QK 482 B 27 1S31 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. i i 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 v^ t-/ A FIELD KEY TO The Genera of the Wild and Cultivated Hardy Trees of the Northeastern United States and Canada o: Z: ^1 — .- CD- Si i m • m ! m i '-^ i CD ; '-' □ m 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. ■th'~i V^' 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 U \ 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