2a Terminal buds 3/4 to 1 inch long and hairy...Magnolia grandiflora
2b Terminal buds shorter than 3/4 inch...3
3a Leaves with a thick, waxy cuticle...4
3b Leaves with only a slight, if any, apparent culticle...Ligustrum sinense
4a Leaf margins mostly entire...Quercus virginiana
4b Leaf margins various, not entire...5
5a Leaves with spiny tipped lobes...Ilex
opaca
5b Leaves with cuneate margins...Ilex vomitoria
6a Terminal buds longer than 3/4 inch,
with reddish brown scales...Populus
deltoides
6b Terminal buds shorter than 3/4 inch, or absent...7
7a Twigs with modified appendages...8
7b Twigs without appendages...15
8a Appendages thorns...10
8b Appendages corky ridges...9
9a Corky appendages flattened, winglike...Ulmus alata
9b Corky appendages in thickened ridges...Liquidambar styraciflua
10a Thorns branched, up to 3 inches long...Gleditsia triacanthos
10b Thorns less than 2 inches long...11
11a Thorns alternate, even spaced, in ones...12
11b Thorns opposite, or in bunches of 2 or more...13
12a Thorns about 1 inch long...Crataegus marshallii
12b Thorns shorter than 1 inch...14
13a Thorns bunched and along stem, twigs
green...Parkinsonia aculeata
13b Thorns in twos, buds small, blackish...Prosopis
glandulosa
14a Twigs glabrous, buds light red-brown, thorns 1/4 to 1 inch
long...Maclura pomifera
14b Small twigs pubescent, buds very small and variable in color...Crataegus spp.
(Most sources agree that Crataegus is impossible to key to
species with winter characters)
15a Bark with modified appendages...16
15b Bark without modified appendages...17
16a Bark appedages cone-shaped, with a small spine at the tip... Zanthoxylum clava-herculis
16b Bark appendages warty...Celtis laevigata
17a Bark peeling in thin, papery layers...Betula
nigra
17b Bark not papery...18
18a Fruits, or remnants thereof, remaining through winter...19
18b Fruit absent in winter...23
19a 3-lobed nut husk clinging; bud hairy and yellow-brown...Carya
illinoinensis
19b Fruit/remnant otherwise...20
20a Fruit bright red/red-orange berries...21
20b Fruit otherwise...22
21a Berries ovoid, bright red, in terminal clusters...Cornus florida
21b Berries spherical, orange red, clinging along twig, pea-sized...Ilex decidua
22a Fruits dried, reddish-black, in clusters of more than 50...Rhus copallina
22b Fruits in clusters of 6-10, round, black,
each with 3 white seeds...Sapium sebiferum
23a Terminal buds 1/4 inch long or longer, if terminal is absent,
lateral buds longer than 1/4 inch...24
23b Terminal/lateral buds shorter than 1/4 inch...33
24a Bud scales with some sort of pubescence...25
24b Bud scales glabrous or nearly so, or without scales...27
25a Terminal buds up to inch long...26
25b Terminal buds 1/4 to 5/16 inches long, with scurfy yellow
pubescence...Carya aquatica
26a Pubescence yellow-brown and scurfy...Carya illinoinensis
26b Pubescence red-brown and woolly...Quercus
marilandica
27a Buds distinctly globular, twigs bright
green...Cornus florida
27b Buds ovoid...28
28a Twig with chambered pith...Nyssa
sylvatica
28b Pith unchambered...29
29a Twig dark purplish-brown...30
29b Twig other than purplish-brown...31
30a Lateral buds as large as terminal buds, twig stout...Prunus umbellata
30b Lateral bud much smaller than terminal, twig slender...Prunus sp.
31a Twig red-brown...32
31b Twig covered with white and gray splotches...Quercus stellata
32a Twig stout (1/4 inch in diameter),
covered with raised, light brown lenticels...Pistacia
chinensis
32b Twig medium in length and slightly wrinkly, light brown...Tilia caroliniana
33a Bud scales with some sort of pubescence...34
33b Bud scales absent, or glabrous or nearly so, or buds so small as
for these characters to not be obvious...43
35a Leaf scar 1/4 inch across and long, bud globular, 1/8 inch
across...Melia azedrach
35b Leaf scar smaller than 1/4 inch...36
36a Bud dark brown with 2 pairs of
scales, white lenticels...Fraxinus texensis
36b Bud with only one set of scales...37
37a Pubescence yellowish, buds superposed...Carya glabra (= C. leioderma)
37b Pubescence not yellowish, buds not stacked...38
38a Bud rounded or only slightly pointed...42
38b Bud pointed distinctly...39
39a Twig green...Prunus persica
39b Twig brown, reddish, or gray...40
40a Twig intricately branched...Ulmus
crassifolia
40b Twig moderately or sparsely branched...42
41a Twig with green and gray splotches...Albizia
julibrissin
41b Twig brownish-gray...Quercus lyrata
42a Twig light gray-brown...Quercus nigra
42b Twig dark brown-red...Quercus falcata
43a Bud scales absent...Rhamnus caroliniana
43b Bud scales present...44
44a Buds 1/4 to 1/16 inch long, visible to the naked eye...48
44b Buds 1/16 inch long or smaller, with characters difficult to
distinguish...45
45a Twig intricately branched, with purplish-red splotches...Vaccinium arboreum
45b Twig without purplish-red splotches...46
46a Twig scurfy all over..Crataegus
berberifolia
46b Twig glabrous...47
47a Twig light orange-tan, very
slender...Salix nigra
47b Twig purplish...Prunus serotina
48a Bud pointy...49
48b Bud rounded...Cercis canadensis
49a Twig zig-zagging from node to node...50
49b Twig straight or curved, but not zig-zag...51
50a Leaf scars forming rings around cone-shaped buds...Platanus occidentalis
50b Leaf scars round, beneath buds...Morus
alba
51a Twig greenish with green buds...Sassafras
albidum
51b Twig and bud brown, gray, or reddish...52
52a Buds alternate...53
52b Buds opposite...Acer saccharinum
53a Lateral buds angled out from twigs...Quercus phellos
53b Lateral buds clasping twigs...54
54a Twigs with numerous visible
lenticels...Quercus shumardii
54b Twigs with barely visible lenticels, if
any...Ulmus americana
