Part 4

American Elm Ulmus americana L.

Bark gray to blackish, thick, divided into flat ridges by deep furrows. Branches ascending, arching, and spreading; open-grown trees vase-shaped in outline. Twigs 2 to 3 mm in diameter with 5 to 7 leaves which increase in size from basal to apical leaf, red-brown. Buds (leaf) brown, small, scaly, acute. Leaves alternate, deciduous, simple; broadly ovate, 5 to 15 cm long, 4 to 6 cm wide; apex acuminate, margin usually doubly serrate, base oblique on short petiole; upper surface smooth, marked with sunken veins pinnately arranged; veins more prominent on underside. Flowers perfect, buds greatly enlarge before opening; with very small flowers abundant in clusters; opening before the leaves expand, blooming from late December into February. Fruit a samara, oval to circular with wing surrounding the seed, about 10 mm in diameter, margin ciliate.

Sugarberry; hackberry Celtis laevigata Willd.

Bark light gray to almost white, thin, smooth, usually more or less studded with irregular corky outgrowths. Branches spreading, slender. Twigs about 3 mm in diameter, reddish-brown. Buds about 3 mm long, alternate. Leaves alternate, deciduous, simple; narrowly elliptic to broadly ovate, 6 to 10 cm long, 2 to 4 cm wide; apex acute, margin usually entire, base broadly rounded or oblique. Flowers unisexual or perfect, tiny, inconspicuous, many staminate and few pistillate appearing on the new growth as the leaves unfold. Fruit a drupe with a bony reticulated nutlet, about 5 mm in diameter, orange-red on a pedicel often shorter than the petiole of the subtending leaf.

Yellow-poplar Liriodendron tulipifera L.

Bark thin and dark green on young trees, becoming ash-gray and conspicuously furrowed and ridged with age. Branches spreading to ascending, often drooping on large open-grown trees. Twigs smooth, about 5 mm in diameter, encircled by stipule scars, red-brown. Buds (terminal) grayish green, turning red in winter, flat about 10 to 16 mm long, scales valvate. Leaves alternate, deciduous, simple; dark green above, turning yellow in fall; 6 to 20 cm long and as wide as long; petioles 5 to 20 cm long, often longer than the blades on low branches. Flowers perfect, tulip-shaped, about 4 to 6 cm long, greenish-yellow with orange to reddish markings at base of petals, color intensifies with age. Fruit an aggregate cone, 5 to 8 cm long, gradually shattering into one-seeded, winged samaras.

Sweetbay Magnolia virginiana L.

Bark dark gray, usually smooth, thin, in shady areas often encrusted with mosses, liverworts, and lichens. Branches stout, spreading to ascending. Twigs about 5 to 7 mm in diameter, encircled by stipule scars, green. Buds (terminal), silvery gray, pubescent, 15 mm long; smaller lateral buds often subtended by persistent petiole base. Leaves alternate, evergreen in South, deciduous in northern part of range, simple; elliptic to oblong, 10 to 15 cm long, 4 to 6 cm wide; margin entire, dark green above, silvery pubescent below. Flowers perfect, white, sweet-scented, 5 to 8 cm in diameter, appearing May to September. Fruit an aggregate of follicles which open and shed red seeds, irregular in shape, ovoid to ellipsoid, smooth, about 5 cm long.

Sweetgum; redgum Liquidambar styraciflua L.

Bark dark gray, divided by deep furrows into narrow, rounded ridges. Branches stout, often with corky wings or outgrowths. Twigs about 4 to 6 mm in diameter, gray-brown. Buds (terminal) broadly egg-shaped, about 10 to 15 mm long, scales overlapping, slightly sticky. Leaves alternate, deciduous, simple; palmately 5- to 7-lobed; 8 to 20 cm wide, 6 to 15 cm long, often longer than broad; margin finely serrate; petioles 4 to 13 cm long. Flowers unisexual (plants monoecious), appearing as the leaves unfold; staminate clustered in terminal racemes; pistillate in small drooping spherical heads. Fruit in stalked spherical heads covered with small spine-like projections; seed cavity at base of each spine.

Red Maple Acer rubrum L.

