2. Leaf blades densely yellow-glandular on both surfaces; crushed leaves aromatic, scent reminiscent of bay leaves...Morella
2. Leaf blades not glandular on the surfaces; crushed leaves not aromatic or at least scent not bay leaf-like...3.
3. Leaves 7-20 cm long, usually at least some on a branch > 12 cm long, thick in texture but readily flexible when fresh; inflorescence of a solitary flower, axillary, 5-7cm across; fruit a capsule, ca. 1 cm in diameter...Gordonia
3. Leaves 3-12 cm long, thick in texture and also noticeably stiff; inflorescence of 1-several flowers in axillary clusters or cymes, or in catkins, the individual flowers < 1 cm across; fruit either a fleshy drupe, a nut (acorn), or an achene...4.
4. Fruit a cypsela (1-seeded, indehiscent fruit derived from inferior ovary), pappus bristles 7-10 mm long...Baccharis
4. Fruit either a fleshy drupe or a nut (acorn), pappus absent...5.
7. Secondary veins neatly pinnate, the veins on each side of the midrib evenly spaced, parallel to one another, and extending nearly or actually to the leaf margin; fruit either a 1-seeded nut (dry, with or without samaroid wings, bracts, a subtending cupule, or an enclosing and valvate involucre), a capsule, or a fleshy drupe with 2-4 stones...8.
8. Leaves doubly-serrate; fruit a nut or samaroid nut, lacking a cupule or valvate involucre, though sometimes associated with green, leaf-like bracts...9.
9. Flowers bisexual, in axillary fascicles, the tree androgynous; leaf base strongly asymmetrical (oblique) or nearly or quite symmetrical...10. [Ulmaceae]
10. Fruit nutlike (with numerous fleshy protuberances); primary lateral veins mostly forking before reaching the margin; small trees of swamp forests of the Coastal Plain from se. NC...Planera
10. Fruit a samara (flat and winged); primary lateral veins mostly parallel and unforked to the leaf margin; small to large trees, widespread in our area...Ulmus
9. Flowers unisexual, in catkins, the tree monoecious; leaf base symmetrical...11.
11. Scales of the pistillate catkins persistent; leafy involucre absent; fruit a small winged nut...12. [Betulaceae]
12. Pistillate scales woody, forming a persistent conelike catkin; plant a shrub or small tree, < 4 m tall...Alnus
12. Pistillate scales deciduous with or soon after the fruits; plant a tree, > 10 m tall at maturity...Betula
11. Scales of the pistillate catkins caducous; leafy involucre present, conspicuous; fruit an unwinged nut...13.
13. Infructescence bracts flat, 1-3 lobed, not enclosing the nut; bark gray, smooth; trunk moderately to strongly fluted; buds 4-angled...Carpinus
13. Infructescence bracts inflated, loosely enclosing the nut; bark brown, shreddy; trunk not fluted; buds not 4-angled...Ostrya
8. Leaves singly serrate or crenate; fruit either a fleshy drupe with 2-4 stones, or a nut with a cupule (acorn), a capsule, or enclosed by a valvate involucre that splits at maturity...14.
14. Fruit a fleshy drupe with 2-4 stones...15. [Rhamnaceae]
15. Winter buds naked, pubescent; flowers perfect, sepals, stamens, and petals 5; style undivided; leaves with 8-10 lateral veins on either side of the midvein...Frangula
15. Winter buds with bud scales; flowers functionally unisexual, sepals and stamens 4 or 5 (the stamens rudimentary in the pistillate flowers), petals 0 or 4 (never 5); style divided 1/3 to 2/3 its length into 2, 4 or 5 segments; leaves with (2-) 3-9 lateral veins on either side of the midvein...Rhamnus
14. Fruit either a capsule or a nut with a cupule (acorn) or 1-4 nuts enclosed by a valvate involucre that splits at maturity...16.
16. Fruit either a nut with a cupule (acorn) or 1-4 nuts enclosed by a valvate involucre that splits at maturity...17.
17. Fruits partially enclosed in a scaly cup (acorn); leaves lobed, toothed, crenate, or entire...Quercus
17. Fruits enclosed in a spiny or prickly bur; leaves toothed...18.
18. Nuts rounded or flattened on one or two sides; bur with long, straight spines; winter buds < 1 cm long; leaves elliptic or oblanceolate, some of them usually > 12 cm long...Castanea
18. Nuts sharply triangular; bur with short, recurved prickles; winter buds 1.5-2.5 cm long; leaves ovate, 6-12 cm long...Fagus
7. Secondary veins not as above, usually arching and/or branching or reticulating well before reaching the leaf margin; fruit various...19.
19. Leaves strongly 3-5-veined from the base; leaf blade cordate or truncate, often oblique...20.
20. Inflorescence terminal, a compound cyme; peduncles and pedicels becoming swollen, fleshy, and juicy at maturity; plant rarely naturalized...Hovenia
20. Inflorescence axillary, a solitary flower, a fascicle or cluster, or a cyme; peduncles and pedicels remaining stalk-like; collectively widespread and common...21.
