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A field key to the genera of the wild aPxd cultivated hardy trees of the northeastem U. S. and Canada, by
Mary Franklin Barrett.
Bloomfield, N. J. 1931
Utaia.
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A FIKLD KKY
TO
The Genera of the Wild and Cultivated
Hardy Trees of the Northeastern
United States and Canada
BY
MARY FRANKLIN BARRETT
formerly of the State Normal School and the State Teachers' College, Montclair, New Jersey
64 PARK AVENUE BLOOMFIELD, NEW JERSEY
1931
Price, Thirty-five Cents
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A FIELD KEY
TO
The Genera of the Wild and Cultivated
Hardy Trees of the Northeastern
United States and Canada
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BY
MARY FRANKLIN BARRETT
formerly of the State Normal School and the State Teachers' College, Montclair, New Jersey
64 PARK AVENUE BLOOMFIELD, NEW JERSEY
1931
Copyright, 1931, by MARY F. BARRETT
Printed by
The Independent Press
Bloomfield, N. J.
CONTENTS
Introduction : 4
References 6
Key _ 7
Plate of Leaf and Twig Characters 28
Explanation of Terms as used here 29
Index to Scientific and English Names 37
INTRODUCTION
This KEY is a mechanical device for finding the names of trees by means of characteristics possessed by their leaves, stems and winter- buds. It is mechanical in the same sense as is a crossword puzzle : the leaves are grouped according to similarities in their external structure, and not with regard to their family relationships.
It is called a FIELD KEY because it is intended to be used where trees are growing, since some of the characteristic organs are too large to be carried away. Because leaves are of primary importance for iden- tification the KEY can be used only when trees are in full leaf. The characters which have to do with stems are always on hand, summer and winter. New winter-buds are fully developed by late summer or autumn ; but sometimes may be found at other times, unopened, on old twigs.
A tree is a woody plant, 12 feet or more in height, which has one main trunk rising an appreciable distance (a foot or so) above the ground before it branches. Thus it is differentiated from a shrub, which has more than one trunk, or perhaps has none at all above ground. However some shrubs have tree relatives, and these have been included, although their descriptions would not apply necessarily to the shrubs.
The range of the trees included runs from northern Canada to a line about as far south as central Virginia, and west to the Mississippi River. Many of the trees will extend farther south and west. Some genera will grow over most of the range, while others are restricted to a much smaller territory. Only those hardy in at least the southern part of the area have been listed.
Both wild and cultivated trees have been classified. The cultivated ones, many of which have been imported from other countries, often escape into the fields and woods by means of their seeds ; and the native forms frequently are cultivated. Thus both kinds may be encountered in the same sort of place.
The KEY is intended to identify genera and not species : for exam- ple, the pines and the maples arc mentioned, but not the white pine or the sugar maple. Apparent exceptions are due to the presence in the genus of only one species, which may then be named ; to the variation of a species from the rest of its relatives in the genus ; or to the fact that the stated name is applied to all the species in the genus. Occa- sionally large genera, such as PRUNUS, have been subdivided. The same genus may appear several times if its characteristics are so in- definite that a choice in the KEY is difficult, or if its species differ much as to leaves or twigs. In naming the genus the common names are put first, and then the scientific name in a parenthesis. No varieties of species, or hybrids, or doubtful species have been considered in charac- terizing the genera. The KEY includes most of the species mentioned
4
by Rehder in his "Manual of cultivated trees and shrubs" as belonging to the eastern part of his "Zones" I-VI and to the eastern and northern parts of Zone VII. With a few exceptions the names are as given by Rehder. There is listed only one genus poisonous to the touch, RHUS, the sumac, whose toxic species have pinnately compound leaves with entire margins and 7-15 leaflets. Other species of RHUS are harmless.
When using the KEY start with section 1 ; read all the descriptions, choose the one which fits the tree being studied, and then look up the section indicated by the number opposite to the description. Proceed in this way after the manner of a treasure-hunt until a name is reached. As a rule the most striking character is placed first in the description. If no characterization fits, take the best, or try all. Base the decision on a comparison of several leaves, twigs, etc. ; not on one alone. Only actual statements in the KEY should be considered. Frequently the first part of a section is more detailed than those which follow it, either because fewer trees are governed by it, or because it is describing a sin- gle genus. Absence of these details in the other part or parts does not imply their opposite ; it merely means that no general rule can be made as yet. Whenever a term is unfamiliar or doubtful it should be looked up in the EXPLANATION OF TERMS, as even common expressions may here be used in a slightly different sense from that usually under- stood. The EXPLANATION also gives suggestions for methods of ex- amination. The species may be identified by using more detailed books, such as those listed as references.
The author will greatly appreciate the reporting of any mistakes or difficulties.
Grateful acknowledgement is made of the assistance of Mr. Percy Wilson, Assistant Curator of the New York Botanical Garden, and of the advice of Dr. Otis W. Caldwell of Columbia University. The de- scriptions in Rehder's MANUAL and Trelease's plates were invaluable in preparing the KEY.
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REFERENCES
Bailey, L. H. The cultivated evergreens. Newr York. The Macmillan Co. 1923. Keys and descriptions by Alfred Rehder. Illustrated.
Bailey, L. H. ed. Standard cyclopedia of horticulture. Newr York. The Macmillan Co. 1914-1917. Keys and short descriptions, with a few illustrations. Cultivated trees, both native and imported, are in- cluded.
Bailey, L. H., and Bailey, E. Z. Hortus. New York. The Macmillan Co. 1930. Keys and short descriptions of cultivated trees and other plants. An abridged encyclopedia, including culture.
Blakeslee, A. F., and Jarvis, C. D. Trees in winter. New York. The Macmillan Co. 1913. Illustrations of native trees and descriptions.
Illick, J. S. Tree habits, how to know the hardwoods. Washington. 1924. Illustrations, descriptions and keys to native deciduous trees. Good diagrams and plates, particularly of bark.
Muenscher, W. C. Keys to woody plants. Ithaca, N. Y. 1922. Sum- mer and winter keys to genera and species likely to be found in New York State. A small pamphlet.
Rehder, Alfred. Manual of cultivated trees and shrubs hardy in North America. New York. The Macmillan Co. 1927. Very complete descriptions and keys to genera and species of native and imported trees. The main reference for this KEY.
Rogers, J. E. The tree book. Doubleday, Page & Co. 1914. De- scriptions and illustrations of wild and cultivated forms written in an entertaining style with many additional facts of interest.
Trelease, W. Plant materials of decorative gardening. Urbana, 111. 1926. Genera and species keys, and descriptions of native and im- ported trees. In brief form. Very complete.
Trelease, W. Winter botany. Urbana, 111. 1925. Keys to genera and species, short descriptions, and plates of twigs of deciduous trees and shrubs. Has been very valuable for this KEY.
Wiegand, K. M., and Foxworthy, F. W. A key to the genera of woody plants in winter. Ithaca, N. Y. 1908. A pamphlet in key form for field use. Includes cultivated genera.
Local material on trees published by State Experiment Stations, State Universities, or Departments of Forestry.
KEY
1 Leaves evergreen _ 2
1 Leaves deciduous (including evergreen-like forms) 30
2 Leaves usually more than 1 cm. wide, resembling deciduous
leaves in shape and veining 3
2 Leaves 1 cm. wide or less, not like deciduous leaves 12
BROAD-LEAVED EVERGREENS
3 Leaves opposite .„ 4
3 Leaves spirally arranged or crowded near tip of twig — 5
4 Leaves entire, blunt or notched at tip, 1-3 cm. long..BOX(BUXUS)
4 Leaves usually spiny-toothed, spiny-pointed, 2-6 cm. long
FRAGRANT OLIVE (OSMANTHUS)
5 Stipule-scars encircling twig at each node ; buds one-scaled
BULL BAY (MAGNOLIA)
5 Encircling scars only at beginning of each year's growth ; buds
showing more than one scale 6
6 Leaves spiny-toothed, at least part-way HOLLY (ILEX) -
6 Leaves toothed, although sometimes faintly, never spiny 7
6 Leaves entire 9
7 Only one bundle-scar in the leaf-scar HOLLY (ILEX)
7 Three bundle-scars in the leaf-scar 8
8 Leaves resinous-dotted ; visible bud-scales about 2-4
WAX-MYRTLE (MYRICA)
8 Leaves not resinous-dotted ; visible bud-scales more than 4
PORTUGAL LAUREL, CHERRY LAUREL (PRUNUS)
9 Largest buds showing 6 or more scales ; leaves 8-20 cm. long
(RHODODENDRON) 9 Buds scaleless or showing not more than 6 scales 10
10 Bundle-scars 3, forming a triangle WAX-MYRTLE (MYRICA)
10 Bundle-scar one, compound, like a horizontal line H
11 Leaves sharp-pointed, usually crowded at tip of twig
MOUNTAIN LAUREL (KALMIA) ' 11 Leaves blunt-tipped, not usually crowded....RED BAY (PERSEA)
7
NARROW-LEAVED EVERGREENS
12 Conspicuous leaves needle-like; scale-like leaves sometimes
also present 13
12 Leaves like scales, spikes or wedges ; sometimes more than one
type on a tree • 22
13 Needles in spirally arranged clusters of 2-8 along twig
PINE (PINUS) "^
13 Needles in whorls of 3 at nodes on twig.JUNIPER (JUNIPERUS) •"
13 Needles in a whorl of 15-30 at tip of twig
UMBRELLA PINE (SCIADOPITYS)
13 Needles in clusters on spurs and scattered singly on leading
shoots CEDAR (CEDRUS)
13 Needles always scattered, never in clusters or whorls 14
14 Leaves curved, with a keel or ridge on each surface; under
surface not paler than upper
JAPANESE CEDAR (CRYPTOMERIA) [^
14 Leaves not as just described 15
15 Twigs bearing cushions or ridges from which leaves grow 16
15 Twigs without cushions and almost smooth 21
16 Leaf-arrangement obviously spiral; each leaf growing from a
peg of the leaf-cushion, usually sharp-tipped or 4-sided or
both SPRUCE (PICEA) '^
16 Leaf arrangement usually apparently 2-ranked or forming a
V-shaped trough; leaves never on pegs but sometimes petioled *■'
17 Leaves usually blunt-tipped or notched, sharp-tipped only when
finely toothed or spirally arranged; short-petioled
HEMLOCK (TSUGA) ;.
