Part 2

Leaves needle-like or scale-like, often evergreen.

1. Leaves in clusters of 2 or more. 2. Leaves in clusters of 10 or more, falling off during autumn. 3. Leaves blue-green; cone-scales smooth Larix laricina 3. Leaves bright green; cone-scales hairy Larix decidua 2. Leaves in clusters of 2-5, evergreen. 4. Leaves in clusters of 5 Pinus strobus 4. Leaves in clusters of 2-3. 5. Leaves in clusters of 2. 6. Most or all the leaves less than 3 inches long, usually twisted. 7. Leaves up to 1½ inches long; sheath at base of leaves not longer than ⅛ inch Pinus banksiana 7. Leaves 2-3 inches long; sheath at base of leaves at least ⅓ inch long Pinus sylvestris 6. Most or all the leaves longer than 3 inches, rarely twisted. 8. Leaves mostly less than 5 inches long; cone-scale with a small spine Pinus echinata 8. Leaves mostly more than 5 inches long; cone-scale without a spine Pinus resinosa 5. Leaves in clusters of 3. 9. Leaves flexible, mostly less than 5 inches long; sheath at base of leaves about ¼ inch long Pinus echinata 9. Leaves stiff, mostly more than 5 inches long; sheath at base of leaves about 1 inch long Pinus taeda 1. Leaves solitary. 10. Leaves evergreen, of 2 types, some of them scale-like and about ⅛ inch long, some of them needle-like and up to ⅓ inch long Juniperus virginiana 10. Leaves falling off in autumn, all needle-like, usually at least ½ inch long. 11. Leaves 3-angled. 12. Leaves blue-green Larix laricina 12. Leaves bright green Larix decidua 11. Leaves flat Taxodium distichum

GROUP B

Leaves broad and flat, never needle-like or scale-like, compound.

1. Leaves alternate. 2. Leaflets 3 Ptelea trifoliata 2. Leaflets 5 or more. 3. Main stalk between leaflets winged on either side Rhus copallina 3. Main stalk between leaflets not winged. 4. Leaves with an even number of leaflets, often doubly compound. 5. Leaflets not more than ½ inch wide. 6. Pods usually 12 inches long or longer, with 6 or more seeds Gleditsia triacanthos 6. Pods 1-2 inches long, with 1-3 seeds Gleditsia aquatica 5. Some or all the leaflets at least one inch broad. 7. Leaves doubly compound; leaflets smooth along the edges; leaves without a foul odor when crushed Gymnocladus dioicus 7. Leaves once compound; leaflets usually with a few coarse teeth along the edges; leaves with a foul odor when crushed Ailanthus altissima 4. Leaves with an odd number of leaflets, once compound (twice compound in Aralia spinosa, which has prickly leafstalks). 8. Leaflets without teeth along the edges. 9. Leaflets less than 1 inch broad and 2 inches long; twigs with short spines at base of leaf stalks Robinia pseudoacacia 9. Leaflets up to 4 inches long and up to 2 inches broad; twigs without spines. 10. Some or all the leaflets alternate; base of leafstalk conspicuously swollen Cladrastis lutea 10. All the leaflets opposite; base of leafstalk not swollen Rhus vernix 8. Leaflets toothed along the edges. 11. Leaves doubly compound, often with small prickles on the leafstalks and on some of the veins Aralia spinosa 11. Leaves once compound, without prickles. 12. All leaves with 11 or more leaflets. 13. Leafstalks and lower surface of leaves completely smooth Rhus glabra 13. Leafstalks and lower surface of leaves (at least on the veins) hairy. 14. Pith of twigs chambered when cut lengthwise. 15. Pith pale brown; bark dark brown, with roughened ridges Juglans nigra 15. Pith dark brown; bark gray, with smooth ridges Juglans cinerea 14. Pith of twigs solid. 16. Leaves strongly aromatic when crushed; twigs not covered with velvety hairs. 17. Bud scales with yellow hairs; nut 1½ to 2 times longer than broad Carya illinoensis 17. Bud scales without yellow hairs; nut about as broad as long Carya aquatica 16. Leaves not aromatic when crushed; twigs covered with velvety hairs Rhus typhina 12. Some or all leaves with less than 11 leaflets. 18. Buds with 4-6 scales arranged in pairs; most of the leaves with at least 9 leaflets. 19. Terminal leaflet without a stalk or with a very short stalk; buds mustard-yellow Carya cordiformis 19. Terminal leaflet with a well-developed stalk; bud reddish-brown Carya aquatica 18. Buds with 6 or more overlapping scales; most of the leaves with fewer than 9 leaflets (except sometimes in Carya tomentosa and Carya laciniosa), never with 11 leaflets. 20. Teeth along the leaf margin with small tufts of hairs Carya ovata 20. Teeth along the leaf margin without small tufts of hairs. 21. Lower surface of leaflets densely and uniformly hairy. 22. Stalk to which leaflets are attached densely hairy; bark tight, not shaggy Carya tomentosa 22. Stalk to which leaflets are attached smooth or sparsely hairy; bark shaggy at maturity Carya laciniosa 21. Lower leaf surface smooth, or with tufts of hairs in the vein axils, or sometimes sparsely hairy along the veins. 23. Scales of buds, stalk of leaves, and young twigs rusty-hairy or -scaly Carya texana 23. Rusty hairs and scales not present. 24. Leaflets mostly 5; bud scales without hairs at the tip; bark tight, not peeling Carya glabra 24. Leaflets mostly 7; bud scales with hairs at the tip; bark peeling at maturity Carya ovalis 1. Leaves opposite. 25. Leaves palmately compound. 26. Leaflets mostly 7; buds very sticky Aesculus hippocastanum 26. Leaflets mostly 5; buds not sticky. 27. Fruit prickly; flowers yellow Aesculus glabra 27. Fruit smooth; flowers red Aesculus discolor 25. Leaves pinnately compound, or sometimes with only 3 leaflets. 28. Leaflets usually 3, or sometimes 5; twigs green or glaucous Acer negundo 28. Leaflets usually 7 or more, sometimes 5; twigs not green. 29. Some or all of the twigs square Fraxinus quadrangulata 29. Stems not square. 30. Leaflets without stalks Fraxinus nigra 30. Leaflets stalked. 31. Stalks of the leaflets winged. Fraxinus pennsylvanica var. subintegerrima 31. Twigs and leafstalks smooth 32. Leaflets whitened on the lower surface Fraxinus americana 32. Leaflets green or yellow-brown on the lower surface Fraxinus tomentosa