Bark gray, divided into scaly ridges by narrow furrows. Branches slender, spreading and ascending. Twigs about 3 mm in diameter, reddish. Buds spherical, reddish, clustered at apex of twig, scales with white ciliate margins. Leaves opposite, deciduous, simple; ovate to almost circular, 4 to 9 cm long, 2.5 to 7 cm wide, usually longer than broad; 3-lobed near the apex, margin finely serrate; dark green above, glaucous and lightly pubescent below, pubescence usually shed. Flowers typically polygamous, occasionally with perfect flowers, small, forming dense clusters from separate buds before leaf expansion, conspicuous because of the red to orange coloration. Fruit twin samaras 10 to 20 mm long.

Var. drummondii: Leaves larger than typical red maple, usually broader than long; 3 to 5 lobes or occasionally scarcely lobed, margins coarsely toothed, conspicuously glaucous below, usually permanently tomentose. Fruit samaras 4 to 5 cm long.

Black Tupelo; blackgum Nyssa sylvatica Marsh.

Bark black, marked with furrows and cross-cracks that divide the ridges into squarish plates. Branches slender, spreading to horizontal, often drooping in open-grown specimens. Twigs 2 to 3 mm in diameter, gray to reddish. Buds obtuse, of overlapping yellow-brown scales, terminal buds 6 mm long. Leaves alternate, early deciduous, simple; marked with irregular black spots and purple coloration from midsummer on; elliptic to broadly oval to obovate, 5 to 15 cm long, 3 to 8 cm wide; apex acute to broadly rounded, margin entire, base wedge-shaped. Flowers unisexual, less than 4 mm in diameter, appearing in April before leaf expansion. Fruit a black drupe 8 to 10 mm long, 1 to 3 on pedicels 3 to 5 cm long, stone faintly ribbed.

White Ash Fraxinus americana L.

Bark gray to brownish, divided into narrow, deep furrows and ridges of equal width. Branches stout, wide-spreading. Twigs 3 to 6 mm in diameter. Buds (terminal) broadly ovoid consisting of 4 appressed scales, dark brown to black; lateral buds spherical, tightly appressed to a crescent-shaped leaf scar. Leaves opposite, deciduous, odd-pinnately compound; 20 to 30 cm long, white below when fresh; leaflets 7 to 9, petiolulate, oval to ovate, 5 to 15 cm long, 3 to 5 cm wide, apex acuminate, margin essentially entire, base broadly rounded, pinnate veins conspicuous on underside. Flowers unisexual (plants dioecious); pistillate inconspicuous about 1 mm in diameter, arranged in dense paniculate clusters; staminate conspicuous in mass. Fruit a samara, 25 to 60 mm long, wing terminal on the thickened seed.

Green Ash Fraxinus pennsylvanica Marsh.

Bark brownish, smooth when young, then breaking into narrow ridges with shallow narrow furrows. Branches drooping to spreading and ascending. Twigs stout, 4 to 6 mm in diameter, olive green. Buds terminal black; smaller lateral buds tightly appressed to the generally straight upper edge of the leaf scar. Leaves opposite, deciduous, odd-pinnately compound with 5 to 7, occasionally 9, leaflets; leaflets narrowly to broadly elliptical, apex acuminate, margin entire to finely serrate, base wedge-shaped, hairy below along the veins. Flowers unisexual (plants dioecious); pistillate inconspicuous in open panicles; staminate in compact conspicuous clusters. Fruit a samara 25 to 50 mm long, seed end conspicuously slender and extending about half the length of the samara, wing decurrent on seed end.

Selected References

Bailey, L. H. 1949. Manual of cultivated plants. Rev. ed. 1116 p. Macmillan Co., New York.

Brown, C. A. 1945. Louisiana trees and shrubs. Bull. 1, 262 p. Louisiana Forestry Commission, Baton Rouge.

Coker, W. C., and H. R. Totten. 1945. Trees of the southeastern states. 3rd ed. 419 p. Univ. of N. C. Press, Chapel Hill.

Collingwood, G. H., and W. D. Brush. 1974. Knowing your trees. Rev. by D. Butcher. 374 p. American Forestry Association, Washington, D.C.

Correll, D. C., and M. C. Johnston. 1970. Manual of the vascular plants of Texas. Contributions from the Texas Research Foundation, Vol. 6. 1881 p. Texas Research Foundation, Renner, Texas.

Fernald, M. L. 1950. Gray’s Manual of Botany. 8th ed. 1632 p. American Book Co., New York.

Harlow, W. M. 1959. Fruit key and twig key to trees and shrubs. 106 p. Dover Publications, New York.

Harlow, W. M., and E. S. Harrar. 1941. Textbook of dendrology covering the important forest trees of the United States and Canada. 2nd ed. 561 p. McGraw-Hill Book Co., New York and London.