17 Leaves always sharp-tipped, but not with above combination.... 18
18 Leaves finely toothed, not petioled, bearing white bands on
under surface CHINA-FIR (CUNNINGHAMIA)
18 Leaves entire, sometimes petioled 19
19 Twigs not opposite to one another; leaves sharp — ^but not
spiny-tipped, paler on under than on upper surface but
without light bands YEW (TAXUS)
19 Twigs nearly opposite to each other; leaves sometimes spiny- tipped, always with light bands on under surface 20
8
20 Leaves with a prominent mid-rib on upper surface, light bands on under surface wider than green bands
PLUM-YEW (CEPHALOTAXUS)
20 Leaves without prominent mid-rib, light bands narrower than
green bands (TORREYA)
21 Leaf-scars oval, raised at lower end; leaf sometimes with an indistinct petiole; buds never resinous
DOUGLAS FIR (PSEUSOTSUGA)
21 Leaf-scars round, not raised; leaf with a narrow or twisted
base but no petiole ; buds sometimes resinous FIR (ABIES)
22 Leaves spirally arranged 23
22 Leaves in 3 or 4 ranks — • 24
23 Leaves spike-like, flaring out, but also curved in at tip towards
twig JAPANESE CEDAR (CRYPTOMERIA) -
23 Leaves scale-like, flaring only slightly if at all
CALIFORNIA BIG-TREE (SEQUOIA)
24 Leaves in 3 or 4 ranks ; twigs roundish or squarish 25
24 Leaves in 4 ranks ; twigs almost flat 27
25 Leaves without whitish bands on either surface, leaf-margin
usually delicately fringed CYPRESS (CUPRESSUS)
25 Leaves usually with white bands on one surface, entire 26
26 Leaves 3- or 4-ranked, scale-like or spike-like or both, often with one or more white bands on upper surface
JUNIPER, RED CEDAR (JUNIPERUS) \/
26 Leaves 4-ranked, always scale-like in mature trees, without white bands on upper surface, sometimes with white marks on under surface WHITE CEDAR. FALSE CYPRESS (CHAMAECYPARIS) ^
27 Leaves scale-like, decurrent ; internodes longer than wide, twigs
green on both surfaces....INCENSE CEDAR (LIBOCEDRUS)
27 Leaves not very decurrent ; length and width of internodes
about equal, twigs often with white marks on under surface 28
9
28 Twigs 4-8 mm. wide ; leaves rather spiky, spreading on sides of
twig FALSE or HIBA ARBOR VITAE (THUJOPSIS)
28 Twigs 4 mm. wide or less ; side leaves scale-like and appressed, not spiky and spreading except on vigorous shoots, imma- ture plants and varieties. (The spiky form is called RETINISPORA or RETINOSPORA, but is not in a dif- ferent genus) 29
29 Twigs 3-4 mm. wide, sometimes standing up vertically ; side
scales nearly covering middle ones....ARBOR VITAE (THUJA)
29 Twigs less than 3.5 mm. wide ; side scales not much larger than middle ones unless leaves have white marks (not triangles) on under surfaces and one of the following conditions pres- ent : a tree trunk which peels in strips, or a gland on upper surface of leaf WHITE CEDAR, FALSE CYPRESS (CHAMAECYPARIS) l^
DECIDUOUS TREES
30 Leaves simple 31
30 Leaves compound 148
31 Leaves fan-shaped, almost parallel veined, sometimes cleft in the middle of the outer margin
MAIDENHAIR-TREE (GINKGO)
31 Leaves scale-like or very small, sometimes clasping twig
TAMARISK (TAMARIX)
31 Leaves needle-like - 32
31 Leaves normal foliage leaves, netted veined, not like above de- scriptions — 34
32 Leaves scattered along twig, never in clusters, appearing
2-ranked BALD CYPRESS (TAXODIUM) ^
32 Leaves in clusters on spurs, sometimes also scattered spirally.... 33
a Leaves Z-1 cm. long, at least 3 mm. wide, long-pointed
GOLDEN or CHINESE LARCH (PSEUDOLARIX)
IZ Leaves 1.5-4 cm. long, less than 3 mm. wide, blunt-tipped or short-pointed
LARCH, TAMARACK, HACKMATACK (LARIX)
lU
34 Leaves opposite or whorled, but all members of a pair or group sometimes not quite on the same level ; occasionally also single on spurs _ 35
34 Leaves spirally arranged, never 4-ranked, occasionally also clus- tered on spurs 51
SIMPLE OPPOSITE DECIDUOUS LEAVES
35 Leaves toothed, wavy-margined or lobed ; or both lobed and
toothed (or wavy) 36
35 Leaves entire, or angled with entire sides 42
36 Leaves palmately veined or palmately lobed or both 37
36 Leaves pinnately veined ; not lobed 38
o7 Leaves unlobed, wavy-toothed, somewhat heart-shaped, 5-10 cm. long; winter-buds appressed, end-bud absent, side-buds showing 1 or 2 scales
KATSURA-TREE (CERCIDIPHYLLUM)
37 Leaves lobed, or if unlobed then differing from the above de- scription of leaves and buds MAPLE (ACER)
38 Winter-buds superposed; teeth of leaves mostly above middle
SWAMP PRIVET (FORESTIERA)
38 Winter-buds usually solitary or side by side ; if superposed then
teeth of leaves not as just described 39
39 Leaves double-toothed, or wavy-toothed and bark white-striped
MAPLE (ACER)
39 Leaves single-toothed or wavy; bark not white-striped 40
40 Winter-buds showing one pair of scales
BLACK-HAW, NANNY- or SHEEP-BERRY (VIBURNUM)
40 Winter-buds showing more than 2 scales 41
41 Twig typically brown, often ending in a spine ; bundle-scars usually 3, or one forming a horizontal line through center of leaf-scar BUCKTHORN (RHAMNUS)
41 Twig typically green, not spiny; bundle-scar one, compound,
near top of leaf-scar SPINDLE-TREE (EVoNYMUS)
11
•
42 Leaves and twigs covered with silvery scales ; twigs often spiny
BUFFALO-BERRY (SHEPHERDIA) 42 Leaves and twigs sometimes hairy, but not silvery-scaly, not
spiny 43
43 Top side-veins of leaf curving to tip of leaf
DOGWOOD (CORNUS) \/ 43 Top side veins curving towards side margin or straight 44
44 Leaf-scars narrow, horizontal ; bundle-scars less than 6 45
44 Leaf-scars' height greater than width; bundle-scars 6 or more 49
45 Leaves more or less heart-shaped, at least at base
LILAC (SYRINGA)
45 Leaves oblong or oval 46
46 Leaves palmately veined MAPLE (ACER) )/
46 Leaves pinnately veined 47
47 Bundle-scars 3 or more MAPLE (ACER)
47 Bundle-scar one, a downward-curved line 48
48 Leaves 2 or 3 at a node ; leaf-scars almost or quite connected
by stipule-scars; winter-buds inconspicuous
BUTTON-BUSH (CEPHALANTHUS)
48 Not more than 2 leaves at a node; leaf-scars not connected;
winter-buds visible, superposed
FRINGE-TREE (CHIONANTHUS)
49 Only 2 leaves at a node, upper surface downy ; side-buds super-
posed EMPRESS-TREE (PAULOWNIA)
49 Leaves 2 or 3 at a node, upper surface nearly or quite hairless.. 50
50 Side-buds solitary; bundle-scars forming a complete oval
INDIAN BEAN (CATALPA) V
50 Side-buds superposed; bundle-scars forming a U
KUSAGI (CLERODENDRON)
SIMPLE SPIRAL SILVERY-SCALY LEAVES
51 Silvery scales covering twigs and at least under surface of
leaves "
51 Silvery scales not present on any part of tree 53
12
52 Silvery scales on both surfaces of leaves ; twig often ending in
a spine SEA-BUCKTHORN (HIPPOPHAE)
52 Silvery scales on under surface only; end-bud often present;
twigs often spiny OLEASTER (ELEAGNUS)
53 Tree bearing spines or prickles on twigs or branches 54
53 Twigs and branches unarmed, although leaves sometimes are
spiny 62
SPINY TWIGS. SIMPLE SPIRAL LEAVES
54 Leaves palmately 5-7-lobed ; prickles below leaf-scars
(ACANTHOPANAX) 54 Leaves palmately 3-veined, not lobed ; spines in place of stipules 55
