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_