GROUP C

Leaves broad and flat, never needle-like or scale-like, simple, opposite or whorled.

1. Leaves (or some of them) in whorls of 3. 2. Leaves with a bad odor when crushed; flowers with conspicuous purple spots Catalpa bignonioides 2. Leaves without a bad odor when crushed; flowers merely lined with purple Catalpa speciosa 1. Leaves opposite. 3. Leaves at least 6 inches long and 6 inches broad, heart-shaped at the base, never palmately lobed Paulownia tomentosa 3. Leaves usually less than 6 inches long and 6 inches broad, not heart-shaped at the base or, if slightly heart-shaped, then also palmately lobed. 4. Leaves palmately lobed. 5. Leafstalk with milky sap when broken Acer platanoides 5. Leafstalk without milky sap. 6. Areas between leaf lobes mostly V-shaped; leaves usually silvery or white on the lower surface. 7. Leaves deeply divided, the areas between the lobes extending more than half-way to the midvein Acer saccharinum 7. Leaves shallowly divided, the areas between the lobes extending less than half-way to the midvein. 8. Leaves completely covered with a white felt on the lower surface Acer rubrum var. drummondii 8. Leaves smooth or sparsely hairy on the lower leaf surface Acer rubrum 6. Areas between leaf lobes mostly U-shaped; leaves green or paler on the lower surface, not white or silvery. 9. Leaves with the edges drooping. 10. Leaves green on the lower surface; small leafy outgrowths sometimes present at the base of the leafstalk Acer nigrum 10. Leaves grayish on the lower surface; small leafy outgrowths at the base of the leafstalk absent Acer barbatum 9. Leaves flat, the edges not drooping Acer saccharum

4. Leaves not lobed. 11. Leaves toothed along the edges. 12. Edges of leaves regularly toothed from tip of leaf to base; leaves usually short-pointed or rounded at the tip. 13. Buds, leafstalks, and veins on the lower surface of the leaf covered with rusty hairs Viburnum rufidulum 13. Buds, leafstalks, and veins on the lower surface of the leaf without rusty hairs. 14. Leaf stalks wavy along the edges Viburnum lentago 14. Leaf stalks not wavy along the edges. 15. Branches spine-tipped Rhamnus cathartica 15. Branches not spine-tipped Viburnum prunifolium 12. Edges of leaves toothed only above the middle of the leaf; leaves tapering to a long point Forestiera acuminata 11. Leaves not toothed along the edges. 16. Upper surface of leaves rough to the touch Cornus drummondii 16. Upper surface of leaves smooth. 17. Leaves with deeply impressed veins on the upper surface; lower surface of leaves gray or whitish. 18. Leaves often nearly as broad as long; flowers surrounded by 4 large, white bracts; berries red; twigs green Cornus florida 18. Leaves longer than broad; flowers not surrounded by 4 large, white bracts; berries white; twigs gray Cornus racemosa 17. Leaves without deeply impressed veins; leaves often paler on the lower surface, but not gray or whitish Forestiera acuminata

GROUP D

Leaves broad and flat, never needle-like or scale-like, simple, alternate, neither toothed nor lobed.