54 Leaves pinnately veined, sometimes also lobed 56
55 Leaves 2-6 cm. long, petioles .1-.5 cm. long.JUJUBE (ZIZYPHUS)
55 Leaves 2-3.5 cm. long, petioles .4-L2 cm. long
CHRIST-THORN (PALIURUS)
56 Juice of young leaves milky ; leaf-margin entire
OSAGE ORANGE (MACLURA) 56 Juice of young leaves watery ; leaf-margin sometmes entire 57
57 Leaves usually both toothed and lobed 58
57 Leaves entire or toothed, but not lobed 59
58 Spines in leaf-axils ; visible winter-bud scales about 5-6, often
fleshy HAWTHORN (CRATAEGUS)
58 Spines made from spurs or ending side-twigs ; visible bud- scales about 4, not fleshy..CRABAPPLE (MALUS or PYRUS) l^
59 Leaves 2-5 cm. long, coarsely toothed, in 2 ranks, petioles 1-3
mm. long _ (HEMIPTELEA)
59 Leaves in more than 2 ranks, usually entire, wavy- or finely
toothed 60
60 End-bud not present ; stipule-scars present ; leaf-margin usual- ly distinctly toothed PLUM (PRUNUS) i
60 End-bud usually present ; stipule-scars not visible ; leaf-margin
usually entire or faintly wavy-toothed 61
13
61 Twigs hairy; leaves slightly hairy and dull green on upper sur- face, more hairy on under surface, 6-12 cm. long, faintly toothed or entire MEDLAR (MESPILUS)
61 Twigs and leaves not exactly as just described PEAR (PYRUS) ^
SIMPLE SPIRAL LEAVES, UNARMED TWIGS
62 Stipules or stipule-scars almost or quite encircling twig at base
of each petiole "^
62 Encircling scars only at beginning of each year's growth 66
63 Base of petiole cone-shaped, covering winter-bud
SYCAMORE (PLATANUS)
63 Winter-buds visible in leaf-axils 64
64 Outer end of leaf square or notched as if tip were cut oflF
TULIP TREE (LIRIODENDRON)
64 Outer end of leaf pointed or rounded 65
65 Leaves thin, sometimes toothed, winter-buds showing several
scales BEECH (FAGUS)
65 Leaves thick, entire, winter-buds showing one scale..(MAGNOLIA)
66 Juice of young leaves rubbery, making elastic cords when leaf
is broken; leaf-margin toothed (EUCOMMIA)
66 Juice of young leaves gummy; leaf-margin entire
CHITTAM-WOOD, AMERICAN SMOKE-TREE (COTINUS)
66 Juice of young leaves milky ; leaves varying in shape 67
66 Juice of young leaves watery, sometimes spicy or acid 68
67 Petioles 3-10 cm. long; visible bud-scales 2-3; tree-trunk
smooth PAPER MULBERRY (BROUSSONETIA)
67 Petioles usually not more than 3 cm. long; visible bud-scales
3-6; tree-trunk usually scaly MULBERRY (MORUS)
68 Leaves entire "V
68 Leaves lobed; lobes entire or toothed 86
68 Leaves variously toothed or wavy-margined ; not lobed 101
14
SIMPLE SPIRAL ENTIRE LEAVES
69 Leaves 15-30 cm. long; end-bud scaleless, others scaled, brown- hairy _ _ PAPAW (ASIMINA)
69 Leaves usually not more than 15 cm. long; if more, then end- bud scaled 70
70 Leaves palmately veined 71
70 Leaves pinnately veined 73
71 Upper side-veins curving towards tip of leaf ; trunk often warty
HACKBERRY (CELTIS)
71 Upper side-veins straight or curving towards side-margin ;
trunk not warty 72
72 Leaves silky on veins of under surface, spicy; leaf-scars not
fringed SPICE BUSH (BENZOIN)
72 Leaves usually hairless on under surface, not spicy; leaf-scars
fringed at top JUDAS-TREE, REDBUD (CERCIS)
73 Upper side-veins curving towards leaf-tip ; twigs greenish
DOGWOOD (CORNUS)
73 Upper side-veins straight or curving towards side-margin, or
else twigs not green ._ 74
74 Juice of leaves spicy '5
74 Juice of leaves not spicy 76
75 Twigs and bud-scales brown; stipule-scars absent
SPICE BUSH (BENZOIN)
75 Twigs and bud-scales green; stipule-scars present..(SASSAFRAS)
76 Mature leaves hairy on both surfaces ; young twigs hairy _ 77
76 Mature leaves hairless at least on upper surface 78
77 Winter-buds showing about 4 scales, all buds about same shape
PEAR (PYRUS)
77 Flower-buds showing about 12 scales, much larger than leaf- buds and of a different shape CORKWOOD (LEITNERIA)
15
78 Winter-buds scaleless, showing folded leaves
BUCKTHORN (RHAMNUS)
78 Winter-buds one-scaled; leaves sometimes downy on under
surface, not woolly WILLOW (SALIX) .
78 Winter-buds 10-scaled or more 79
78 Winter-buds less than 10-scaled, if one-scaled then leaves
woolly on under surface - 81
79 Winter-buds narrow, pointed, flaring away from twig; trunk
usually smooth, gray BEECH (FAGUS) ^
79 Above combination not present 80
80 One bundle-scar; end-bud much larger than side-buds
(RHODODENDRON) -
80 Several bundle-scars irregularly scattered; end-bud not dispro- portionately large
SHINGLE OAK, WILLOW OAK (QUERCUS) ,
81 Leaves about 4 times as long as wide ; under surface covered by a grayish mat of hairs ALTERNATE-LEAVED BUTTERFLY-BUSH (BUDDLEIA)
81 Leaves not usually 4 times as long as wide ; hairs sometimes
present 82
82 One compound bundle-scar forming a curved line
PERSIMMON (DIOSPYROS)
82 Three or more bundle-scars 83
83 Leaves woolly on under surface ; 1 or 2 visible bud-scales
QUINCE (CYDONIA)
83 Leaves sometimes downy, but not woolly; more than 2 visible
bud-scales - 84
84 Leaves arranged in 2 vertical ranks ; base of blades showing 3
almost equal veins HACKBERRY (CELTIS)
84 Leaves in more than 2 ranks ; veins not as described 85
85 Lower branches of tree usually drooping towards ground;
height of leaf-scars about half their length
SOUR GUM, BLACK GUM, PEPPERIDGE, TUPELO
(NYSSA)
85 Lower branches not drooping; leaf-scars narrower than those
just described PEAR (PYRUS) J
16
SIMPLE SPIRAL LOBED LEAVES
86 Leaves palmately veined ; palmately or irregularly lobed 87
86 Leaves pinnately veined; pinnately or irregularly lobed 90
87 Lobes entire; leaf 3-lobed at tip and 3-veined at base of blade
SPICE-BUSH (BENZOIN)
87 Lobes toothed 88
88 Lobes 5-7, finely toothed ; bark of branches sometimes showing
corky ridges SWEET GUM (LIQUIDAMBER) ^
88 Lobes 3-5, coarsely toothed ; bark not corky 89
89 Under surface of leaves bearing a w^hite mat of hairs
WHITE POPLAR (POPULUS)
89 Leaves with a few or no hairs on under surface
SHRUBBY ALTHEA (HIBISCUS)
90 Leaves mitten-shaped, with one or two "thumbs," varying from
oval to lobed on the same tree (SASSAFRAS) i
90 Leaves not mitten-shaped or varying as much as above 91
91 Winter-buds stalked, showing 2 or 3 scales; leaf-scars half- round or triangular, with 3 bundle-scars ALDER (ALNUS) ^^
91 Winter-buds not stalked, but spurs sometimes present 92
92 Leaves 2-ranked ^^
92 Leaves in more than 2 ranks 95
93 Winter-buds blunt and plump, showing more than 3 scales
HAZEL (CORYLUS)
93 Winter-buds usually sharp-pointed, somewhat plump, showing
2 or 3 scales 94
94 Leaves double-toothed; bark of trunk white or orange, spurs
sometimes present BIRCH (BETULA) ^
94 Leaves usually coarsely single-toothed; bark not white or
orange LINDEN, BASSWOOD (TILIA) :
95 Bud-scales 10 or more ; bundle-scars numerous, irregularly scat-
tered 96
95 Bud-scales not more than 10 ; bundle-scars 3 or in 3 groups 97
17
96 Tips of lobes of leaves rounded..WHITE OAK group (QUERCUS)
96 Tips of lobes of leaves pointed
RED and BLACK OAKS (QUERCUS)
97 Leaves usually double-toothed ; winter-buds often hairy or
sticky, woolly inside MOUNTAIN-ASH (SORBUS)
97 Leaves sometimes single-toothed; winter-buds sometimes
