Blackjack oak

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Blackjack oak leaves

Blackjack oak buds

Blackjack oak pistillate flower

Blackjack oak staminate catkins

Blackjack oak

Blackjack oak habit

Blackjack oak bark

Blackjack oak leaves

Blackjack oak leaf

Morphology

Trunk

Erect; bark black, furrows deep, ridges flat, blocky, plate-like; wood brown, hard.

Twigs

Reddish brown to grayish brown, rigid, scurfy or glabrate; leaf scars half-round; pith brown; buds reddish brown, ovoid, .2 to .24 inch, apex acute, scales sparsely rusty-pubescent.

Leaves

Deciduous, alternate, simple; petiole .2 to .8 inch, sparsely pubescent; blade broadly obovate-clavate to inversely triangular in outline, 2.8 to 8 inches long, 2.8 to 7.2 inches wide, base rounded to cordate, margins shallowly 3-lobed at apex, occasionally with 2 narrow lobes proximally, terminal 3 lobes broad, sometimes with 1-2 teeth, bristle-tipped, apex obtuse to acute, lower surface brownish green, hairs in fascicles and axillary tufts, upper surface dark yellow-green, shiny, glabrous or sparsely pubescent with hairs in fascicles.

Flowers

Staminate catkins at base of new growth, 30-50-flowered, pendent, 2 to 4.8 inches; peduncle .2 to .7 inch; pedicels absent; pistillate spikes axillary from new growth, 1-2-flowered; peduncle 0 to .16 inch; pedicels absent. Flowers unisexual, more or less radially symmetric; staminate: sepals 2-6, connate, calyx lobes .05 to .06 inch; petals absent; stamens 4-6; pistillate: sepals 6, connate, calyx free from ovary; petals absent; pistil 1; styles 3.

Fruit

October; acorns, maturing second year; peduncle elongating to .04 to .2 inch; cup top-shaped, .24 to .4 inch inch long, .52 to .7 inch wide, enclosing 1/3 to 1/2 of nut, scale apices closely appressed; nut yellowish brown, ovoid to nearly spherical, .52 to .67 inch long, .35 to .52 inch wide, minutely pubescent; seed 1.

Ecology

Habitat

Dry, sandy, gravelly, or clayey soil in upland woods, prairies, ridges, and bluffs.

Distribution

East 1/3 of Kansas

Practical Information

Uses

The Choctaw tribe used an infusion of tree bark as an analgesic and gynecological aid, and the Comanche tribe consumed the boiled acorns in times of scarcity. Squirrels, other small mammals, and birds consume the acorns.

Additional Notes