1. Most or all of the leaves more than six inches long. 2. Leaves long-tapering to the base; winter buds elongated, about ⅛ inch long, covered with reddish-brown hairs Asimina triloba 2. Leaves rounded or only short-tapering to the base; winter buds either ½ inch long and white-hairy, or rounded and yellow. 3. Leafstalks usually more than 1½ inches long, hairy; buds nearly round, yellow Nyssa aquatica 3. Leafstalks usually less than 1½ inches long, smooth; buds elongated, white-hairy Magnolia acuminata 1. Most or all of the leaves less than six inches long. 4. Leafstalks with milky sap; twigs usually bearing small spines near the point of the leaf attachment Maclura pomifera 4. Leafstalks without milky sap; twigs not spiny. 5. Leaves spicy-aromatic when crushed, twigs green Sassafras albidum 5. Leaves not spicy-aromatic when crushed; twigs usually not green. 6. Leaves distinctly asymmetrical at base, usually obviously 3-nerved from the base. 7. Leaves usually at least twice longer than broad, rounded at the base Celtis laevigata 7. Leaves usually less than twice longer than broad, more or less heart-shaped at the base Celtis tenuifolia 6. Leaves symmetrical at the base, with a single main vein. 8. Leaves heart-shaped at the base, about as broad as long Cercis canadensis 8. Leaves rounded or tapering to the base, longer than broad. 9. Many of the leaves clustered near the tips of the twigs. 10. Leaves abruptly short-pointed at the tip Nyssa sylvatica 10. Leaves tapering to the tip. 11. Veins of leaf deeply impressed, strongly arching toward the tip of the leaf; fruit a berry Cornus alternifolia 11. Veins of leaf not deeply impressed nor strongly arching toward the tip of the leaf; fruit an acorn. 12. Lower surface of leaves hairy; leafstalk usually hairy; leaves usually one inch wide or wider Quercus imbricaria 12. Lower surface of leaves smooth except for the veins; leafstalk usually smooth; leaves usually less than one inch wide Quercus phellos 9. Leaves not clustered near the tips of the twigs. 13. Leaves usually with 10 or more pairs of veins; leafstalks often 1½ inches long or longer Nyssa aquatica 13. Leaves usually with 6-8 pairs of veins; leafstalks rarely as long as 1½ inches. 14. Leaves abruptly contracted to a short point at the tip. 15. Leaves usually about twice as long as broad; fruit an orange berry about 1 inch in diameter Diospyros virginiana 15. Leaves usually less than twice as long as broad; fruit a blue berry up to ½ inch in diameter Nyssa sylvatica 14. Leaves gradually tapering to the tip Rhamnus caroliniana

GROUP E

Leaves broad and flat, never needle-like or scale-like; leaves simple, alternate, toothed but not lobed.

1. Leaves asymmetrical at the base. 2. Leaves with 3 main veins arising from the base of the blade. 3. Edge of leaf with low, rounded teeth or merely wavy Hamamelis virginiana 3. Edge of leaf sharply or finely toothed. 4. Most of all the leafstalks less than one inch long; trunk usually warty. 5. Upper surface of leaf very rough to the touch; leaves thick and leathery. 6. Leaves tapering to a long point at the tip; most or all of the blades 3 inches long or longer Celtis occidentalis 6. Leaves tapering to a short point at the tip; most or all of the blades less than 3 inches long Celtis tenuifolia 5. Upper surface of leaf smooth or only slightly rough to the touch; leaves thin and membranaceous. 7. Leaves at least three times longer than broad Celtis laevigata 7. Leaves less than three times longer than broad. 8. Some or all the leaves 3 inches long or longer Celtis occidentalis 8. Leaves less than 3 inches long Celtis tenuifolia 4. Leafstalks more than 1 inch long. 9. Leaves smooth on the lower surface except for small tufts of hairs where the veins meet Tilia americana 9. Leaves hairy on the lower surface. 10. Lower surface of leaves white Tilia heterophylla 10. Lower surface of leaves green Tilia americana