hairy, but not sticky or woolly 98
98 Stipule-scars present ; leaf-margins sometimes wavy 99
98 Stipule-scars absent ; margins always double-toothed 100
99 Tip of leaf 3-lobed ; teeth of margin not long-pointed
FLOWERING ALMOND (PRUNUS)
^ Tip of leaf not 3-lobed ; teeth of margin long-pointed
CHERRY (PRUNUS)
1(X) Second-year twigs purple-brown ; leaves 2-6 cm. long, wavy- margined, single-toothed, varying from unlobed to deeply lobed or compound ; both twigs and leaves eventually hair- less PEAR ( P YRUS)
100 Both twigs and leaves not as just described
CRABAPPLE (MALUS or PYRUS)
SIMPLE SPIRAL TOOTHED LEAVES
101 Leaves palmately veined 102
101 Leaves pinnately veined 105
102 Leaves with 5-7 almost equal veins at base of blade
(TETRACENTRON)
102 Leaves with 3 almost equal veins at base of blade 103
103 Leaves 10-15 cm. long, petioles 3-5 cm. long
JAPANESE RAISIN-TREE. HONEY-TREE (HOVENIA)
103 Leaves usually not more than 10 cm. long; petioles less than
3 cm. long 104
104 Leaves irregularly toothed, 3.5-8 cm. long ; bark of trunk gray,
peeling in long flakes (PTEROCELTIS)
104 Leaves usually untoothed near base ; bark smooth or with corky
warts HACKBERRY. SUGAR-BERRY (CELTIS)
18
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\
I
105 Trunk usually gray, smooth ; winter-buds tall, narrow, pointed,
many-scaled BEECH (FAGUS)
105 Trunk and winter-buds not as just described 106
106 Leaf-buds (not catkins) stalked 107
106 Leaf-buds not stalked, sessile Ill
107 Winter-buds scaleless, at least after sheathing stipules drop off 108 107 Winter-buds showing 2 or 3 scales 109
108 Leaves lop-sided at base ; widest above middle, wavy-toothed
WITCH-HAZEL (HAMAMELIS) 108 Leaves not particularly lop-sided at base ; usually widest near
middle, fine-toothed (SINOWILSONIA)
109 Leaf-buds hairy, red or scurfy; stipule-scars almost equal in
size ALDER (ALNUS)
109 Leaf-buds hairy but not red or scurfy; stipule-scars unequal.... 110
110 Leaves wavy-toothed above middle, oval, hairy on both sur- faces, petioles 2-6 mm. long (PARROTIA)
110 Leaves sharp-toothed, almost round, not hairy on upper surface
when mature, petioles 6-12 mm. long (PARROTIOPSIS)
111 End-bud scaleless, others 2-scaled ; bark gray, shredding
EPAULETTE-TREE (PTEROSTYRAX)
111 All buds scaleless (end and side) 112
111 All buds scaled 114
112 Buds usually superposed; leaf-margin usually faintly toothed
above middle - STORAX (STYRAX)
112 Buds solitary - 113
113 Leaves rounded at base of blade, widest near middle; leaf-scar crescent-shaped
CASCARA SAGRADA, INDIAN CHERRY (RHAMNUS) 113 Leaves pointed at base of blade, widest above middle; leaf-scar shield-shaped with flaring upper corners
FRANKLINIA (GORDONIA)
114 Winter-buds showing one scale WILLOW (SALIX)
114 Winter-buds (exclusive of catkins) showing more than one
scale 115
19
115 Lowest bud-scale directly above leaf-scar: at least one of fol- lowing conditions also present ; petiole flattened (at least at tip) at right angles to surface of blade, hairy or resinous winter-buds, woolly under-surface of leaf, yellow or red mid-rib POPLAR (POPULUS)
115 Above combinations not present 116
116 Winter-buds showing 2-4 scales 117
116 Winter-buds showing more than 4 scales 127
117 Leaf-scars showing only one bundle-scar (sometimes com-
pound) - 118
117 Leaf-scars showing 3 or more bundle-scars or groups of scars.. 121
118 Bark of trunk smooth, red, peeling in large flakes; winter-buds
sometimes superposed ; bundle-scar round, near top of leaf- scar WILD CAMELLIA (STEWARTIA)
118 Bark of trunk not as just described 119
119 Length of mature leaves about 4 times their width, under-sur-
face gray-woolly ; visible bud-scales 2 ALTERNATE-LEAVED BUTTERFLY-BUSH (BUDDLEIA)
119 Length of mature leaves not 4 times their greatest width; visi-
ble bud-scales usually 3 120
120 Winter-buds solitary; stipule-scars absent
WHITE ALDER (CLETHRA)
120 Winter-buds sometimes superposed; stipules or stipule-scars
present HOLLY (ILEX) ^
121 End-bud present 122
121 End-bud usually absent except on spurs 123
122 Leaf-margin bearing bristle-like teeth; twigs usually round;
stipule-scars equal in size..WINTER HAZEL (CORYLOPSIS) 122 Leaf-margin irregularly and sharply toothed ; twigs often
3-sided ALDER (ALNUS)
122 Leaf margin coarsely toothed and sometimes bristled; twigs
often ridged ; stipule-scars unequal in size
CHESTNUT (CASTANEA)
123 Leaves 5-8 cm. long, in more than 2 ranks, margin finely tooth-
ed; bark of trunk flaky
FLOWERING QUINCE (CHAENOMELES) 123 Leaves 2-ranked, at least on horizontal twigs 124
20
124 Leaves with 3 almost equal veins near base of blade
HACKBERRY, SUGAR-BERRY (CELTIS)
124 Leaves strictly pinnate, not as just described 125
125 Leaves narrow-oval or oblong, coarsely toothed and sometimes
bristled CHESTNUT (CASTANEA)
125 Leaves somewhat heart-shaped or broad-oval or triangular, not
bristled, often finely toothed 126
126 Leaves broad-oval or triangular, not usually lop-sided, margin
irregularly and often doubly toothed ; bark of trunk whitish or brightly colored or dark, smooth or peeling or broken into scales; lenticels often stretched sidewise; spurs com- mon BIRCH (BETULA)
126 Leaves broad-oval or heart-shaped, usually lop-sided at base of
blade, margin usually regularly toothed ; bark dark, other- wise not as just described; lenticels not stretched; spurs not common LINDEN, BASSWOOD (TILIA)
127 Bundle-scars a dozen or so, irregularly scattered
OAK (QUERCUS)
127 Bundle-scars 6-8, in horizontal line across top of leaf-scar ; bud- scales hairy at base (EUPTELEA)
127 Bundle-scar one 128
127 Bundle-scars 3-5 130
128 Winter-buds superposed, showing about 4 fleshy scales
SNOWDROP-TREE, SILVER-BELL TREE (HALESIA)
128 Winter-buds not as just described 129
129 Leaves 8-20 cm. long, distinctly toothed, with an acid taste;
winter-buds solitary
SORREL-TREE, SOURWOOD (OXYDENDRUM)
129 Leaves less than 8 cm. long unless teeth are very faint, sweet-
tasting; winter-buds solitary or superposed
SWEETLEAF (SYMPLOCOS)
130 Height of largest buds about 3 or 4 times their width 131
130 Height of largest buds less than 3 times their width 132
131 Winter-buds hairy or sticky, woolly inside; bud-scales not
twisted ; leaves irregularly or doubly toothed
WHITE BEAM-TREE, MOUNTAIN-ASH (SORBUS) 131 Winter-buds not as just described; bud-scales sometimes twist- ed; leaves singly toothed SHADBUSH (AMELANCHIER)
21
u^
132 End-bud present 133
132 End-bud absent 139
133 Leaves 8-14 cm. long, bright-green on upper surface, hairy on under surface, somewhat heart-shaped, teeth single, long- pointed, petioles 3.6-7 cm. long; bud-scales about 6 in num- ber, pale-bordered (DAVIDIA)
133 Leaves not as just described 134
134 Stipules or stipule-scars present 135
134 Stipules and stipule-scars absent or indistinguishable 137
135 Winter-buds solitary but often crowded at tip of twig; leaves
not as described below CHERRY (PRUNUS)
135 Three winter-buds in an axil on flowering twigs ; twigs often
red or green ; length of leaves usually at least 3 times their width, shape tapering from middle to tip 136
