragrans

225 215 Shrubs or small trees, succulent; branches brittle; leaves glabrous, very fleshy, obovate to 1" long Portulacaria afra

Shrubs or small trees, not succulent; branches not brittle; leaves glabrous or pubescent, not very fleshy, shapes and sizes various 226

226 225 Leaves with a strong medicinal odor when bruised 227

Leaves not with a strong medicinal odor when bruised 228

227 226 Leaves ovate to elliptic, longer than wide, bases not overlapping about stem (type with leaves partially folded, crowded on stem, lower ones deflexed is cv. 'Boetica' ; dwarf form with small, flat leaves is cv. 'Compacta'  Myrtus communis

Leaves very broadly ovate, often wider or as wide as long, bases overlapping about the stem (mature leaf form much longer, hence plants are pruned back to maintain juvenile leaf form) Eucalyptus pulverulanta

228 226 Branchlets and leaves (at least on midveins beneath) pubescent 229

Leaves glabrous 238

229 228 Midveins appearing as white stripes on green surfaces beneath; leaf blades to 1" long 230

Midveins not appearing as white stripes on green surfaces beneath; leaf blades often more than 1" long 231

230 229 Leaves obovate, obtuse or emarginate Buxus microphylla

Leaves ovate to elliptic, not obovate, acute Buxus sempervirens

231 229 Lower leaf surfaces pubescent throughout (sometimes sparingly so) 232

Lower leaf surfaces pubescent only along veins (and sometimes margins) 237

232 231 Leaves felty beneath with dense white tomentum 233

Leaves not felty beneath 234

233 232 Stem squarish and minutely ridged longitudinally along angles; stipular ridge between opposing leaves present; lateral veins sharply directed forward forming about 30 degree angles with midvein Teucrium fruticans

Stem terete, not ridged longitudinally; no stipular ridge; lateral veins less sharply directed forward, forming 34-60 degree angles with midvein Feijoa sellowiana

234 232 Leaves sessile or very short-petioled Simmondsia chinensis

Leaves distinctly petioled 235

235 234 Leaves distinctly oblanceolate, short apiculate Duranta stenostachya

Leaves ovate to elliptic 235a

Leaves obtuse to acute; flowers red, orange or white 235b

Petioles short, less than one-fourth length of leaf; flowers red or orange, in open clusters, bracts in conspicuous or absent 236

236 235b Leaves broadly ovate; flowers red, in elongate unbranched clusters Justicia californica

Leaves elliptic; flowers orange, in short branching clusters Jacobinia hybr.

237 231 Leaves long-petioles; lateral veins with tufts of hairs in axils; pubescence often partly stellate Viburnum tinus

Leaves short-petioled or sessile; lateral veins sometimes pubescent, not stellate Lagerstroemia indica

238 228 Branches ending in two lateral buds, terminal bud aborting Syringa x persica

Branches ending in one functional terminal bud 239

239 238 Leaves narrowly elliptic to often oblanceolate, not with obvious waxy coating; branchlets margined or winged, sometimes spinescent Punica granatum

Leaves broadly elliptic to ovate, not oblanceolate, usually with obvioius waxy coating; branchlets not margined, not winged, not spinescent 240

240 239 Branchlets obviously pubescent; some leaves usually alternate, deflexed Polygala dalmaisiana

Branchlets glabrous or nearly so; leaves opposite 241

241 240 Lenticels present on branchlets; stipules not large and sheathing; veins not impressed (sunken) above 242

Lenticels not present on branchlets; stipules large, sheathing; veins impressed (sunken) above Gardenia jasminoides

242 241 Bud scales stellate pubescent Viburnum japonicum

Bud scales glabrous or with very short simple hairs 243

243 242 Leaf blades elliptic, ovate or oblong, 1 to 2 1/2" long, acute, cuneate (leaf margins variegated with yellow in cv. 'Aureum') Ligustrum ovalifolium