2. Leaves with one main vein arising from the base of the blade. 11. Some of the twigs with corky wings. 12. Some or all the leaves four inches long or longer; leaf-stalks more than ⅛ inch long Ulmus thomasii 12. None of the leaves four inches long; leafstalks up to ⅛ inch long Ulmus alata 11. Twigs without corky wings. 13. Leaves very rough-hairy to the touch Ulmus rubra 13. Leaves smooth or soft to the touch. 14. Edge of leaf doubly toothed (each tooth divided into a second small tooth). 15. Leaves distinctly one-sided at the base; leafstalks often smooth Ulmus americana 15. Leaves only slightly one-sided at the base; leafstalks hairy. 16. Bark of trunk with sinewy ridges; fruit enclosed in flat, 3-lobed bracts; lower lateral veins of leaf unbranched Carpinus caroliniana 16. Bark of trunk broken into scales; fruit surrounded by inflated, bladdery bracts; lower lateral veins of leaf branched Ostrya virginiana 14. Edge of leaf singly toothed. 17. Leaves smooth on the lower surface; leafstalks smooth Ulmus pumila 17. Leaves hairy on the lower surface, at least where the veins meet; leafstalks usually hairy Planera aquatica 1. Leaves symmetrical at the base. 18. Leaves with 2-4 irregular teeth along the edges. 19. Leaves usually with 10 or more pairs of veins; leaf stalks often 1½ inches long or longer Nyssa aquatica 19. Leaves usually with 6-8 pairs of veins; leaf stalks rarely as long as 1½ inches Nyssa sylvatica 18. Leaves more regularly toothed with more than 4 teeth along the edges. 20. Leafstalks with milky sap when broken. 21. Leaf stalks and lower surface of leaf with long hairs Broussonetia papyrifera 21. Leaf stalks and lower surface of leaf smooth or with short hairs. 22. Lower leaf surface hairy between the veins Morus rubra 22. Lower leaf surface smooth or hairy only on the veins Morus alba 20. Leafstalks without milky sap when broken. 23. Leaves at least 4 times as long as broad. 24. Leafstalks less than ⅛ inch long; leaves irregularly toothed along the edges Salix interior 24. Leafstalks more than ⅛ inch long; leaves regularly toothed along the edges. 25. Leaves green on the lower surface Salix nigra 25. Leaves whitish on the lower surface. 26. Each leaf with a pair of leaf-like stipules at the base of the leafstalk Salix caroliniana 26. Each leaf without a pair of leaf-like stipules Salix amygdaloides 23. Leaves less than 4 times as long as broad. 27. Leaves as broad as long or broader. 28. Leaf stalks not flattened. 29. Leaves strongly whitened on the lower surface, not heart-shaped at the base Populus alba 29. Leaves not strongly whitened on the lower leaf surface, heart-shaped at the base Populus heterophylla 28. Leaf stalks flattened. 30. Leaves basically triangular in shape, coarsely toothed Populus deltoides 30. Leaves basically ovate or spherical, coarsely or finely toothed. 31. Leaves with 20 or more fine teeth along the edges Populus tremuloides 31. Leaves with up to 15 coarse teeth along the edges. Populus grandidentata 27. Leaves longer than broad. 32. Twigs usually with sharp spines. 33. Leaves broadest below the middle; fruit a small apple. 34. Many of the leaves narrowly oblong to narrowly elliptic Malus angustifolia 34. Most of the leaves ovate to oval to broadly lance-shaped. 35. Twigs and young leaves densely hairy Malus ioensis 35. Twigs and young leaves smooth or nearly so Malus coronaria 33. Leaves broadest at or above the middle; fruit a hawthorn. 36. Leaves broadest at the middle; leafstalks one inch long or longer Crataegus viridis 36. Leaves broadest above the middle; leafstalks up to ¾ inch long. 37. Leaves leathery, smooth on both surfaces Crataegus crus-galli 37. Leaves not leathery, usually somewhat hairy on the lower surface Crataegus punctata 32. Twigs not spiny. 38. Some of the twigs with corky wings. 39. Some or all the leaves 4 inches long or longer; leafstalks more than ⅛ inch long Ulmus thomasii 39. None of the leaves 4 inches long; leafstalks up to ⅛ inch long Ulmus alata 38. None of the twigs with corky wings. 40. Individual teeth along edge of the leaf at least ¼ inch long. 41. Most of the veins not reaching to the tip of each leaf; lower surface of leaf usually silvery-white Quercus bicolor 41. Most of the veins projecting to the tip of each leaf; lower surface of leaf green or pale, but usually not silvery-white. 42. Leaves usually with sharp-pointed teeth. 43. Fruit an acorn; lower leaf surface usually covered with very short hairs Quercus muhlenbergii 43. Fruit enclosed in a prickly bur; lower leaf surface smooth or nearly so Castanea dentata 42. Leaves usually with somewhat rounded teeth. 44. Cup of acorn at least 1 inch across; trunk whitish to gray Quercus michauxii 44. Cup of acorn less than 1 inch across; trunk brown to black Quercus prinus 40. Individual teeth along edge of leaf up to ⅛ inch long. 45. Some of the leaves produced from short, stubby shoots along the main twigs Ilex decidua 45. Twigs without short, stubby side shoots. 46. Leafstalks with 1 or more small glands (“bumps”), usually near the point of attachment to the blade. 47. Each tooth along the edge of the leaf bearing a small, reddish-brown gland. 48. Some or all leaves one inch broad or broader. 49. Leaves flat Prunus hortulana 49. Leaves more or less folded down the middle Prunus munsoniana 48. None of the leaves as much as one inch broad Prunus angustifolia 47. Teeth along the edge of the leaf not bearing a gland. 50. Leaves usually with a dull, wrinkled surface; fruit a plum Prunus americana 50. Leaves usually appearing smooth and rather shiny; fruit an elongated cluster of small cherries. 51. Teeth along edge of leaf curving inward, usually rather blunt Prunus serotina 51. Teeth along edge of leaf pointing outward, usually sharp-pointed Prunus virginiana 46. Leafstalks not bearing glands. 52. Leaves doubly toothed along the edges. 53. Bark peeling off into papery strips or layers; leaves usually about two-thirds as broad as long or broader. 54. Bark yellowish, silvery-gray, or creamy-white. 55. Bark yellowish or silvery-gray; leaves with 8 or more pairs of veins Betula lutea 55. Bark creamy-white; leaves with no more than 7 pairs of veins Betula papyrifera 54. Bark reddish-brown Betula nigra 53. Bark broken into small plates, or smooth and sinewy, not peeling off into papery strips or layers. 56. Bark of trunk with sinewy ridges; fruit enclosed in flat, 3-lobed bracts; lower lateral veins of leaf unbranched Carpinus caroliniana 56. Bark of trunk broken into scales; fruit enclosed in inflated, bladdery bracts; lower lateral veins of leaf branched Ostrya virginiana 52. Leaves singly toothed along the edges. 57. Leaves heart-shaped at the base. 58. Leaves up to six inches long and nearly as broad Populus heterophylla 58. Leaves not more than four inches long and about half as broad. 59. Leaves bronze as they unfold; leafstalk smooth Amelanchier laevis 59. Leaves densely white-hairy as they unfold; leafstalk somewhat hairy Amelanchier arborea 57. Leaves rounded or tapering to the base, not heart-shaped. 60. Teeth along edge of leaf widely spaced, at least ¼ inch apart Fagus grandifolia 60. Teeth along edge of leaf closely and regularly spaced. 61. Leafstalk hairy; fruit fleshy. 62. Leaves shiny on the upper surface; leafstalks ½ inch long or longer Rhamnus caroliniana 62. Leaves dull on the upper surface; leafstalks up to ¼ inch long Planera aquatica 61. Leafstalk smooth at maturity; fruit dry and variously winged. 63. Some of the leaves three inches long or longer; fruit 4-winged or a woody “cone.” 64. Leaves pointed at the tip; fruit 4-winged Halesia carolina 64. Leaves rounded at the tip; fruit a woody “cone” Alnus glutinosa 63. Leaves less than 3 inches long; fruit surrounded by a flat wing Ulmus pumila

