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.

Bark: Smooth and pale brown at first, becoming darker and furrowed when old.