136 Leaves typically widest below middle and petioles 1.5-2.5 cm.
long ALMOND (PRUNUS)
136 Leaves typically widest at or below middle and petioles not
more than 1.5 cm. long; leaves often curved and hanging down PEACH (PRUNUS)
137 Twigs hairy; leaves hairy at least on under surface, oblong,
6-12 cm. long, finely toothed or nearly entire ; buds dark- brown - MEDLAR (MESPILUS)
137 Twigs and leaves not as just described 138
138 Buds usually pointed and flaring from twig; bud-scales slightly
pointed, without a border; leaves single-toothed, often hair- less PEAR (PYRUS)
138 Buds oval, blunter than those described above, appressed, often
red and hairy; bud-scales sometimes blunt and bordered; leaves usually irregularly or doubly toothed
APPLE, CRABAPPLE (MALUS or PYRUS)
139 Buds usually blunt, catkins present ; leaves somewhat heart-
shaped, sometimes doubly toothed HAZEL (CORYLUS)
139 Buds usually sharp-pointed, if blunt then no catkins present,
catkins not always present with sharp buds 140
140 Winter-buds showing 4 or more scales ; scales ridged and bris-
tled; leaves largest above middle, single-toothed, hairy on
under surface (PHOTINIA)
140 Winter-buds not as just described 141
22
L
V-
141 Leaves in more than 2 ranks 142
141 Leaves 2-ranked 145
142 No stipule-scars visible 143
142 Stipule-scars present 144
143 Twigs warty; bud-scales often pitted; leaves somewhat heart-
shaped, with double, long-pointed teeth
MADDEN CHERRY (MADDENIA)
143 Twigs not warty; both scales and leaves not as just described
137 and 138
144 Buds showing dark scales with white hairs around the margin
APRICOT (PRUNUS)
144 Scales of buds without contrasting white hairs, sometimes
pitted PLUM (PRUNUS)
145 Bud-scales numerous, arranged in 4 ranks 146
145 Bud-scales about 6 in number, in 2 ranks or spiral 147
146 Leaves single-toothed; bark of trunk scaly (ZELKOVA)
146 Leaves irregularly or doubly toothed ; bark of trunk gray, ridg-
ed like muscles on an arm
HORNBEAM, BLUE BEECH (CARPINUS)
147 Bud-scales striped vertically; catkins often present; leaves not
very lop-sided at base of blade
IRONWOOD, HOP-HORNBEAM (OSTRYA) 147 Bud-scales not striped, but smooth or hairy; catkins not pres- ent; leaves lop-sided at base of blade ELM (ULMUS)
COMPOUND LEAVES
148 Most or all leaves made up of only 3 leaflets 149
148 Most or all leaves made up of more than 3 leaflets 153
149 Leaves opposite, but not always quite on the same level 150
149 Most or all leaves spirally arranged _ 151
150 Winter-buds showing 2 or 4 scales; leaflets finely toothed; up- per margin of leaf-scars almost straight
BLADDERNUT (STAPHYLEA)
150 Winter-buds many-scaled and leaflets variously toothed, or 2- or 4-scaled and leaflets coarsely or doubly toothed ; upper
margin of leaf-scars curving down MAPLE (ACER)
23
151 Leaflets showing no almost transparent dots in their blades 152
GOLDEN-CHAIN (LABURNUM) 151 Leaflets showing such dots 152
152 Twigs green, with a spine at each node ; buds hairless, red
HARDY ORANGE (PONCIRUS) 152 Twigs tan-colored, spineless ; buds hairy....HOP-TREE (PTELEA)
153 Leaves palmately compound 154
153 Leaves pinnately compound 156
153 Leaves bipinnately (twice) compound 180
154 Leaves spirally arranged (ACANTHOPANAX)
154 Leaves oppositely arranged 155
155 Mature leaves more than 10 cm. wide; winter-buds showing more than 4 scales
HORSE-CHESTNUT, BUCKEYE (AESCULUS) 155 Mature leaves 5-10 cm. wide; winter-buds showing 2 or 3 scales
MAPLE (ACER)
156 Leaves opposite but not always quite on the same level 157
156 Leaves spirally arranged - 161
157 Leaflets showing almost transparent dots in their blades 158
157 Leaflets showing no such dots 159
158 Each winter-bud almost surrounded by petiole of leaf; leaf-
scars horseshoe-shaped-.CORK-TREE (PHELLODENDRON)
158 Each winter-bud exposed in axil of leaf; leaf-scars broadly
crescent-shaped (EVODIA)
159 Leaflets coarsely toothed, some usually lobed; upper margin
of leaf-scar curving down; bundle-scars not more than 7; winter-buds 2-scaled BOX-ELDER (ACER)
159 Leaflets never lobed, not always coarsely toothed; bundle-scars
more than 7 if upper margin of leaf-scar curves down 160
160 Buds showing 3 or more pairs of scales ; upper margin of leaf-
scar curving up; bundle-scars not more than 7
ELDER (SAMBUCUS) 160 Winter-buds showing 1-3 pairs of scales; upper margin of leaf- scar straight or curving down; bundle-scars more than 7
ASH (FRAXINUS)
24
161 Leaf made up of an even number of leaflets 162
161 Leaf made up of an odd number of leaflets I"'*
162 Tree unarmed; leaflets 10-22 in number, 8-15 cm. long
FALSE CEDAR (CEDRELA)
162 Tree spiny or prickly 1°^
163 More than one partly concealed bud in a leaf-axil; usually a
spine above the axil and spines on older branches and the
trunk HONEY-LOCUST (GLEDITSIA)
163 Only one bud in an axil; no spines on trunk, spines at each side
of leaf-scar, representing stipules....PEA-TREE (CARAGANA)
164 Twigs prickly or spiny
165
164 Tree unarmed 1^6
165 Leaflets showing almost transparent dots in blades
PRICKLY ASH (ZANTHOXYLUM) 165 Leaflets without such dots LOCUST (ROBINIA)
166 All leaflets alternate on rachis
YELLOW-WOOD (CLADRASTIS)
166 Most leaflets exactly or almost opposite on rachis 167
167 Leaf-margin entire except for 2-4 coarse teeth near base ; leaf-
lets 13-35 in number, 7-15 cm. long
TREE OF HEAVEN (AILANTHUS)
167 Leaf-margin entire or wavy ^"^
167 Leaf-margin toothed and sometimes lobed 172
168 Twigs, petioles and rachis reddish-brown with sticky hairs
CLAMMY LOCUST (ROBINIA) 168 Twigs, petioles and rachis not as just described 169
169 Some leaflets more than 8 cm. long or else juice of young leaves
milky - ^^^
169 No leaflets more than 8 cm. long 171
170 Rachis winged or leaves crowded at tip of twig; winter-buds solitary; 7-21 leaflets, juice of young leaves milky; some species POISONOUS SUMAC (RHUS)
170 Rachis never winged ; leaves sometimes crowded at tip of twig, but buds superposed ; 5-9 leaflets, juice watery
ENGLISH WALNUT (JUGLANS)
25
171 Leaflets not usually more than 5 cm. long, usually with hairs or prominent veins on the under surface; buds superposed, partly concealed by leaf-scar
JAPAN PAGODA-TREE (SOPHORA)
171 Leaflets 2-8 cm. long, not always hairy; winter-buds solitary,
showing 2 or more often pale-margined scales (MAACKIA)
172 Leaves irregularly and coarsely toothed, sometimes lobed
PRIDE OF INDIA, VARNISH-TREE (KOELREUTERIA)
172 Leaves toothed regularly although sometimes slightly, not lobed 173
173 Leaflets not more than 13 HICKORY (CARYA)
173 Leaflets 7-31 174
174 Buds often scaleless ; juice of young leaves usually sticky or
milky - SUMAC (RHUS)
174 Buds and juice both not as just described 175
175 Under surface of leaflets paler than upper, leaflets usually hair-
less when mature : 1'^
175 Both surfaces of about the same shade or else hairy 177
176 Height of buds more than twice their width ; leaf-scar narrow
with down-curved upper margin
MOUNTAIN-ASH (SORBUS)
176 Height of buds not twice their width; leaf-scar wide, upper
margin almost straight
CHINESE BUCKEYE (XANTHOCERAS)
177 Leaflets 4-10 cm. long, doubly toothed (PLATYCARYA)
177 Leaflets usually single-toothed, or else more than 10 cm. long.. 178
178 Lower margin of leaf-scar raised prominently above twig ; ma-
ture leaves hairy on under surface, especially on mid-rib and in axils of veins....WALNUT, BUTTERNUT (JUGLANS) 178 Lower margin of leaf-scar not much raised ; mature leaves not
so hairy as above 1'"
179 Buds 2-scalcd ; bundle-scars several, in 3 groups
PECAN (CARYA)
179 Buds usually scaleless; bundle-scars 3, hooked or curved
WING-NUT. CAUCASIAN WALNUT (PTEROCARYA)
26
TWICE-COMPOUND LEAVES
180 Leaflets about 6 mm. long, 40-60 to a pinna
SILK-TREE, JULIBRIZZIN (ALBIZZIA)
180 Leaflets usually longer, or if shorter then not so many to a
pinna - ^°^
181 Margin of leaflets entire or wavy 182
181 Leaflet-margin distinctly toothed and sometimes lobed 183
182 Tree usually spiny ; lowest pinnae compound like the others
HONEY-LOCUST (GLEDITSIA)
182 Tree unarmed; lowest pinnae are simple leaflets
KENTUCKY COFFEE-TREE (GYMNOCLADUS)
183 Bark prickly ; leaves 40 cm. to 1 meter long
ANGELICA-TREE, HERCULES' CLUB (ARALIA)
183 Bark unarmed ; leaves up to 35 cm. long
VARNISH-TREE, PRIDE OF INDIA (KOELREUTERIA)
27
1
2 3 4 5
«
7
8
0
10
11
12
13
14
15
/3
CHARACTERS OF LEAVES AND TWIGS
simple notted-velned leaf with bud in its axil, wavy-margined.
Opposite stalked l)uds, 4-ranl<ed; lenticels on stem.
Spiral scBsile side-buds, 3-ranked.
Compound Imndle-scars forminji: a line.
Whorled leaf-scars; bundle-scars dots.
Superposed buds.
Spike-like evergreen leaves, 3-ranked.
Leaf-cushions.
Scale-like evergreen leaves.
Needle-like evergreen leaves.
rinnnlely veined leaf, (louble-tootlied,
Palmatt'ly veined leaf, lobed, coarsely
I'iiinatcly compound leaf, leaflets odd in nuinlier, entire, alternate.
Hipinnately compound leaf, leaflets even in number, opposite.
Palmately compound leaf, singly flne-tootbed.
28
base lop-sided, toothed.
EXPLANATION OF TERMS AS USED IN THE KEY
ALTERNATE ARRANGEMENT. Only one leaf, leaflet or leaf-scar at
a node. Literally : 2-ranked. ANGLED MARGIN. Not entirely curved. With some straight places
and corners.
APPRESSED. Lying closely to the twig; usually flat.
ARRANGEMENT. See LEAF ARRANGEMENT.
AXIL. The angle made with the twig by the upper surface of the leaf, or by the upper margin of the leaf-scar.