GROUP F

Leaves broad and flat, never needle-like or scale-like; leaves simple, alternate, lobed.

1. Leafstalks with milky sap when broken. 2. Leafstalks and lower surface of leaf with long hairs Broussonetia papyrifera 2. Leafstalks and lower surface of leaf smooth or with short hairs. 3. Lower leaf surface hairy between the veins Morus rubra 3. Lower leaf surface smooth or hairy only on the veins Morus alba 1. Leafstalks without milky sap when broken. 4. Twigs usually with sharp spines. 5. Leaves broadest at the middle or above the middle. 6. Leaves broadest at the middle; lower surface of leaf smooth except for a few tufts of hairs near the veins Crataegus viridis 6. Leaves broadest above the middle; lower surface of leaf hairy throughout Crataegus punctata 5. Leaves broadest below the middle. 7. Leaves hairy throughout on the lower surface. 8. Leaves mostly tapering to the base; fruit a crab apple Malus ioensis 8. Leaves rounded at the base; fruit a hawthorn. 9. Fruit with pitted seeds; flowers appearing in late May and June Crataegus calpodendron 9. Fruit without pitted seeds; flowers appearing in April or early May Crataegus mollis 7. Leaves smooth on the lower surface or hairy only on the veins. 10. Leaves tapering to the base. 11. Leaves oval to ovate to broadly lance-shaped Malus coronaria 11. Leaves narrowly oblong to narrowly elliptic Malus angustifolia 10. Leaves rounded at the base. 12. Leaves blue-green; fruit spherical or nearly so Crataegus pruinosa 12. Leaves green; fruit shaped like a little apple Malus coronaria 4. Twigs without spines. 13. Leaves star-shaped Liquidambar styraciflua 13. Leaves not star-shaped. 14. Leaves 4-lobed, smooth on both surfaces Liriodendron tulipifera 14. Leaves more than 4-lobed, hairy on one or both surfaces. 15. Leaves palmately lobed and veined. 16. Leaves densely coated with white felt on the lower surface Populus alba 16. Leaves without a coat of white felt on the lower surface Platanus occidentalis 15. Leaves pinnately lobed and veined. 17. Lobes of leaf with bristle-tips. 18. Leaves broadest above the middle Quercus marilandica 18. Leaves broadest at or below the middle. 19. Leaves hairy throughout on the lower surface. 20. Lower surface of leaves with gray hairs; base of leaf blade usually broadly rounded. 21. Leaves with 5-11 more or less equal lobes, the uppermost lobe not strongly curved Quercus pagodaefolia 21. Leaves with 3-5 more or less unequal lobes, the uppermost lobes often strongly curved Quercus falcata 20. Lower surface of leaves with rusty hairs; base of leaf blade not broadly rounded Quercus velutina 19. Leaves smooth on the lower surface or hairy only next to the veins. 22. Leaves divided less than halfway to the middle. 23. Leafstalks hairy; buds hairy, gray Quercus velutina 23. Leafstalks smooth; buds smooth, reddish-brown Quercus rubra 22. Leaves divided more than halfway to the middle. 24. Leafstalks hairy; cup of acorn fringed around the edge Quercus velutina 24. Leafstalks smooth; cup of acorn not fringed around the edge. 25. Lower surface of leaves with large tufts of hairs in the vein axils. 26. Cup of acorn saucer-shaped. 27. Cup of acorn up to ½ inch broad. Quercus palustris 27. Cup of acorn more than ½ inch broad Quercus shumardii 26. Cup of acorn top-shaped. 28. Cup of acorn enclosing about ⅓ the nut at most Quercus shumardii 28. Cup of acorn enclosing more than one-third of the nut Quercus ellipsoidalis 25. Lower surface of leaves smooth or with small tufts in hairs in the vein axils Quercus coccinea 17. Lobes of leaf with round tips, not bristle-tipped. 29. Leaves smooth on the lower surface Quercus alba 29. Leaves hairy on the lower surface. 30. Upper three lobes of leaf squarish, forming a cross; twigs hairy Quercus stellata 30. Leaves without three squarish lobes at the upper end; twigs smooth or nearly so. 31. Edge of acorn cup with a fringe Quercus macrocarpa 31. Edge of acorn cup not fringed Quercus lyrata