Leaf blades rounded ovate to ovate-lanceolate, 2-6" long, obtuse, acute, or acuminate, rounded or tapering at base 244

244 243 Leaf blades 4-6" long, long acuminate; shrubs or shall trees to 30' tall Ligustrum lucidum

Leaf blades 2-4" long, short acuminate to obtuse; shrubs to 10' tall Ligustrum japonicum

245 202 Stems armed with spines, thorns or thorn-like branches 246

Stems not armed 265

246 245 Petiole winged or margined, jointed at base of blade; Citrus (best distinguished by fruits; many hybrids known; thorniess and leaf margins variable) 247

Petiole neither winged or margined, not jointed at base of blade 253

247 246 Fruit ovoid, sometimes nippled at apex 248

Fruit spherical or apically depressed, not nippled 250

248 247 Petiole narrowly winged; fruit sometimes nippled, greenish yellow to orange when ripe 249

Petiole margined; fruit nippled, yellow when ripe Citrus lemon

249 248 Small trees or shrubs, usually thornless; fruit sometimes nippled, flesh greenish Citrus aurantiifolia

Small trees, often thorny; fruit not nippled, flesh orange-yellow Fortunella margarita

250 247 Fruit 3' or more in diameter, skin tight; fruit segments inside not readily separable 251

Fruit 2-3" in diameter, skin loose; fruit segments inside readily separable Citrus reticulata

251 250 Skin of fruit warty, orange; fruit sour Citrus aurantium

Skin of fruit smooth, yellow or orange; fruit sweet to sour 252

252 251 Fruits 4" or more in diameter, yellow, sour Citrus paradisi

Fruits about 3" in diameter, orange, sweet Citrus sinensis

253 246 Shrubs; leaves and stems bearing peltate scales; blades silvery below, speckled brown

Trees or shrubs; leaves and stem not bearing peltate scales 254

254 253 Vein pattern palmate; leaves arranged on slender branches giving the appearance of being pinnately compound

Vein pattern pinnate or palmate; leaves not appearing as being compound 255

255 254 Stems bearing spines (modified leaf structures) 256

Stems bearing thorns (modified stems) 259

256 255 Spines are modified bracts along main axes; leaves (actually modified stems called cladodes) fascicled 257

Spines are modified persistent petioles (with buds at base, in axils) 258

257 256 Cladodes about 1" long, straight or nearly so, margins not noticeable crisped

Cladodes bout 2-3" long, often sickle-shaped (falcate), margins often noticeable crisped

258 256 Plant branching near its base into many wand-like stems bearing greenish stripes or patches Fouquieria splendens

Plant with large whitish inverted carrot-shaped trunk, bearing lateral branches throughout; not with greenish stripes or patches Idria columnaris

259 255 Trees; leaves ovate, long acuminate or apiculate 260

Shrubs, sometimes vine-like; leaves various 261

260 259 Trees with milky sap; leaf margins entire or ciliate Maclura pomifera

Trees not with milky sap; leaf margins serrate Pyrus kawakami

261 259 Leaf blades obovate to oblanceolate, widest above the middle 262

Leaf blades ovate to lanceolate, widest below the middle 263

262 261 Leaves fleshy, obtuse, not emarginate, not stipulate; margins entire Lycium exsertum

Leaves not fleshy, usually emarginate, stipulate; margins irregularly serrate to entire Pyracantha fortuneana

263 261 Shrubs with vine-like branches; leaves entire, apiculate Bougainvillea spectabilis

Shrubs not with vine-like branches; leaves serrate, crenate or sometimes entire, not apiculate 264

264 263 Leaves 2" or more long; stipules (when present) large, broad and leaf-like Chaenomeles japonica

Leaves mostly to 1" long; exstipulate Condalia lycioides

265 245 Leaf margins lobed, serrate, dentate or crenate, but neither entire nor undulate 266