BARK. The woody outside covering of a tree. As the part covered grows in diameter the bark must stretch or split. If it stretches it remains almost smooth and the lenticels are pulled sidewise, so that they form horizontal lines instead of dots. If the baiik splits it be- comes rough or scaly or furrowed.
BARK SCALES. The pieces into which bark sometimes breaks. They may be large or small; and they may remain on the tree, or flake of? in pieces, or peel either up and down or around the stem.
BASE. The inner or lower end, as of a leaf or a twig. The opposite of TIP.
BIPINNATELY COMPOUND. Twice or doubly compound. A pin- nately compound leaf made up of leaflets most or all of which are themselves pinnately compound.
BLUNT. Rounded. The opposite of POINTED.
BRANCHES. The twigs of a few years ago. The side divisions of the main stem.
BRISTLES. Stiff hairs.
BUDS. See WINTER-BUDS.
BUD-SCALES. The coverings of buds. Winter-buds may be scale- less or may have from one to many scales. If there are only twq they usually meet without overlapping. If there are several they resemble shingles on a roof. The KEY refers to the largest buds (exclusive of catkins), and considers only those scales which are visible from a single point of view.
BUNDLE-SCARS. The dots or lines found in a leaf-scar. They in- dicate the location of strands which were concerned with the food supply of the leaf. They are best examined in a leaf-scar of a pre- vious year, and if obscured by dirt will show more clearly if scratch- ed by a knife or a finger-nail.
CATKIN. A usually long, narrow flower-cluster; ex. willow. Here it is used to denote the bud containing the cluster. A catkin is not included in the descriptions of winter-buds, as it differs so decidedly in size, number of scales, etc.
CLASPING. Growing around an object.
CLEFT. Having a wedge-shaped hole.
29
CM. The abbrevation of centimeter, a unit of length equal to 2/5 of an inch. Two connected figures, as 2-6, mean that the range of size
includes both 2 and 6.
COMPOUND BUNDLE-SCAR. Made up of several scars, whether ap- parent or not.
COMPOUND LEAF. A leaf whose blade is divided into parts called leaflets. Each leaflet may have a stalk, or petiolule ; stipels, cor- responding to stipules ; and of course a blade. As distinguished from a simple leaf on a twig, a leaflet has no bud in its axil.
CONE-SHAPED. A round, hollow base with sides tapering up to a point.
CULTIVATED TREE. Tended by man. Applied to native or import- ed trees.
CUSHION. See LEAF-CUSHION.
DECIDUOUS LEAVES. Remaining only one growing season. Fall- ing usually in the autumn, like maple and elm, and at the latest in early spring. Thus the term here includes semi-evergreen. De- ciduous leaves are found only on twigs of the present season (in- cluding spur-tips).
DECURRENT. Continued down the twig, towards its base.
DOUBLE-TOOTHED. Each tooth cut into one or more smaller teeth.
DOWNY. Bearing soft, short hairs.
ENCIRCLING. Making a circle around.
END-BUD. A bud which covers the tip of the twig. See SIDE-BUD.
ENTIRE. A margin without teeth or indentations.
EVERGREEN. Remaining longer than one growing season. Eventu- ally falling in two or more years. Found alive in winter and on twigs of the present and of some of the past seasons.
FLAKY. Falling oflF in small pieces.
FLARING AWAY. Pointing away at an angle from the part bear- ing it.
FLESHY. Not hard or dry ; soft and watery.
FOUR-SIDED. The easiest way to detcrmnie this in a leaf is to cut the leaf across at the widest place and look down on the cut end. In a twig the angles may usually be seen or felt.
FRINGED. Edged with fine hairs.
FURROWED. Marked like plowed ground with alternate longitudinal ridges and grooves. The ridges and grooves usually intersect.
GENERA. The plural of genus. See GENUS.
GENUS. The plural is genera. A genus, like a species, is hard to de- fine, but easy to illustrate. Examples of genera are oaks, maples, etc. In writing the scientific name the genus name is placed first.
GLAND. Usually seen as a tiny lump or nodule.
GROWING SEASON. From spring to autumn for deciduous trees, most of the growth occurring by middle summer.
30
HAIRY. Here applied to any kind of hair. See also DOWNY and WOOLLY.
HALF-ROUND LEAF-SCAR. The upper margin straight and the lower a semi-circle.
HARDY. Able to withstand, without special protection, the extremes of temperature in the regions named.
HEART-SHAPED. Here used to denote a broad-oval leaf with a rounded or two-lobed base and a long tip.
HYBRID. A plant resulting from a cross between two parents of different genera, species or varieties. This KEY includes practically no hybrids.
IMMATURE PLANTS. Young plants which have not yet attained the size and characteristics of full-grown ones. They should not be ex- amined with this KEY because they often differ so decidedly from the characteristics of their elders. Young trees may usually be recognized as such by their small size and unusually large leaves and buds.
INTERNODE. The part of a stem between two joints (nodes). Sometimes covered by leaves, but marked then by the space be- tween the bases of the leaves in a vertical row, since leaves grow only at nodes.
IRREGULARLY TOOTHED. Teeth unequal in size and distance apart.
KEEL. A longitudinal ridge.
LEADING SHOOTS. The main-stem and the branches themselves— not side-branches or twigs.
LEAF. See LEAVES.
LEAF-ARRANGEMENT. The position of leaves on a twig. (See OPPOSITE and SPIRALLY ARRANGED.) The leaves to be de- termined should be those on a rapidly growing horizontal twig ; not a young shoot.
LEAF-AXIL. See AXIL.
LEAF-CUSHION. The raised base of the leaf, adherent to the twig; forming a platform which may be seen readily in old twigs from which the leaves have dropped off.
LEAFLET. A section of the blade of a compound leaf.
LEAF-SCAR. The mark left on a twig by a leaf when it falls. The shape reproduces the outline of the part of the leaf (petiole or base of blade) which touched it. Leaf-scars are best studied in a twig of the previous season, as those left by living leaves which have been pulled off are incomplete and difficult to decipher. For the marks in a leaf-scar see BUNDLE-SCARS.
LEAVES. Typically the parts of a plant which form the foliage. In a deciduous tree they are thin and flat and expanded. In an ever- green tree they may be small scales or little spikes or needles, or leaves in shape like those of deciduous trees. They are usually thick and tough. A leaf consists typically of a stalk or petiole ; of a broader part, the blade; and of two stipules, little leafy append-
31
ages at the base of the petiole. Any one of these parts may be missing or transformed into something with a different appearance, as a spine. The stipules, even if originally present, usually fall off before very long. Leaves grow at nodes on the twigs, and theor- etically each has one bud in its axil.
LENTICELS. The breathing pores of the stem. Seen usually as dots on twigs, but occasionally forming horizontal lines because of the stretching of the bark as the branch grows in diameter.
LOBED. A margin with indentations deeper than teeth but not ex- tending to the midrib or the petiole. A lobe is a section between two indentations.
LONG. Refers, in a leaf, to the distance from the twig to the tip of
the blade. LONGITUDINAL. The direction from base to tip.
LOP-SIDED. Unequally divided at the base (of a leaf) by the midrib.
LOWER. See UNDER.
MARGIN. The boundary line of the blade of a leaf or of a bud-scale.
MATURE. Full-grown. Mature leaves are to be found a little way back from the tip of the twig, not at the tip itself. All are usual- ly of much the same shape, but not always of the same size. Ma- ture buds are developed by late summer.
METER. One hundred centimeters. It equals about 40 inches, or 3 1/3 ft.
MIDDLE. Halfway up the side margins.
MIDRIB. A prominent vein running longitudinally through the cen- ter of the blade of a leaf; often better seen on the under surface than on the upper surface.
MM. Abbreviation for millimeter. 1/10 of a centimeter. 1/1000 of a meter.
NEEDLE-LIKE LEAVES. NEEDLES. Very narrow evergreen leaves with almost parallel side margins. The needles may be round like a thread-needle or flat like a tape-needle. They may be sharp- pointed or blunt.
NETTED-VEINED. With the smallest veins interlacing. Best seen by holding the leaf up to the light and looking through it.
NODE. A joint on a stem (branch or twig) at which one or more leaves and buds grow or have grown. Each leaf should have one or more buds in its axil.
NOTCHED. The tip of the leaf having a little v-shaped slit where the tip might have been ; not pointed.
OBLONG LEAF. Side margins tending to be parallel for at least part of their length. Leaves wider than those called needles.
OPPOSITE. Two leaves or twigs facing each other at a node on a stem. The next pair (if leaves) will be at right angles to the first, making four vertical ranks up and down the stem. The next pair but one will be over the first pair.
22
ORGAN. Stem, leaf, bud, etc.
OUTER. The direction away from the base of the leaf or the twig.
