Common Trees of the North Carolina Piedmont

Stephen M. Seiberling, Alan S. Weakley, and Peter S. White

Platanus occidentalis L. Sycamore, American plane-tree, American sycamore, plane-tree. Synonyms Platanus occidentalis var. glabrata (Fern.) Sarg. Family Platanaceae. ITIS Taxonomic Serial Number 19020. USDA PLANTS Symbol PLOC. TROPICOS # 25300003.

Images • Individual leaf. • Branchlet with buds. • Close-up of bud. • Close-up of fruits. • Herbarium sheet 1. • Herbarium sheet 2. • Herbarium sheet 3. • Herbarium sheet 4.

Detailed Description:

Plant habit and life style. Plants Angiosperms, monoecious, (10–)15–35(–50) m tall.

Stems. Pith continuous. Young twigs (1-year-old or less) brown or green, glabrous or glabrate or pubescent, stellate. Twigs (2–4 years old) glabrous. Leaf scars horseshoe-shaped, bundle scars 5–9 per leaf scar, stipule scars present, stipule scars circumferential. Bark of mature trunks exfoliating or flaky or furrowed or ridged or smooth.

Buds. Buds axillary or infrapetiolar, brown, 6–10 mm long, conic, blunt, glabrous, bud scales imbricate or single scale.

Leaves. Leaves deciduous, simple, petiolate, alternate, 6–20(–35) cm long, 6–25(–40) cm wide, orbiculate or oval or reniform, leaf margins serrate, unlobed or shallowly lobed or moderately lobed or deeply lobed, palmately lobed, leaf lobes (1–)3–5(–7) per leaf, leaf apices acuminate or acute, leaf bases cordate or cuneate or truncate. Leaf upper surface green, glabrate or pubescent, stellate or tomentose. Leaf lower surface green, glabrate or pubescent or with tufts in vein axils, stellate or tomentose. Leaf venation palmate. Petioles 5–12 cm long, glabrous or pubescent. Stipules present, 25–38 mm long, caducous, blade-like, circumferential.

Flowers. Flowering March or April or May or June. Inflorescences axillary, heads, flowers sessile or stalked. Flowers unisexual or pistillate or staminate, hypogynous. Perianth. Calyx radially symmetric. Sepals 3–8 per flower. Corolla radially symmetric. Petals 3–8 per flower. Androecium. Stamens 3–8 per flower, separate, staminodes present. Gynoecium. Ovaries superior, pistils 3–9 per flower. Gynoecium apocarpous, 3–9 carpels per flower, styles 1 per pistil, styles 1.5–6 mm long, placentation parietal.

Fruits. Fruits accessory fruits or achenes or aggregate fruits, (0.3–)2–3(–3.8) cm long, brown or tan, fruit maturation 1 years.

Habitat. Habitat bottomland forests or disturbed and weedy areas or mesic upland forests or mixed forest edges or suburban plantings.

Special Diagnostic Characters. Mature bark peeling away in thin sheets exposing whitish, greenish or yellowish new bark, on older trunks becoming dark brown and scaly or fissured; new buds developing inside the base of the petiole and remaining hidden until the leaf falls; fruits in globose heads that often persist on the tree through the winter.

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. <>’.

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