Leaf margins entire or undulate (wavy) 328

266 265 Leaf margins distinctly lobed (at least in some leaves) 267

Leaf margins serrate, dentate or crenate, not distinctly lobed 290

267 266 Leaf margin two-lobed (bilobed) 268

Leaf margin not bilobed 270

268 267 Shrubs; leaves small, viscid; lobes pointed, midvein prolonged slightly between them Larrea divaricata

Trees; leaves larger, not viscid; lobes rounded, not evident midvein 269

269 268 Vein pattern dichotomous; internodes of some branches markedly shortened Ginkgo biloba

 
Vein pattern palmate; internodes not markedly differentiated (flowers purple; white flowered variety is candida) Bauhinia variegata

270 267 Primary lobes and vein pattern of leaf pinnate 271

Primary lobes and vein pattern of leaf palmate 278

271 270 Shrubs; semi-succulent; leaf blades large to 3' long, deeply secondarily lobed Philodendron selloum

Trees or shrubs; sometimes semi-succulent; leaf blades less than 2' long 272

272 271 Trees to 150' tall; leaf blades 10" long or more long, with secondary lobes entire or again lobed, silky beneath; margins revolute Grevillea robusta

Trees or shrubs to 60' tall; leaf blades usually less than 8" long, not with secondary lobes, not silky beneath; margins not revolute 273

273 272 Trees or shrubs to 60' tall, with slender drooping branchlets 274

Small trees or shrubs to 15' tall, with upright branches or unbranched 276

274 273 Leaf blades rhombic (diamond-shaped), bearing a few lobes; branches drooping Pittosporum rhombifolium

Leaf blades not rhombic; branches sometimes drooping 275

275 274 Trees; leaves ovate with long acuminate tips; unlobed or with 1-5 shallow lobes Brachychiton populneum  

Shrubs; at least some leaf margins deeply 3-7 lobed Syringa laciniata

276 273 Plants semi-succulent; stems wand-like with milky sap; leaves not rigid Euphorbia pulcherrima

Plants not succulent; stems neither wand-like nor with milky sap 277

277 276 At least some leaves lyrate-pinnatifid; sprawling shrubs; bark peeling Oenothera speciosa var. childsii

Leaves rectangular, bearing a few lobes with stout spines, not lyrate-pinnatifid; upright shrubs; bark not peeling (margins little lobed to entire in cv. 'Burfordii') Ilex cornuta

278 270 Primary lobes (and secondary lobes if present) with entire, lobed or undulate margins 279

Primary lobes (and secondary lobes if present) with crenate, serrate or dentate margins 283

279 278 Suffrutescent herbs, vines or low shrubs to 12' or sometimes more if vine-like 279a

Trees to 60'; leaves various 280

Leaves not leathery, more than 5-lobed Tetrapanax papyrifera

280 279 Large trees with bark peeling in large flakes; petiole covering the bud Platanus wrightii

Trees, not with bark peeling in large flakes; petiole not covering the bud 281

281 280 Trees with drooping branches; leaves ovate with long acuminate tips and unlobed or with 1-5 lobes Brachychiton populneum

Trees, not with drooping branches; leaves ovate-orbicular with 3-5 digitate lobes, not long acuminate 282

282 281 Leaves glabrous (except for a few scattered stellate hairs on veins); lobes obtuse Brachychiton acerifolium

Leaves with stellate hairs, at least beneath; lobes acute Firmiana platanifolia

283 278 Leaves peltate Ricinus communis

Leaves not peltate 284

284 283 Large trees with bark peeling in large flakes; petiole covering the bud Platanus x acerifolia

Trees or shrubs, not with bark peeling in large flakes; petiole not covering the bud 285

285 284 Upper surfaces of leaf blades distinctly very scabrous 286

Upper surfaces pubescent or glabrous, but not distinctly very scabrous 287

286 285 Stipular ring scars present (sometimes incomplete rings); stems with abundant milky sap Ficus carica

Stipular ring scars not present; stems not with abundant milky sap Broussonetia papyrifera

