Ulmus americana L. American elm, white elm. Family Ulmaceae. ITIS Taxonomic Serial Number 19049. USDA PLANTS Symbol ULAM. TROPICOS # 33300003.
Images Branchlet with leaves. Individual leaf. Branchlet with buds. Close-up of buds. Branchlet with flowers. Branchlet with fruits. Close-up of fruits. Herbarium sheet 1. Herbarium sheet 2. Herbarium sheet 3. Herbarium sheet 4.
Plant habit and life style. Plants Angiosperms, synoecious, (10)2035(50) m tall.
Stems. Pith continuous. Young twigs (1-year-old or less) brown or reddish-brown, glabrous or glabrate or pubescent. Leaf scars crescent-shaped or half-round or triangular, bundle scars 3(6) per leaf scar, stipule scars present or inconspicuous, stipule scars not circumferential. Bark of mature trunks flaky or furrowed or ridged.
Buds. Buds axillary, brown or reddish-brown, 36 mm long, ovoid, blunt or sharp, glabrous or pubescent, puberulent, bud scales imbricate.
Leaves. Leaves deciduous, simple, petiolate, alternate, distichous, (5)715 cm long, 2.47.5(9) cm wide, obovate or oval or ovate, leaf margins doubly serrate, leaf apices acuminate or acute, leaf bases cordate or cuneate or oblique or rounded. Leaf upper surface green, glabrous. Leaf lower surface green, glabrous or glabrate or pubescent or with tufts in vein axils. Leaf venation pinnate. Petioles 0.21 cm long, glabrous or glabrate or pubescent. Stipules present, 1350 mm long, caducous, not circumferential.
Flowers. Flowering January or February or March or April. Inflorescences axillary, fascicles, flowers stalked. Flowers bisexual, hypogynous. Perianth. Calyx asymmetric or radially symmetric, synsepalous. Sepals 69 per flower, brown or green, sepal margins ciliate, pubescent, puberulent, persistent. Corolla absent. Androecium. Stamens 59 per flower. Gynoecium. Ovaries superior, pistils 1 per flower. Gynoecium syncarpous, 2 carpels per flower, styles 2 per pistil, placentation apical.
Fruits. Fruits samaras, 0.81.2 cm long, cream or purple or tan or yellow, fruit maturation 1 years.
Habitat. Habitat bottomland forests or mesic upland forests or mixed forest edges or suburban plantings.
Special Diagnostic Characters. Twigs without corky wings; lateral leaf veins typically straight and parallel to one another; overall form often "vase-shaped", with the main branches spreading from the tall trunk in a graceful arch.
Cite this publication as: ‘Stephen M. Seiberling, Alan S. Weakley, and Peter S. White (2005 onwards). Common Trees of the North Carolina Piedmont: Identification, Descriptions, Illustrations, and Glossary. Version: March 7, 2006. <http://www.ibiblio.org/openkey/intkey/>’.
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