OVAL LEAF. Here used to indicate either an ellipse, like the letter O, or an egg-shaped figure. In any case the opposite margins curve and the leaf is not so narrow as an oblong leaf. PALMATELY COMPOUND. Divided into leaflets radiating from the tip of the petiole and separate from each other. The leaflets are pinnately veined. PALMATELY LOBED. A margin deeply cut into segments which are united at the base of the leaf like fingers at the palm of a hand. Palmately veined. PALMATELY VEINED. Several large veins of almost equal size ra- diating from the base of the leaf. PARALLEL-VEINED. The smallest veins in the leaf running almost in the same direction. Contrasted with netted-veined. Best seen by holding a leaf up to the light and looking through it. PEG. A stif? stalk attached more closely to the cushion from which it grows than to the leaf which it supports. Often a different color from the leaf proper. PETIOLE. The stalk of the leaf; belonging to it and falling with it in
simple leaves. Not all leaves have petioles. PINNA. Here used to denote that part of a doubly compound leaf which corresponds to a leaflet. It is usually made up of secondary leaflets. PINNATELY COMPOUND. Divided into leaflets which are separate from each other but united to the rachis (the part which corre- sponds to the midrib). PINNATELY LOBED. Having deep indentations which run almost to
the midrib of a pinnately veined leaf. PINNATELY VEINED. Feather-like. Having a strong central vein,
the midrib, from which branch side veins. PITTED. Marked with little spots or holes. POINTED. Sharp-tipped. PRICKLE. A sharp-pointed outgrowth of the outer covering of a twig
or branch. Not usually found at a node. RACHIS. The middle part of a pinnately compound leaf. The leaflets
are attached to it. It corresponds to the midrib of a simple leaf. RANKS. The longitudinal rows in which leaves and leaf-scars are ar- ranged. To determine use a string as described in SPIRALLY ARRANGED, or look down the twig from the tip. RESINOUS. Here used as a synonym of sticky. The substances re- ferred to as resin are found especially in young leaves, buds and twigs. They are often located in dots on the leaf-blade. SCALELESS. Without bud-scales. The contents are visible, but are usually so covered with hairs that their outlines are obscured and they are sometimes taken for fuzzy scales.
33
SCALES. See BUD-SCALES, SILVERY SCALES, BARK SCALES, SCALES (LEAVES).
SCALES (LEAVES). Usually evergreen. Small, usually overlapping like shingles, pressed against the twig so as to cover it ; opposite margins not parallel, often curved ; too broad and curved to resem- ble spikes.
SCURFY. Coated with small scales or granules.
SESSILE. Literally, sitting. Growing directly from the twig (if leaves) without petiole.
SHAPE. Outline as traced by the margin of a surface.
SHEATHING. Enveloping.
SHREDDING. Peeling off in strips.
SHRUB. A bushy woody plant having several stems instead of one trunk ; often less than 12 ft. (4 m.) high.
SHRUBBY. Broad and low, but fulfilling the requirements for a tree,
SIDE-BUD. A bud growing from the side of the twig. The top side- bud often looks like an end-bud, but may be told from it, if the end- bud is absent, by the tip of the stem alongside it.
SILVERY SCALES. Tiny flakes, sometimes glistening, found on twigs, leaves and buds.
SIMPLE LEAVES. Blade undivided into separate sections; indenta- tions, if any, not reaching to midrib. A simple leaf differs from a leaflet because it has a bud in its axil.
SOLITARY BUD. Only one bud in a leaf-axil.
SPECIES. A division of a genus. The word is the same in singular and plural. Hard to define, but easy to illustrate. Ex. a sugar ma- ple is a species of the genus maple. In writing the scientific name the species name stands after that of the genus and usually begins with a small letter. This KEY does not extend to species. They may be found in the books listed under REFERENCES.
SPIKES, SPIKE-LIKE, SPIKY. Having sides which slant towards each other, making a sort of long triangle. Spikes usually flare away from the twig.
SPINE. A sharp-pointed projection or thorn which takes the place of a leaf, a bud, or a twig; and so is located at or near a node, or at the end of a twig.
SPINY-POINTED, SPINY-TOOTHED. The tip or the teeth of the leaves ending in sharp, pricking projections.
SPIRALLY ARRANGED. Only one leaf at a joint on a twig. A string touching such a leaf and then going in turn to each leaf above it would make a spiral. If the third and first leaves were in the same straight line the arrangement would be two-ranked. If the fourth leaf were over the first the arrangement would be three- ranked, etc. Four ranks are never found in a spiral arrangement.
34
SPUR. A dwarf branch, sometimes modified to form a spine. Since the dwarf branch grows little in length, such leaves or leaf-scars as it bears are crowded and their arrangement is difficult to make out. Reference should be made to a young, rapidly growing twig.
STALKED BUD. A bud raised above the twig on a Httle stem. Since only one leaf or leaf-scar is found it is distinguished from a spur.
STEM. Includes trunk, branches and twigs. Most winter-buds develop into twigs and so are embryo stems.
STIPULES. The more or less leafy outgrowths at the base of a leaf. Sometimes there are none, sometimes they drop ofT very early and leave a scar, sometimes they are attached to the petiole and so leave no trace after it drops, sometimes they are seen as spines, and often they form scales of winter-buds.
STIPULE-SCARS. The tiny, more or less horizontal marks often found at each side of the leaf-scar after the stipules have dropped off. If the stipules were very large the scars may meet around the twig, forming a ring. Sometimes they are unequal in size.
SUPERPOSED BUDS. Two or more buds arranged one over another.
SURFACE. The outside of a leaf or other part of a tree.
TIP. The outer end of the leaf or twig; the part farthest from the stem. The opposite of BASE.
TOOTHED. A margin cut into points. As used here it implies single points (see DOUBLE-TOOTHED). Not mdented deeply enough to make lobes.
TREE. Here considered to be a woody plant at least 13 ft. (4 meters) high, having one main trunk, which branches into others at a per- ceptible distance from the ground. Plants which are ordinarily shrubs are included in the KEY if they have these characteristics.
TRUNK. The lower part of a tree before it breaks up into branches. Sometimes it runs through the tree, giving off branches on the sides.
TWICE COMPOUND. See BIPINNATELY COMPOUND.
TWIG. Here applied to the most recent growth of the stem, the end of a branch, unless qualified by such a word as "older." It is mark- ed at the outer end by a winter-bud or by its own tip, and at the inner end by a series of encircling rings which are the remains of the winter-bud which gave rise to it.
UNARMED. Without spines or prickles.
UNDER. The direction towards the bottom or the inside of the tree.
UPPER. The direction towards the top or the outside of the tree.
USUALLY. Implies "not always." Indicates that there is at least one species which does not agree with the description.
VARIETIES. Sub-divisions of species, differing only slightly and un- essentially from well-marked species. They are not included in this
35
VEINING. The arrangement of the strands which conduct the food supply. Often forming ridges, especially on the undersurface of a leaf. The largest veins determine whether a leaf is pinnately or palmately veined; and the smallest ones whether it is parallel- or netted-veined.
VISIBLE. Seen from one point of view without turning the object.
WARTY. Bearing roundish lumps of bark.
WAVY. A margin which is not quite entire ; scalloped or uneven ; not sharp-toothed.
WEDGE-LIKE, WEDGES. See SPIKE.
WHORLED. An arrangement of more than two leaves at a node.
WIDTH. The distance across the surface of a leaf from one side mar- gin to the other. The term implies the greatest width. Also the distance from one end of a leaf-scar to the other across the twig.
WILD. Growing without care from man. Applied principally to native trees.
WINGED RACHIS. A rachis with a thin flat border on each side.
WINTER-BUDS. Those buds which remain on the trees all winter. As some of them were contained in the winter-buds of the previous year they can be seen, if they are not concealed under the bark, as soon as those buds open in the Spring. They reach their full size and mature texture in the summer. For examination purposes un- opened buds of the previous year may often be found. The KEY descriptions refer to the largest buds, with the exceptions of cat- kins.
WOOLLY. Densely hairy, with long, interwoven hairs.
YEAR'S GROWTH. This begins with several encircling scars, the re- mains of a bud of the previous year. It ends with similar scars; or, if the newest wood, with an end-bud, or a top side-bud and the tip of the twig. The most recent year's growth usually differs from the others in the appearance of the bark.
36
INDEX
The numbers refer to the sections.
ABIES, 21.
ACANTHOPANAX, 54, 154. ACER, Z7, 39, 46, 47, 150, 155, 159. AESCULUS, 155. AILANTHUS, 167. ALBIZZIA, 180. ALDER, 91, 109, 122. ALMOND, 136. ALNUS, 91, 109, 122. ALTERNATE-LEAVED BUTTERFLY-BUSH, 81, 119. ALTHEA, SHRUBBY, 89. AMELANiCHIER, 131. AMERICAN SMOKE-TREE, 66. ANGELICA-TREE, 183. APPLE, 138. APRICOT, 144. ARALIA, 183. ARBOR VITAE, 29. ASH, 160. ASIMIiNA, 69. BALD CYPRESS, 32. BASSWOOD, 94, 126. BEAM-TREE, WHITE, 131. BEECH, 65, 79, 105, 131. BENZOIN, 72, 75, 87. BETULA, 94, 126. BIG-TREE, CALIPORNIA, 2Z. BIRCH, 94, 126. BLACK GUM, 85. BLACK-HAW, 40. BLACK OAK group, 96 : BLADDERNUT, 150. BLUE BEECH, 146. BOX, 4.
BOX-ELDER, 159. BROUSSONETIA, 67. BUCKEYE, 155. BUCKTHORN, 41, 78. BUDDLEIA, 81, 119. BUFFALO-BERRY, 42. BULL BAY, 5.
BUTTERFLY-BUSH, 81, 119. BUTTERNUT, 178. BUTTON-BUSH, 48. BUXUS, 4.
CALIFORNIA BIG-TREE, 23. CAMELLIA, WILD 118.
CARAGANA, 163. CARPINUS, 146. CARYA, 173, 179. CASCARA SAGRADA, 113. CASTANEA, 122, 125. CATALPA, 50.