Key to Illinois Trees in Winter

1. Green leaves present during winter, needle-like or scale-like Group G 1. Green leaves absent during winter Group H

GROUP G

1. Leaves in clusters of 2 or more. 2. Leaves in clusters of 5 Pinus strobus 2. Leaves in clusters of 2-3. 3. Leaves in clusters of 2. 4. Most or all the leaves less than 3 inches long, usually twisted. 5. Leaves up to 1½ inches long; sheath at base of leaves not longer than ⅛ inch Pinus banksiana 5. Leaves 2-3 inches long; sheath at base of leaves at least ⅓ inch long Pinus sylvestris 4. Most or all the leaves longer than 3 inches, rarely twisted. 6. Leaves mostly less than 5 inches long; cone-scale with a small spine Pinus echinata 6. Leaves mostly more than 5 inches long; cone-scale without a spine Pinus resinosa 3. Leaves in clusters of 3. 7. Leaves flexible, mostly less than 5 inches long; sheath at base of leaves about ¼ inch long Pinus echinata 7. Leaves stiff, mostly more than 5 inches long; sheath at base of leaves about 1 inch long Pinus taeda 1. Leaves solitary, of 2 types, some of them scale-like and about ⅛ inch long, some of them needle-like and up to ⅓ inch long Juniperus virginiana

