IUCN threat status:

Not evaluated

Comprehensive Description

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This tree is 40-80' tall at maturity, forming a single trunk about 1½-3' across and a crown of leafy branches. Young trees have somewhat pyramidal crowns, while older trees have more open crowns that are more or less ovoid. Upper branches are ascending, while lower branches are widely spreading or slightly drooping. Trunk bark of mature trees is gray to brown, rough-textured, and narrowly furrowed with scaly ridges. Branch bark is gray and more smooth, while twigs are brown and glabrous with scattered lenticels. Alternate leaves occur along the twigs and young shoots; they tend to be more common near the tips of twigs and shoots. Individual leaf blades are 3-6" long and ¾-2" across; they are oblong-elliptic to broadly oblong-elliptic in shape and smooth along their margins. At the tip of each leaf blade, there is either a tiny bristle or the scar of a detached bristle. The upper surface of the leaf blades is dark green, hairless, and glossy, while the lower surface is dull gray-green and sparsely canescent to densely short-pubescent. The texture of the leaf blades is somewhat stiff and leathery. The petioles are ½-¾" long, yellowish white to light green, and glabrous to short-pubescent. Shingle Oak is monoecious, producing separate male (staminate) and female (pistillate) flowers on the same tree. Male flowers are produced in drooping yellowish catkins about 3" long. Each male flower is less than 1/8" across, consisting of an irregularly lobed calyx and several stamens. Female flowers occur near the tips of twigs as the vernal leaves unfold; either short clusters of 2-4 female flowers or individual female flowers are produced. Each female flower is less than ¼" long, greenish red, and ovoid in shape, consisting of an ovary, a calyx that surrounds the ovary, and 3 stigmata at the apex. Underneath each female flower, there are scale-like bractlets with downy hairs. The blooming period occurs during mid- to late spring for about 2 weeks; the flowers are cross-pollinated by wind. Afterwards, fertile female flowers are replaced by acorns that take 2 years to develop; they become mature during the autumn of the second year. Acorns usually occur along the twigs either individually or in clusters of 2; they have short woody pedicels. Mature acorns are about 10-15 mm. long and a little less across, consisting of a light brown cup and a brown nut. Each cup extends about one-third the length of an acorn. The meat of the acorn is bitter. The root system consists of a taproot with spreading lateral roots.


Creative Commons Attribution Non Commercial 3.0 (CC BY-NC 3.0)

© John Hilty

Source: Illinois Wildflowers

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