287 285 Trees to 50'; leaf margins unlobed or regularly to irregularly lobed (common form is cv. Mapleleaf; small leaved weeping form cv. Pendula

Shrubs to 15' tall; leaf margins usually lobed 288

288 287 Leaves glabrous; primary lobes 5-9 Fatsia japonica

Leaves with at least a few stellate hairs (sometimes simple hairs also); primary lobes usually 3 289

289 288 Leaves tomentose, margins shallowly 3-lobed, bases cordate to truncate; petioles about as long as blade Malvaviscus arboreus

Leaves nearly glabrous, margins shallowly to deeply 3-lobed, these often secondarily lobed, bases cuneate; petioles less than 1/2 length of blade Hibiscus syriacus

290 266 Prostrate subshrubs to about 1' tall; leaves oblanceolate to obovate 291

Trees or shrubs; leaves various 292

291 290 Leaves and stems bumpy glandular, blades narrowly lanceolate Myoporum parvifolium

Leaves and stems not bumpy glandular, blades broadly oblanceolatre to obovate, scurfy Baccharis pilularis

292 290 Stems with abundant milky sap 293

Stems not with abundant milky sap 294

293 292 Stipular ring scars present; leaves ovate-orbicular, margins coarsely dentate Ficus roxburgii

Stipular ring scars not present; leaves elliptic to ovate; margins irregularly few-toothed Euphorbia pulcherrima

294 292 Leaves (actually phyllodes) triangular to 1" long, midvein strongly curved with mucro at apex forming one angle of triangle, one lateral glandular tooth forming another angle Acacia cultiformis

Leaves not triangular as described above, lengths various 295

295 294 Petioles winged or margined, jointed at base of blade; blade glandular dotted, irregularly serrate or crenate to entire; Citrus(best distinguished by fruits, many hybrids known; see Key Number 247ff for additional species) 296

Petioles not winged or margined, not jointed at base of blade; blade not glandular dotted; regularly to irregularly serrate, crenate or dentate 297

296 295 Trees to 2-' tall; fruit spherical, smooth-skinned, orange, to 3" long, with many compartments (locules) inside Citrus sinensis

Shrubs or small trees to 12' tall; fruit ovoid, 1 to 1 1/2" long with 4-5 locules Fortunella margarita

297 295 Trees; leaf bases usually distinctly inequilateral 298

Trees or shrubs; leaf bases equilateral or nearly so 300

298 297 Leaf margins doubly serrate Ulmus americana

Leaf margins simply serrate 299

299 298 Leaves ovate-oblong, long acuminate; trunks gray, smooth or with warty protuberances Celtis occidentalis

Leaves elliptic-ovate, acute; trunks dark, furrowed at maturity Ulmus parvifolia

300 297 Leaves rhombic (diamone-shaped); dentations coarse, irregular 301

Leaves not rhombic; dentations or serrations various 302

301 300 Leaves and branchlets covered with mealy silvery gray scales Atriplex lentiformis ssp. breweri

Leaves and branchlets glabrous, not with mealy scales Pittosporum rhombifolium

302 300 Leaf blades broadest at or below the middle, lanceolate, ovate, deltoid, ovate-orbicular, oval or elliptic (often some leaves broadest above the middle, rarely consistently so) 303

Leaf blades prevailingly broadest above the middle-oblanceolate or obovate 322

303 302 Serrations or dentations spinescent 304

Serrations or dentations or crenations not spinescent, but sometimes with very minute bristles 309

304 303 Large trees; leaves tomentose (at least beneath), pubescence stellate in part 305

Shrubs or small trees; glabrous to tomentose, but not stellate 306

305 304 Bark much corky, deeply furrowed at maturity leaf margin regularly dentate Quercus suber

Bark not corky, smooth at maturity; leaf margin with few dentations to nearly entire Quercus ilex

306 304 Leaf margins regularly serrate or dentate; leaves and branchlets bearing some pubescence; leaves elongate 307