21. Flowers unisexual, plants monoecious; pith of mature twigs chambered with hollow sections between soft partitions...Celtis
21. Flowers bisexual; plants hermaphroditic; pith of mature twigs continuous without hollow sections between partitions...22.
22. Flowers bisexual; inflorescence an axillary cyme; fresh leaves and stems lacking white latex; fruit simple, a 1-seeded nut; main leaf veins splitting several times towards the leaf margin and leading into the teeth without rejoining and forming a marginal vein; basal veins 5, palmate, all joining together at the summit of the petiole; main lateral leaf veins (above the basal veins) usually opposite; winter buds with 3 entire bud scales (1 much smaller than the other 2)...Tilia
22. Flowers unisexual, the pistillate inflorescence a head, the staminate inflorescence a catkin, borne on the same tree (monoecious) or on separate trees (dioecious); fresh leaves and stems with white latex; fruit a multiple of fleshy achenes; main leaf veins splitting towards the margin but then rejoining to form a rather prominent, looping marginal vein; basal veins 3, palmate, sometimes an additional prominent vein on each side joining the lateral vein above its divergence from the petiole end; main lateral leaf veins (above the basal veins) mainly alternate; winter buds with 5 ciliate-margined bud scales...23. [Moraceae]
23. Stems and leaves glabrous to pubescent...Morus
19. Leaves pinnately veined; leaf blade base cordate, subcordate, truncate, rounded, or cuneate base, not oblique...24.
24. Inflorescence a terminal raceme of racemes, with more than 50 flowers; petals connate, urceolate; fruit a 5-valved capsule, < 6 mm in diameter; fresh leaves with a sour taste...Oxydendrum
24. Inflorescence various, either with < 30 flowers or if with > 50 flowers a catkin (with a single axis); corolla with separate petals (or petals absent); fruit various, fleshy or dry; fresh leaves without a sour taste...25.
25. Pubescence stellate (look especially in vein axils on the undersurface of the leaf)...26. [Styracaceae]
26. Corolla lobes 4; fruit elongate, winged, 2.5-5 cm long; petioles 15-25 mm long...Halesia
26. Corolla lobes 5; fruit globose, not winged, 0.5-0.9 cm in diameter; petioles 2-10 mm long...Styrax
25. Pubescence simple...27.
27. Flowers unisexual, borne in axillary catkins; trees dioecious; fruit dehiscent, a lanceolate or ovoid capsule, 2-4-valved...28. [Salicaceae]
28. Leaf blades 0.8-2 (-3)x as long as wide; stamens 5-80; buds covered by several, overlapping scales; flowering catkins arching or drooping...Populus
28. Leaf blades (2-) 3-30x as long as wide; stamens 1-9; buds covered by a single scale; flowering catkins usually erect or ascending...Salix
27. Flowers bisexual (unisexual in Ilex), borne variously in terminal or axillary clusters, cymes, racemes, or umbels, but not at all catkin-like; trees hermaphroditic (dioecious in Ilex); fruit indehiscent, a fleshy drupe or pome with 1-many seeds, OR, if dehiscent, a capsule, 4-5-valved...29.
29. Fruit dehiscent, a 4-5-valved capsule...Stewartia
29. Fruit indehiscent, a fleshy drupe or pome with 1-many seeds...30.
30. Pith of twigs with transverse diaphragms and also continuous between the diaphragms (make a longitudinal section of
twig and use at least 10x magnification; look for translucent diaphragms spaced at < 1 mm apart, with whiter pith tissue
between them); fruit distinctly longer than broad, a 1-seeded drupe...Nyssa
30. Pith of twigs lacking diaphragms, continuous and homogeneous; fruit either suborbicular to spherical or pear-shaped,
either a several- to many-seeded pome, or a berry-like drupe with 4-8 seeds, or a 1-seeded drupe...31.
31. Vascular bundle scars 1 in each leaf scar; fruit a berrylike drupe with 4-8 bony pyrenes; ovary superior, the calyx
persistent at the base of the fruit...Ilex
31. Vascular bundle scars (2-) 3 in each leaf scar; fruit a pome or 1-seeded drupe; ovary either inferior and the calyx
persistent at the summit of the fruit (Amelanchier, Crataegus, Malus, Pyrus) or superior and the calyx not at all persistent at the base of the fruit (Prunus)...32. [Rosaceae]
33. Ovary and fruit 10-locular; inflorescence a raceme (rarely a fascicle); pome < 1 cm in diameter...Amelanchier
33. Ovary and fruit 5-locular; inflorescence a cyme, umbel, or fascicle (lacking an elongated central axis); pome 0.7-10 cm in diameter...34.
34. Styles distinct; exocarps (carpels within pericarp) bony and seedlike; trees and shrubs, with thorns...Crataegus
34. Styles usually connate at base; exocarps leather or papery and easily opened to expose seeds; small trees, unarmed, or armed with sharp spur branches...35.
35. Pome globose to ovoid, lacking stone cells; anthers yellow to white; styles connate at the base; leaves blunt to acuminate...Malus
35. Pome globose or pyriform, with stone cells; anthers reddish; styles distinct; leaves acute to acuminate...Pyrus