GROUP H

1. Leaf scars absent (scars which resemble leaf scars present but lacking bundle scars) Taxodium distichum 1. Leaf scars present. 2. Leaf scars in whorls of 3 Catalpa spp. 2. Leaf scars opposite or alternate. 3. Leaf scars opposite. 4. Bundle scar 1 Forestiera acuminata 4. Bundle scars 3 or more. 5. Bundle scars usually 9 or more. 6. Pith hollow or sometimes chambered Paulownia tomentosa 6. Pith solid, not chambered. 7. Twigs 4-sided Fraxinus quadrangulata 7. Twigs not 4-sided. 8. Twigs hairy. 9. Leaf scars notched at top. 10. Twigs with conspicuous large lenticels; trunks swollen at the base Fraxinus tomentosa 10. Twigs with inconspicuous lenticels; trunks not swollen at the base Fraxinus americana 9. Leaf scars more or less straight across at the top Fraxinus pennsylvanica 8. Twigs smooth. 11. Leaf scars oval; buds brownish-black to black Fraxinus nigra 11. Leaf scars half-round; buds brown. 12. Leaf scars notched at the top Fraxinus americana 12. Leaf scars more or less straight across the top Fraxinus pennsylvanica var. subintegerrima 5. Bundle scars usually 3-7 (sometimes 9 in Acer negundo). 13. Leaf scars very broad, usually at least ⅓ inch across. 14. Bark smooth Aesculus discolor 14. Bark becoming furrowed and scaly Aesculus glabra 13. Leaf scars narrow, less than ⅓ inch across. 15. Buds with 2 exposed outer scales. 16. Twigs gray or gray-brown. 17. Buds long and narrow, at least 5 times longer than broad Viburnum lentago 17. Buds shorter, at most 3 times longer than broad. 18. Buds reddish-brown. 19. Buds smooth or scurfy Viburnum prunifolium 19. Buds hairy Viburnum rufidulum 18. Buds light brown. 20. Buds hairy Cornus drummondii 20. Buds smooth or nearly so Cornus racemosa 16. Twigs purple or orange-brown. 21. Twigs purplish Cornus florida 21. Twigs orange-brown, at least usually not purplish Cornus racemosa 15. Buds with more than 2 exposed scales. 22. Twigs green or glaucous Acer negundo 22. Twigs brown. 23. Buds rounded, several in a cluster; twigs red or orange. 24. Twigs hairy Acer rubrum var. drummondii 24. Twigs smooth. 25. Twigs with an unpleasant odor; bark scaly Acer saccharinum 25. Twigs without an unpleasant odor; bark not scaly Acer rubrum 23. Buds elongated; twigs brown or gray. 26. Ends of some twigs tapering to a spine Rhamnus cathartica 26. Ends of twigs not spiny. 27. Twigs (at least by the time they are 2 years old) pale gray-brown, dull Acer nigrum 27. Twigs pale reddish-brown, shiny. 28. Buds pointed at the tip Acer saccharum 28. Buds more or less rounded at the tip Acer barbatum 3. Leaf scars alternate. 29. Thorns or spines present. 30. Spines in pairs Robinia pseudoacacia 30. Spines solitary, although sometimes branched. 31. Spines scattered all along the twigs and branches Aralia spinosa 31. Spines not scattered all along the twigs and branches. 32. Thorns branched Gleditsia spp. 32. Thorns unbranched. 33. Buds pointed at the tip. 34. Twigs usually hairy Malus ioensis 34. Twigs usually smooth. 35. Buds with reddish scales Malus coronaria 35. Buds with chestnut-brown scales Malus angustifolia 33. Buds more or less rounded at the tip. 36. Terminal bud absent Maclura pomifera 36. Terminal bud present Crataegus spp. 29. Thorns or spines absent. 37. Pith chambered, at least at the nodes. 38. Leaf scars 3-lobed and usually with 3 groups of bundle scars. 39. Pith pale brown; leaf scars without velvety hairs at the top Juglans nigra 39. Pith chocolate-brown; leaf scars with velvety hairs at the top Juglans cinerea 38. Leaf scars half-round, not 3-lobed. 40. Pith chambered only at the nodes; stipular scars present. 41. Buds about ¼ inch long Celtis occidentalis 41. Buds about ⅛ inch long. 42. Twigs usually smooth; trees Celtis laevigata 42. Twigs usually hairy; shrubs Celtis tenuifolia 40. Pith chambered between the nodes as well as at most of the nodes; stipular scars absent. 43. Exposed bud scales 2 Diospyros virginiana 43. Exposed bud scales 4 Halesia carolina 37. Pith solid, although sometimes with diaphragms. 44. Pith with diaphragms. 45. Buds without bud scales Asimina triloba 45. Buds with 1 or more scales. 46. Bud scales 1-2; bundle scars 7 or more; stipular scars present. 47. Bud scale 1, hairy Magnolia acuminata 47. Bud scales 2, smooth Liriodendron tulipifera 46. Bud scales 3-several; bundle scars 3; stipular scars absent. 48. Buds about ¼ inch long Nyssa sylvatica 48. Buds up to 1 inch long Nyssa aquatica 44. Pith without diaphragms. 49. Bundle scar 1. 50. Twigs orange; bark reddish-brown Larix decidua 50. Twigs orange; bark reddish-brown Larix laricina 49. Bundle scars 2 or more. 51. Stipular scars forming a ring around the twig Platanus occidentalis 51. Stipular scars not forming a ring around the twig, or absent. 52. Twigs aromatic when cut. 53. Twigs green; buds generally smooth Sassafras albidum 53. Twigs orange-brown; buds generally hairy Betula lutea 52. Twigs not aromatic when cut. 54. Buds without scales. 55. Terminal buds larger than the rest of the buds. 56. Buds rusty-hairy or gray-woolly. 57. Buds rusty-hairy, 2-3 times longer than broad Asimina triloba 57. Buds gray-woolly, not much longer than broad Malus ioensis 56. Buds smooth or, if hairy, not conspicuously rusty-hairy or gray-woolly. 58. Leaf scars lobed; twigs without stipular scars. 59. Buds bright yellow Carya cordiformis 59. Buds brown or reddish-brown. 60. Terminal bud up to ½ inch long; twigs with orange lenticels Carya illinoensis 60. Terminal bud up to ¼ inch long; twigs with pale lenticels Carya aquatica 58. Leaf scars unlobed; twigs with stipular scars. 61. Buds pale brown; twigs often zig-zag Hamamelis virginiana 61. Buds light brown; twigs mostly straight Rhamnus caroliniana 55. Terminal buds smaller than other buds, or absent. 62. Pith reddish-brown; leaf scars often ½ inch across Gymnocladus dioicus 62. Pith not reddish-brown; leaf scars less than ½ inch across. 63. Milky sap present. 64. Twigs hairy. 65. Twigs velvety; pith yellow Rhus typhina 65. Twigs not velvety; pith whitish Rhus copallina 64. Twigs smooth Rhus glabra 63. Milky sap absent. 66. Leaf scars completely encircling the bud Cladrastis lutea 66. Leaf scars only partly encircling the bud Ptelea trifoliata 54. Buds with 1 or more scales. 67. Buds with 1 scale Salix spp. 67. Buds with 2 or more scales. 68. Bundle scar 1. 