Trees or shrubs, with pinnatifid lobed dentate crenate or entire leaves, deciduous or in some species persistent. Flowers very small, green or yellowish, appearing with or before the leaves, the staminate numerous in slender mostly drooping aments, the pistillate solitary in many-bracted involucres borne on the twigs of the preceding season or on the young shoots. Staminate flowers subtended by caducous bracts, consisting of a mostly 6-lobed campanulate perianth and 3-12 stamens with filiform filaments, sometimes also with an abortive pilose ovary. Pistillate flowers involucrate,with an urn-shaped or oblong calyx, adnate to a mostly 3-celled ovary; ovules 2 in each cavity of the ovary, rarely more than 1 in each ovary maturing; styles as many as the ovary-cavities, short, erect or recurved. Fruit consisting of the imbricated and more or less united bracts of the involucre (cup), subtending or nearly enclosing the ovoid, oblong or subglobose i-seeded coriaceous nut (acorn). [The ancient Latin name, probably of Celtic derivation, signifying "beautiful tree."]

About 220 species, natives of the northern hemisphere. Besides the following, some 40 others occur in the western and southern sections of North America. Our species hybridize freely. Type species: Quercus Rbbur L.

* heaves or their lobes bristle-tipped, deciduous; acorns maturing in autumn of second year.

+ Leaves pinnatifid or pinnately lobed.

+ Leaves pinnatifid or pinnately lobed.

Leaves green on both sides.

Cup of the acorn saucer-shaped, much broader than high.

Cup 8"-12" broad; acorn ovoid; leaves dull.


Q. rubra.

Cup 4"-8" broad; leaves shining.

Acorn subglobose or short-ovoid; northern.


Q. palustris.

Acorn ovoid; southern.


Q. Schneckii.

Cup of the acorn turbinate or hemispheric.

Inner bark gray to reddish; leaves deeply lobed.

Leaves dull, not shining, pale beneath.


Q. borealis.

Leaves shining above.

Cup of acorn 5"-7" wide.


Q. ellipsoidalis.

Cup of acorn 8"-12" wide.


Q. coccinea.

Inner bark orange; leaves pubescent in the axils of the veins beneath.


Q. velutina.

Leaves white or gray-tomentulose beneath.

Large tree; leaf-lobes lanceolate or linear-lanceolate, long.

Leaves rounded or obtuse at the base, 3-5-lobed.


Q. triloba.

Leaves cuneate, obtuse or truncate at the base, 5-11-lobed.


Q. pagodaefolia.

Shrub or low tree; leaf-lobes triangular-ovate, short.


Q. nana.

++ Leaves 3-5-lobed above the middle or entire, obovate or spatulate in outline.

Leaves obovate-cuneate, brown-floccose beneath.


Q. marilandica.

Leaves spatulate to obovate, glabrous both sides.


Q. nigra.

+++Leaves entire, oblong, lanceolate or linear-oblong (sometimes lobed in no. 14).

Leaves linear-oblong, green and glabrous on both sides.


Q. Phellos.

Leaves oblong, glabrous, dark green and shining above.


Q. laurifolia.

Leaves oblong or lanceolate, brown-tomentulose beneath.


Q. imbricaria.

** Leaves or their lobes not bristle-tipped, deciduous; acorns maturing in autumn of first year.

+ Leaves pinnatifid or pinnately lobed.

Mature leaves pale, or glaucous and glabrate beneath; cup shallow.


Q. alba.

Mature leaves tomentulose beneath; cup one-third to fully as long as the acorn.

Upper scales of the cup not awned.

Leaves yellowish-brown-tomentulose beneath; acorn ovoid.


Q. stellata.

Leaves white-tomentulose beneath; acorn depressed-globose.


Q. lyrata.

Upper scales awned, forming a fringe around the acorn.


Q. macrocarpa.

++ Leaves crenate or dentate, not lobed.

Fruit peduncled.

Peduncle much longer than petioles; leaves white-tomentulose beneath.


Q. bicolor.

Peduncle equalling or shorter than the petioles; leaves gray-tomentulose beneath.

Teeth of the leaves acute or mucronulate.


Q. Michauxii.

Teeth of the leaves rounded.


Q. Prinus.

Fruit sessile or nearly so.

Tall tree; leaves oblong, obovate or lanceolate.



Shrub or low tree; leaves oval or obovate.


Q. prinoides.

*** Leaves entire (rarely with a few bristle-tipped lobes), evergreen.


Q. virginiana.