Leaf margins irregularly serrate to entire; leaves and branchlets glabrous; leaf shapes various 308

307 306 Leaves whitish tomentose beneath sometimes becoming glabrate, distinctly cuneate at base

Leaves tan or brown pubescent beneath sometimes becoming glabrate, bases rounded to broadly cuneate

308 306 Shrubs; dentations bearing stout spine tips; leaves very thick, rigid

Small trees; dentations spinescent, but not bearing stout spine tips; leaves thick, a little flexible

309 303 Petioles bearing glands at base of blade 301

Petioles not bearing glands 311

310 309 Leaves broadly ovate, apiculate

Leaves narrowly lanceolate, acuminate

311 309 Leaves obviously pubescent, well distributed 312

Leaves glabrous or very nearly so 314

312 311 Trees or shrubs; leaf blades palmately veined 313

Trees; leaf blades pinnately veined 312a , not broad ovate, to 3" long, finely serrate

Leaf margins coarsely dentate or crenate Populus alba

313 312 Trees; leaves not stellate pubescent 313a

Shrubs; leaves sparsely stellate pubescent; petiole not channelled above

Leaves not tomentose beneath (common form is  cv. 'Maple Leaf'; small leaved, weeping form is cv. 'Pendula' Morus Alba

314 311 Trees; leaves narrowly lanceolate to linear 314a

Trees or shrubs; leaves broadly ovate to elliptic, not narrowly lanceolate or linear 316

Leaves and branches not twisted or contorted 315

315 314a Branches distinctly pendulous

Branches not distinctly pendulous

316 314 Leaves broadly deltoid-ovate; coarsely crenate-dentate, tips often incurved; petiole flattened laterally

Leaves not broadly deltoid-ovate; petiole not flattened laterally 317

317 316 Leaf blades obtuse, about 1" long, margins serrate-crenate, crenations tipped with minute bristles

Leaf blades acute to acuminate; mostly 1 1/2" or more long; serrations sometimes minutely bristled 318

318 317 Leaves purple

Leaves green 319

319 318 Trees; leaf tips apiculate, abruptly narrowed into a prominent point 320

Shrubs; leaf tips acuminate, not abruptly narrowed to a point 321

320 319 Leaves deciduous; petioles naked

Leaves evergreen; petioles usually bearing a few serrations extending down from blade

321 319 Marginal serrations usually bearing minute yellow callosites, not minute bristles

Marginal serrations bearing minute bristles, not callosities

322 302 Shrubs; leaves definitely obovate; serrations, crenations or dentations mostly restricted to upper half of blade 323

Trees or shrubs; leaves oblanceolate; serrations, crenations or dentations to well below the middle of the leaf blade 325

323 322 Branches pendulous; leaf blades thin, less than 1" long

Branches not pendulous; leaf blades thick, lengths various 324

324 323 Leaf blades less than 1" long, glandular dotted

Leaf blades mostly 1 1/2" or more long, not glandular dotted (R. indica Lindl. and intermediate hybrid, R. x delacourii, have sharper dentations and pink flowers, not white as in R. umbellate)

325 322 Leaf blades tawny to rusty tomentose beneath, 5-10 inches long

Leaf blades glabrous or glabrate, not tomentose, 2-6" long 326

326 325 Leaf apex mucronate; younger branchlets pubescent or glabrous, not stipitate glands, stipulate 327

Leaf apex not mucronate; younger branchlets often hirsute or with stipitate glands; exstipulate

327 326 Leaf blades elliptic-oblanceolate, usually reddish beneath when immature; stamens 10, persisting on fruit

Leaf blades oblong-oblanceolate, greenish beneath when immature; stamens 20, persisting on fruit (serrations spinescent in cv. Aculeata)

328 265 Petioles succulent, ensheathing stem; leaf blades 1-5 feet or more long; stem unbranched 329

Petioles sometimes succulent but not ensheathing stem; leaf blades usually less than 1' long; stems branching 332