69. Twigs with short spur-like shoots Ilex decidua 69. Twigs without short spur-like shoots Diospyros virginiana 68. Bundle scars 2 or more. 70. Buds at least 4 times longer than broad. 71. Stipular scars encircling the twig, or nearly so Fagus grandifolia 71. Stipular scars not encircling the twigs, or absent. 72. Lowermost bud scale directly above the leaf scar Populus deltoides 72. Lowermost bud scale to one side of leaf scar. 73. Twigs reddish-brown, with pale lenticels Amelanchier arborea 73. Twigs gray-brown, with dark lenticels Amelanchier laevis 70. Buds less than 4 times longer than broad. (Go to 74) 74. Pith star-shaped, or triangular, or variously lobed in cross-section. 75. Lowermost bud scale directly above the leaf scar. 76. Twigs densely hairy; bark white Populus alba 76. Twigs smooth or sparsely hairy. 77. Visible bud scales more than 4. 78. Buds smooth, shiny, brown Populus tremuloides 78. Buds hairy, dull, gray Populus grandidentata 77. Visible bud scales 3-4. 79. Buds at least ½ inch long Populus deltoides 79. Buds less than ½ inch long Populus heterophylla 75. Lowermost bud scale to one side of leaf scar. 80. Buds clustered near the tip of the twig; bud scales in 5 rows. 81. Buds at least ¼ inch long. 82. Buds angular. 83. Buds smooth Quercus shumardii 83. Buds hairy, at least at tip. 84. Buds hairy all over. 85. Buds with rusty or brown hairs. 86. Buds with rusty hairs Quercus marilandica 86. Buds with brown hairs Quercus michauxii 85. Buds with gray hairs Quercus velutina 84. Buds hairy only at the tip. 87. Buds light red-brown Quercus pagodaefolia 87. Buds dark red-brown Quercus coccinea 82. Buds not angular. 88. Buds and twigs orange-brown Quercus prinus 88. Buds and twigs red, red-brown, dark brown, or gray-brown. 89. Buds red or red-brown. 90. Buds light red to light red-brown Quercus rubra 90. Buds dark red to dark red-brown Quercus falcata 89. Buds dark brown Quercus coccinea 81. Buds less than ¼ inch long. 91. Buds pointed at the tip. 92. Buds and twigs brown to orange-brown Quercus muhlenbergii 92. Buds and twigs red to red-brown to gray-brown. 93. Scales of buds hairy. 94. Twigs dark red-brown to gray; buds red-brown Quercus falcata 94. Twigs light or dark brown; buds gray-brown Quercus imbricaria 93. Scales of buds smooth or nearly so. 95. Buds dark red-brown Quercus phellos 95. Buds light red-brown Quercus palustris 91. Buds more or less rounded. 96. Twigs red-brown, shiny. 97. Buds not angular Quercus alba 97. Buds angular Quercus ellipsoidalis 96. Twigs gray to yellow-brown to purplish, dull. 98. Twigs and buds smooth or nearly so. 99. Twigs purplish, with a whitish coating Quercus bicolor 99. Twigs gray to yellow-brown Quercus lyrata 98. Twigs and buds hairy. 100. Buds red-brown Quercus stellata 100. Buds gray to gray-brown Quercus macrocarpa 80. Buds not clustered near the tip of the twig; bud scales not in 5 rows. 101. Bundle scars in more than 3 groups; leaf scars lobed. 102. Visible bud scales 2. 103. Buds bright yellow Carya cordiformis 103. Bud scales brown or reddish-brown. 104. Terminal bud up to ½ inch long; twigs with orange lenticels Carya illinoensis 104. Terminal bud up to ¼ inch long; twigs with pale lenticels Carya aquatica 102. Visible bud scales more than 2. 105. Some or all the terminal buds ½ inch long or longer. 106. Outermost bud scales falling away early, revealing pale inner scales; bark not peeling Carya tomentosa 106. Outermost bud scales persistent; bark peeling. 107. Twigs orange-brown, with orange lenticels Carya laciniosa 107. Twigs dark brown or red-brown, with pale lenticels Carya ovata 105. Terminal buds usually less than ½ inch long. 108. Buds rusty-hairy, with silvery or yellow scales Carya texana 108. Buds smooth or only slightly hairy, without scales. 109. Bark smooth or furrowed, not scaly Carya glabra 109. Bark becoming scaly Carya ovalis 101. Bundle scars in 3 groups; leaf scars not lobed. 110. Buds up to ⅙ inch long; twigs bitter to the taste. 111. Pith triangular in cross-section Alnus glutinosa 111. Pith not triangular in cross section. 112. Buds very shiny Prunus serotina 112. Buds dull Prunus virginiana 110. Buds longer than ⅙ inch; twigs not bitter to the taste. 113. Twigs sometimes with corky wings; buds with 4 or more exposed scales Liquidambar styraciflua 113. Twigs without corky wings; buds with 2-3 exposed scales Castanea dentata 74. Pith round or nearly so in cross-section. 114. Terminal bud present. 115. Buds with 2-3 exposed scales Cornus alternifolia 115. Buds with 4 or more exposed scales. 116. Bud scales fleshy Crataegus spp.. 116. Bud scales not fleshy Prunus spp. 114. Terminal bud absent. 117. Leaf scars at least ½ inch across; bundle scars 9 Ailanthus altissima 117. Leaf scars smaller; bundle scars not 9. 118. Stipular scars absent. 119. Leaf scars bordered by hairs Cercis canadensis 119. Leaf scars not hairy Gleditsia spp. 118. Stipular scars present. 120. Exposed bud scales 2. 121. Milky sap present Broussonetia papyrifera 121. Milky sap absent. 122. Twigs gray or brown Tilia americana 122. Twigs light red Tilia heterophylla 120. Exposed bud scales 3 or more. 123. Exposed bud scales 3-4; lenticels horizontal. 124. Twigs with taste of wintergreen Betula lutea 124. Twigs without taste of wintergreen. 125. Twigs and buds smooth; bark white Betula papyrifera 125. Twigs and buds somewhat hairy; bark reddish Betula nigra 123. Exposed bud scales more than 4; lenticels more or less circular. 126. Bundle scars not in groups of 3; milky sap present. 127. Buds about ¼ inch long Morus rubra 127. Buds about ⅛ inch long Morus alba 126. Bundle scars in groups of 3; milky sap absent. 128. Exposed bud scales usually about 12 Carpinus caroliniana 128. Exposed bud scales usually about 6. 129. Leaf scars and bundle scars slightly elevated Ostrya virginiana 129. Leaf scars and bundle scars depressed. 130. Buds less than ⅛ inch long Ulmus pumila 130. Buds at least ⅛ inch long. 131. Some of the twigs with corky wings. 132. Buds about ¼ inch long Ulmus thomasii 132. Buds about ⅛ inch long Ulmus alata 131. None of the twigs with corky wings. 133. Buds rusty-hairy, about ¼ inch long Ulmus rubra 133. Buds light brown, smooth, about ⅛ inch long Ulmus americana

Trees of Illinois

SOUTHERN SUGAR MAPLE Acer barbatum Michx.

Growth Form: Medium tree up to 60 feet tall; trunk diameter up to 2 feet; crown rounded.