Trees , deciduous, to 25 m. Bark light gray, scaly. Twigs green or reddish, becoming gray, 2-3(-4) mm diam., initially pubescent, soon glabrous. Buds dark reddish brown, ovoid, ca. 3 mm, apex obtuse, glabrous. Leaves: petiole (4-)10-25(-30) mm. Leaf blade obovate to narrowly elliptic or narrowly obovate, (79-)120-180(-230) × (40-)70-110(-165) mm, base narrowly cuneate to acute, margins moderately to deeply lobed, lobes often narrow, rounded distally, sinuses extending 1/3-7/8 distance to midrib, secondary veins arched, divergent, (3-)5-7 on each side, apex broadly rounded or ovate; surfaces abaxially light green, with numerous whitish or reddish erect hairs, these quickly shed as leaf expands, adaxially light gray-green, dull or glossy. Acorns 1-3, subsessile or on peduncle to 25(-50) mm; cup hemispheric, enclosing 1/4 nut, scales closely appressed, finely grayish tomentose; nut light brown, ovoid-ellipsoid or oblong, (12-)15-21(-25) × 9-18 mm, glabrous. Cotyledons distinct. 2 n = 24. Flowering in spring. Moist to fairly dry, deciduous forests usually on deeper, well-drained loams, also on thin soils on dry upland slopes, sometimes on barrens; 0-1600 m; Ont., Que.; Ala., Ark., Conn., Del., Fla., Ga., Ill., Ind., Kans., Ky., La., Maine, Md., Mass., Mich., Minn., Miss., Mo., Nebr., N.H., N.J., N.Y., N.C., Ohio, Okla., Pa., R.I., S.C., Tenn., Tex., Vt., Va., W.Va., Wis. Considerable variation in depth of lobing occurs in the leaves of Quercus alba (M. J. Baranski 1975; J. W. Hardin 1975); the species is easily distinguished from others, however, by the light gray-green, glabrous mature leaves and cuneate leaf bases. In the past Quercus alba was considered to be the source of the finest and most durable oak lumber in America for furniture and shipbuilding. Now it has been replaced almost entirely in commerce by various species of eastern red oak (e.g., Q . rubra , Q . velutina , and Q . falcata ) that are more common and have faster growth and greater yields. These red oaks also lack tyloses and therefore are more suited to pressure treating with preservatives, even though they are less decay-resistant without treatment.
Medicinally, Quercus alba was used by Native Americans to treat diarrhea, indigestion, chronic dysentery, mouth sores, chapped skin, asthma, milky urine, rheumatism, coughs, sore throat, consumption, bleeding piles, and muscle aches, as an antiseptic, and emetic, and a wash for chills and fevers, to bring up phlegm, as a witchcraft medicine, and as a psychological aid (D. E. Moerman 1986).
Numerous hybrids between Quercus alba and other species of white oak have been reported, and some have been named. J. W. Hardin (1975) reviewed the hybrids of Quercus alba . Nothospecies names based on putative hybrids involving Q . alba include: Q . × beadlei Trelease (= Q . alba × prinus ), Q . × bebbiana Schneider (= Q . alba × macrocarpa ), Q . × bimundorum E. J. Palmer (= Q . alba × robur ), Q . × deami Trelease (= Q . alba × muhlenbergii ), Q . × faxoni Trelease (= Q . alba × prinoides ), Q . × jackiana Schneider (= Q . alba × bicolor ), and Q . × saulei Schneider (= Q . alba × montana ).
Tree 22 - 28 m tall, trunk 0.6 - 1.2 m in diameter Leaves: alternate, short-stalked, bright green above, pale green or with a waxy whitish coating beneath (glaucous), 12 - 20 cm long, 6 - 10 cm wide, with five to nine rounded lobes separated by depressions that are deep in sun leaves and shallow in shade leaves. Foliage turns brownish purple in fall. Flowers: either male or female, found on the same plant (monoecious). Male flowers are borne in hanging catkins, yellow, and 5 - 8 cm long, while the reddish female flowers are borne near leaf axils. Fruit: an acorn, developing in one season, solitary or in pairs, with a 0 - 2.5 cm long stalk. The deep saucer- or bowl-shaped cup covers one-quarter of the nut and has thick and warty scales with fine gray hairs. Nut light brown, 1.3 - 2 cm long and oblong to egg-shaped. Bark: light gray with shallow fissures or long, scaly blocks. Frequently, infection by a harmless fungus, <i>Aleurodiscus oakesii</i>, causes the non-living outer bark to fall off, leaving smooth, gray patches. Twigs: changing from bright green and hairy to reddish or light gray and smooth with age. Buds: dark reddish brown, 3 - 4 mm long, egg-shaped to almost spherical with a rounded tip. Each terminal bud is surrounded by a cluster of lateral buds. Form: open with wide-speading, gnarled branches.
Similar species: Many oaks in the white oak group and Quercus robur have highly variable, similar leaves with rounded lobes. Quercus bicolor has round-toothed to shallowly lobed leaves that are whitish and hairy beneath, peeling bark on young branches, and a long-stalked acorn cup. Quercus lyrata has leaves that are inversely egg-shaped with irregular, rounded lobes, and an acorn cup that nearly covers the nut. Quercus macrocarpa has deeply lobed leaves that are inversely egg-shaped and hairy beneath, often corky-ridged twigs, and an acorn cup with long fringes along the margin. Quercus robur has very short-stalked leaves with ear-like lobes at the base, and a long-stalked acorn cup.
Flowering: mid April to early June
Habitat and ecology: Very common in oak-hickory forests and upland dry-mesic areas.
Occurence in the Chicago region: native
Notes: Quercus alba, the state tree of Illinois, is one of the most important lumber trees in the United States. Prior to the use of steel, its wood was used to build United States Navy ships. It is still used for furniture, cabinets, and flooring, however, some faster growing red oak species have replaced it. Quercus alba naturally hybridizes with Q. macrocarpa (Q. x bebbiana), Q. muhlenbergii (Q. x deamii), and Q. montana (Q. x saulei).
Etymology: Quercus is the Latin name for oak. Alba comes from the Latin word for white.
Tall tree with light gray, coarsely flaky, shallowly furrowed bark and widely spreading branches; twigs soon glabrescent; lvs obovate or oblong-obovate, cuneate at base, thinly floccose beneath at first (the pubescence can be rolled off with one's thumb), glabrous or nearly so at maturity, pale beneath, the lobes 3 or 4(5) pairs, ascending, oblong to ovate, rounded or rarely acute; acorns sessile or on pedicels to 4 cm, the cup deeply saucer-shaped, pubescent within, covering a fourth to a third of the nut; nut ovoid to cylindric-ovoid, 1.5-2.5 cm. Upland woods; Me. to Mich. and Minn., s. to n. Fla. and e. Tex. Extreme forms in which the lobes are scarcely more than large teeth may be distinguished from the chestnut-oaks by the lack of pubescence.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.