Quercus stellata |
Fagaceae |
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post oak |
beech family, oak family |
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Habit | Trees, deciduous, to 20(-30) m. Bark light gray, scaly. | Trees or shrubs, evergreen or deciduous, shrubs sometimes rhizomatous. | ||||||||||||||||
Twigs | yellowish or grayish, (2-)3-5 mm diam., densely stellate-pubescent. |
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Buds | reddish brown, ovoid, to 4 mm, apex obtuse or acute, sparsely pubescent. |
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Leaves | blade obovate to narrowly obovate, elliptic or obtriangular, 40-150(-200) × 20-100(-120) mm, rather stiff and hard, base rounded-attenuate to cordate, sometimes cuneate, margins shallowly to deeply lobed, lobes rounded or spatulate, usually distal 2 lobes divergent at right angles to midrib in cruciform pattern, secondary veins 3-5 on each side, apex broadly rounded; surfaces abaxially yellowish green, with crowded yellowish glandular hairs and scattered minute, 6-8-rayed, appressed or semi-appressed stellate hairs, not velvety to touch, adaxially dark or yellowish green, dull or glossy, sparsely stellate, often somewhat sandpapery with harsh hairs. |
blade lobed or unlobed, pinnately veined, margins serrate, dentate, or entire; surfaces usually pubescent, at least when young, sometimes with scales. |
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Inflorescences | unisexual or androgynous catkins; staminate and androgynous catkins spicate or capitate, rigid, flexible, or lax, consisting of few- to many-flowered clusters, bracts present or absent; pistillate catkins rigid or flexible, with 1-several spicately arranged, rarely solitary, terminal cupules bearing 1-3(-15 or more) pistillate flowers. |
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Staminate flowers | bracteate, bracts often caducous; sepals (3-)4-6(-8); stamens (3-)6-12(-18 or more); petals absent; anthers 2-locular, dehiscing by longitudinal slits, pollen sacs contiguous; pistillode often present and indurate, or vestigial as central tuft of trichomes. |
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Pistillate flowers | calyx of 4-6 distinct or connate sepals; petals absent; pistil 1, 3(-6 or more)-carpellate; ovary inferior, locules as many as carpels; placentation axile; ovules pendulous, 2 in each locule, all but 1 in each pistil usually aborting; styles as many as carpels, distinct to base; stigmas dry; staminodes present or absent. |
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Fruits | nuts, sometimes winged, 1-seeded, subtended or enclosed individually or in groups of 2-3(-15) by scaly or spiny, multibracteate cupule; seed coat membranous; endosperm none; embryo straight, as long as seed; cotyledons fleshy, starchy or oily. |
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Acorns | 1-3, subsessile or on peduncle to 6(-40) mm; cup deeply saucer-shaped, proximally rounded or constricted, 7-12(-18) mm deep × (7-)10-15(-25) mm wide, enclosing 1/4-2/3 nut, scales tightly appressed, finely grayish pubescent; nut light brown, ovoid or globose, 10-20 × 8-12(-20) mm, glabrous or finely puberulent. |
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Cotyledons | distinct. |
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Winter | buds sessile, with few to many imbricate scales (2 valvate scales enclosing imbricate scales in Castanea); terminal bud present or absent. |
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Quercus stellata |
Fagaceae |
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Phenology | Flowering spring. | |||||||||||||||||
Habitat | Usually on xeric sites, dry gravelly and sandy ridges and uplands, dry clays, prairies and limestone hills, woodlands and deciduous forests | |||||||||||||||||
Elevation | 0-750 m (0-2500 ft) | |||||||||||||||||
Distribution |
AL; AR; CT; DE; FL; GA; IA; IL; IN; KS; KY; LA; MA; MD; MO; MS; NC; NJ; NY; OH; OK; PA; RI; SC; TN; TX; VA; WV
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Widespread; often dominant forest trees in temperate; subtropical; and tropical areas; mostly Northern Hemisphere |
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Discussion | Quercus stellata is often identified by its commonly cross-shaped leaf form, particularly in the eastern part of its range. All individuals and populations do not express this characteristic, however. Moreover, Q. stellata has broad overlap with Q. margaretta and even with some forms of the blackjack oak, Q. marilandica, one of its most common associates. The thick yellowish twigs with indument of stellate hairs and the dense harsh stellate hairs on the abaxial leaf surface are better diagnostic characteristics when variation includes leaf forms that are not obviously cruciform. Native Americans used Quercus stellata medicinally for indigestion, chronic dysentery, mouth sores, chapped skin, hoarseness, and milky urine, as an antiseptic, and as a wash for fever and chills (D. E. Moerman 1986). Putative hybrids are known with Quercus marilandica, Q. alba, and various other white oaks. Quercus stellata is also one of the few oaks that appears to produce hybrids with species in the live oak group, although obvious intermediates are rarely encountered. Nothospecies names based on putative hybrids involving Q. stellata include: Q. ×stelloides E. J. Palmer (= Q. prinoides × Q. stellata), Q. ×mahloni E. J. Palmer (as Q. sinuata var. breviloba × Q. stellata), Q. ×pseudomargaretta Trelease (= Q. margaretta × Q. stellata), Q. ×sterretti Trelease (= Q. lyrata × Q. stellata), Q. ×macnabiana Sudworth (= Q. sinuata × Q. stellata), Q. ×guadalupensis Sargent (= Q. sinuata × Q. stellata), Q. ×fernowi Trelease (= Q. alba × Q. stellata), and Q. ×bernardensis W. Wolf (= Q. montana × Q. stellata). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Genera 9, species probably 600-800 (5 genera, 97 species, and numerous hybrids in the flora). In the Western Hemisphere, Fagaceae are found from southern Canada to Colombia; they are absent or infrequent in most of the northern Great Plains and northern Rocky Mountain region. Fagaceae are one of the most important families of Northern Hemisphere woody plants in terms of total biomass and economic use. They are widely used for lumber, firewood, and horticultural plantings; the nuts are often used for animal fodder and, in some species, for human food (particularly Castanea). As dominants in forests, woodlands, and chaparral, native stands of fagaceous trees and shrubs provide optimal wildlife habitat, often harboring an exceptionally diverse insect fauna. Most of the diversity of the family in the Western Hemisphere is concentrated in the genus Quercus, with the greatest number of species in Mexico (at least 125 species), and a secondary area of diversity in the southeastern United States. Polyploidy has not been reported in any natural populations of species of Fagaceae. Natural interspecific hybridization is common in the family, particularly in Quercus, and also in Castanea and Lithocarpus. The most important diagnostic feature of Fagaceae is the cupule, which occurs as the cup or cap of the acorn in Quercus and Lithocarpus and the spiny bur that surrounds the fruits of Castanea and Chrysolepis. The cupule is sometimes referred to as an involuc involucre, however, is made up of bracts, while the cupule has been shown to be a complex structure that is interpreted as an indurated, condensed, partial inflorescence formed by fusion of stem axes with several orders of branching, bearing bracts that are modified as scales and/or spines (see B. S. Fey and P. K. Endress 1983). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Key |
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Source | FNA vol. 3. | FNA vol. 3, p. 436. | ||||||||||||||||
Parent taxa | Fagaceae > Quercus > sect. Quercus | |||||||||||||||||
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Synonyms | Q. minor, Q. obtusiloba | |||||||||||||||||
Name authority | Wangenheim: Beytr. Teut. Forstwiss., 78, plate 6, fig. 15. (1787) | Dumortier | ||||||||||||||||
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