329 328 Leaves arranged in two opposing rows along stem (two-ranked) 330

Leaves more than two-ranked 331

330 329 Leaf blades 2-5' long; false trunks 3' or more tall, of 3" or more in diameter Strelitzia nicolai

Leaf blades 12-18" long; trunkless or false trunk to 1' tall, of 1 1/2" or less in diameter Strelitzia reginae

331 329 Leaf blades 3-5 feet or more long, shredding in wind; plants appearing as small trees Musa nana

Leaf blades to 2' long, not shredding in wind; plants suffrutescent herbs, not appearing as small trees Canna generalis

332 328 Leaf blades leathery, with a medicinal or spice odor 333

Leaf blades sometimes leathery, not with a medicinal or spice odor 345

333 332 Leaf with spice odor (bay leaves), blades elliptic, 2-4" long Laurus nobilis

Leaf with medicinal odor; blades various 334

334 333 Clusters of sessile woody fruits persisting along stems 335

No Clusters of sessile woody fruits persisting along stems 339

335 334 Leaves about 1" or less long

Leaves about 1 1/2" or more long 337

336 335 Leaves tp 1/2" long, narrow, acuminate, inflorescence cylindric, 1-2" long Melaleuca pubescens

Leaves to 1" long, obovate, obtuse, mucronate; inflorescence a globose head about 1" long Melaleuca nesophyla

337 335 Small trees with pendulous branches Callistemon viminalis

Small trees or shrubs, not with pendulous branches 338

338 337 Leaves to 1/4" wide; new growth pubescent Callistemon rigidus

Leaves to 1/2" wide; new growth densely downy pubescent Callistemon citrinus

339 334 Trees; leaves petiolate, not crowded 340

Small trees or shrubs; leaves sessile or very short petiolate, usually crowded  339a

Leaves partially folded, crowded on stem, lower leaves deflexed or dwarf form with small flat leaves 339b

339b Dwarf form of 339a

Leaves partially folded, crowded on stem, lower leaves deflexed

340 339 Leaf blades narrowly lanceolate, mostly at least 4 times longer than wide, mostly broadest near the base and tapering to a long point 341

Leaf blades less than 3 times longer than wide 344

341 340 Bark of main branches smooth, peeling in plates 342

Bark of main branches rough, not peeling in thin plates 343

342 341 Bark and branchlets gray to brown; flowers whitish Eucalyptus camaldulensis

Bark whitish, branchlets bright reddish; flowers whitish to reddish Eucalyptus leucoxylon

343 341 Trees mostly to 20' tall; branchlets yellowish, little pendulous; fruits about 1/4" in diameter Eucalyptus torquata

Trees to 80' tall; branchlets reddish, pendulous; fruits about 1/8" in diameter Eucalyptus sideroxylon

344 340 Leaf blades nearly as wide to wider than long in juvenile leaf forms, more elongate in mature forms, silver gray, glaucous Eucalyptus polyanthemos

Leaf blades elliptic-ovate, reddish tinged when young turning greenish blue Eucalyptus rudis

345 332 Leaf blades linear, narrowly lanceolate or narrowly oblanceolate, mostly 4 or more times longer than wide 346

Leaf blades mostly less than 3 times longer than wide 358

346 345 Shrubs; stems green, wand-like or broom-like, longitudinally striate or winged 347

Trees or shrubs; stems not wand-like, not broom-like 348

347 346 Stems wand-like, finely striate; leaves elliptic, pubescent, not viscid-glandular Spartium junceum

Stems ascending, broom-like, winged; leaves linear, glabrous, viscid-glandular Baccharis sarothroides

348 346 Plants with milky sap Thevetia peruviana

Plants not with milky sap 349

349 348 Trees; leaf blades mostly to 1/2" long, linear, arranged on deciduous branchlets as to appear pinnately compound leaves Taxodium mucronatum

Trees or shrubs; leaf blades about 1" or more long, not arranged on branchlets as to appear as pinnately compound leaves 350