CAUCASIAN WALNUT, 179. CEDAR, 13. CEDRELA, 162. CEDRUS, 13. CELTIS, 71, 84, 104, 124. CEP.HALANTHUS, 48. CEPHALOTAXUS, 20. CERCIDIPHYLLUM, 2,7. CERCIS, 72. OHAENOM'ELES, 123. CHAMABCYPARIS, 26, 29. CHERRY, 99. CHERRY LAUREL, 8. CHESTNUT, 122, 125. CHINA- FIR, 18. CHINESE BUCKEYE, 176. CHINESE LARCH, 2,Z. CmO'NANTHUS, 48. CHITTAM-WOOD, 66. CHRIST-THORN, 55. CLADRASTI'S, 166. CLAMMY LOCUST, 168. CLERODENDRON, 50. CLETHiRA, 120. CORK-TREE, 158. CORKWOOD, 77. CORNUS, 43, 73. CORYLOPSIS, 122. CORYLUS, 93, 139. COTINUS, 66. CRABAPPLE, 58, 100, 138. CRATAEGUS, 58. CRYPTOMERIA, 14, 23. CUNNINGHAMIA, 18. CUPRESSUS. 25. CYDONIA, 83. CYPRESS, 25. DAVIDIA. 133. DIOSPYROS, 82. DOGWOOD. 43, 72,. DOUGLAS FIR, 21. ELDER, 160.
27
ELEAGNUS, 52. ELM, 147.
EMPRESS-TREE, 49. ENGLISH WALNUT, 170. EPAULETTE-TREE, 111. EUOOMMIA, 66. EUPTELEA, 127. EVODIA, 158. EVONYMUS, 41. FAGUS, 65, 79, 105. FALSE ARBOR VITAE, 28. FALSE CEDAR, 162. FALSE CYPRESS, 26, 29. FIR, 21.
FLOWERING ALMOND, 99. FLOWERING QUINCE, 123. FORBSTIERA, 38. FRAGRANT OLIVE, 4. FRANKLINIA, 113. FRAXIiNUS, 160. FRINGE-TREE, 48. GINKGO, 31. GLEDITSIA, 163, 182. GOLDEN-CHAIN, 151. GOLDEN LARCH, 33.
GORDONIA, 113.
GUM, BLACK, 85.
GUM, SOUR, 85.
GUM, SWEET, 88.
GYMNOCLADUS, 182.
HACKBERRY, 71. 84, 104, 124.
HACKMATACK, 33.
HALESIA, 128.
HAMAMELIS, 108.
HARDY ORANGE, 152.
HAW, BLACK-, 40.
HAWTHORN, 58.
HAZEL, 93, 139.
HEMIPTELEA, 59.
HEMLOCK, 17.
HERCULES' CLUB, 183.
HIBA ARBOR VITAE, 28.
HIBISCUS, 89.
HICKORY, 173.
HTPPOPHAE, 52.
HOLLY, 6, 7, 120.
HONRY-LOCUST, 163, 182.
HONEY-TREE, 103.
HOP-HORNBEAM, 147.
HOP-TREE, 152. HORNBEAM, 146.
HORSE-CHESTNUT, 155.
HOVENIA, 103.
ILEX, 6, 7, 120.
INCENSE CEDAR, 27.
INDIAN BEAN, 50.
INDIAN CHERRY, 113.
IRONWOOD, 147.
JAPAN PAGODA-TREE, 171.
JAPANESE CEDAR, 14, 23.
JAPANESE RAISIN-TREE, 103.
JUDAS TREE, 72.
JUGLANS, 170, 178.
JUJUBE, 55.
JULIBRIZZIN, 180.
JUNIPER, 13, 26.
JUNIPERUS, 13, 26.
KALMIA, 11.
KATSURA-TREE, 37.
KENTUCKY COFFEE-TREE, 182.
KOELREUTERIA, 172, 183.
KUSAGI, 50.
LABURNUM, 151.
LARCH, 33.
LARIX, 33.
LEITNERIA, 77.
LIBOCEDRUS, 27.
LILAC, 45.
LINDEN, 94, 126.
LIQUIDAMBER, 88.
LIRIODENDRON, 64.
LOCUST, 165, 169.
LOCUST, CLAMMY 169.
MAACKIA, 171.
M.ACLURA, 56.
MADDENIA, 143.
MALLBNIA, 143.
MAGNOLIA, 5, 65.
MAIDENHAIR-TREE, 31.
MALUS, 58, 100, 138.
MAPLE, 37, 39, 46, 47, 150, 155.
MEDLAR, 61, 137.
MESPILUS, 61, 137.
MORUS, 67.
MOUNTAIN-ASH, 97, 131, 176.
MOUNTAIN LAUREL, 11.
MULBERRY, 67.
MYRPCA. 8, 10.
NANNY- BERRY, 40.
NYSSA. 85.
OAK. 80. 96, 127.
OLEASTER, 52.
38
OSAGE ORANGE, 56.
OSMANTHUS, 4.
OSTRYA, 147.
OXYDENDRUM, 129.
PAGODA-TREE, JAPAN, 171.
PALIURUS, 55.
PAPAW, 69.
PAPER MULBERRY, 67.
PARROTIA, 110.
PARROTIOPSrS, 110.
PAULOWNIA, 49.
PEA-TREE, 163.
PEACH, 136.
PEAR, 61, n, 85, 100, 138.
PECAN, 179.
PEPPERIDGE, 85.
PERSEA, 11.
PERSIMMON, 82.
PHELLODENDRON, 158.
PHOTINIA, 140.
PICEA, 16.
PINE, 13.
PINUS, 13.
PLATANUS, 63.
PLATYCARYA, 177.
PLUM, 60, 144.
PLUM-YEW, 20.
PONCIRUS, 152.
POPLAR, 89, 115.
POPULUS, 89, 115.
PORTUGAL LAUREL, 8.
PRICKLY ASH, 165.
PRIDE OF INDIA 172, 183.
PRUNUS, 8, 60, 99, 135, 136, 144.
PSEUDOLARIX, 33.
PSEUDOTSUGA, 21.
PTELEA, 152.
PTEROCARYA, 179.
PTEROCELTIS, 104.
PTEROSTYRAX, 111.
PYRUS, 58, 61, n, 85, 100. 138.
QUERCUS, 80, 96, 127.
QUINCE, 83.
RAISIN-TREE, JAPANESE 103
RED BAY, 11.
REDBUD, 72.
RED CEDAR, 26.
RED OAK group, 96.
RETINISPORA, 28.
RETINOSPORA, 28.
RHAMNUS, 41, 78, 113.
RHODODENDRON, 9, 80. RHUS, 170, 174. ROBINIA, 165, 168. SALIX, 78, 114. SAMBUCUS, 160. SASSAFRAS, 75, 90. SCIADOPITYS, 13. SEA-BUCKTHORN, 52. SEQUOIA, 23. SHADBUSH, 131. SHEEP-BERRY, 40. 9HEPHERDIA, 42. SHINGLE OAK, 80. SHRUBBY ALTHEA, 89. SILK-TREE, 180. SILVERBELL-TREE, 128. SINOWILSONIA, 108. SMOKE-TREE, AMERICAN, 66. SNOWDROP-TREE, 128. SOPHORA, 171.
SORIBUS, 97, 131, 176. SORREL-TREE, 129. SOUR GUM, 85. 90URWOOD, 129. SPICE-BUSH, 12, 75, 87. SPINDLE-TREE, 41.
SPRUCE, 16.
STAPHYLEA, 150.
STEWARTIA, 118.
STORAX, 112. STYRAX, 112.
SUGAR- BERRY, 104, 124.
SUMAC, 170, 174.
SWAMP PRIVET, 38.
SWEET GUM, 88.
SWEET-LEAF, 129.
SYCAMORE, 63.
SYMPLOOOS, 129.
SYRINGA, 45.
TAMARACK, 33.
TAMARISK, 31.
TAMARIX, 31.
TAXODIUM, 32.
TAXUS 19. ' TETRACENTRON, 102.
THUJA, 29.
THUJOPSrS, 28.
TILIA, 94, 126.
TORREYA, 20.
TREE OF HEAVEN, 167.
TSUGA, 17.
39
TUPELO, 85. ULMUS, 147. UMBRELLA PINE, 13. VARNISH-TREE, 172, 183. VIBURNUM, 40. WALNUT, 170, 178. WALNUT, ENGLISH, 170. WAX-iMYRTLE, 8, 10. WHITE ALDER, 120. WHITE BEAM-TREE, 131. WHITE CEDAR, 26, 29. WHITE OAK group, 96. WHITE POPLAR, 89.
WHITEWOOD, 94, 126. WILD CAMELLIA, 118. WILLOW, 78, 114. WILLOW OAK, 80. WING-NUT, 179. WINTER HAZEL, 122. WITCH HAZEL, 108. XANTHOCEROS, 176. YELLOW-WOOD, 166. YEW, 19.
ZANTHOXYLUM, 165. ZELKOVA, 146. ZIZYPHUS, 55.
40
TUPELO, 85. ULMUS, 147. UMBRELLA PPNE, 13. VARNISH-TREE, 172, | VIBURNUM, 40. WALNUT, 170, 178. WALNUT, ENGLISH, | WAX-MYRTLE, 8, 10. WHITE ALDER, 120. WHITE BEAM-TREEJ WHITE CEDAR, 26, WHITE OAK group, WHITE POPLAR, 89.
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