Quercus ellipsoidalis |
Fagaceae |
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Hill's oak, Jack oak, northern pin oak |
beech family, oak family |
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Habit | Trees, deciduous, to 20 m; lower trunk often with stubs of dead branches. | Trees or shrubs, evergreen or deciduous, shrubs sometimes rhizomatous. | ||||||||||||||||
Bark | dark gray-brown, shallowly fissured, inner bark orangish. |
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Twigs | dark reddish brown, (1-)1.5-3 mm diam., glabrous. |
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Leaves | blade elliptic, 70-130 × 50-100 mm, base obtuse to truncate, margins with 5-7 deep lobes and 15-55 awns, lobes distally expanded, sinuses usually extending more than 1/2 distance to midrib, apex acute; surfaces abaxially glabrous except for minute axillary tufts of tomentum, adaxially glossy light green, glabrous, secondary veins raised on both surfaces. |
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 | biennial; cup narrowly turbinate to deeply cup-shaped, 6-11 mm high × 10-19 mm wide, covering 1/3-1/2 nut, outer surface reddish brown, puberulent, inner surface light brown, glabrous, rarely with ring of pubescence around scar, scales with straight or slightly concave margins, tips tightly appressed, obtuse or acute; nut ellipsoid to ovoid, rarely subglobose, 10-20 × 9-15 mm, occasionally striate, glabrous, occasionally with 1 or more faint rings of fine pits at apex, scar diam. 4-8 mm. |
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Terminal | buds dark reddish brown, ovoid, 3-5 mm, often conspicuously 5-angled in cross section, usually silvery- or tawny-pubescent toward apex. |
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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 ellipsoidalis |
Fagaceae |
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Phenology | Flowering spring. | |||||||||||||||||
Habitat | Dry sandy sites, rarely on moderately mesic slopes or uplands | |||||||||||||||||
Elevation | 150-500 m (500-1600 ft) | |||||||||||||||||
Distribution |
IA; IL; IN; MI; MN; OH; WI; ON
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Widespread; often dominant forest trees in temperate; subtropical; and tropical areas; mostly Northern Hemisphere |
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Discussion | In many treatments (e.g., E. G. Voss 1972+, vol. 2), Quercus ellipsoidalis is included in Q. coccinea. Variation in fruit morphology has led to recognition of several formae (W. Trelease 1919; see also R. J. Jensen 1986) and one variety (Q. ellipsoidalis var. kaposianensis, based on specimens from St. Paul, Minnesota, in which the cup tightly encloses the nut for two-thirds its length at maturity). Quercus ellipsoidalis reportedly hybridizes with Q. rubra and Q. velutina. The Menominee used Quercus ellipsoidalis medicinally to treat suppressed menses caused by cold (D. E. Moerman 1986). (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. Lobatae | |||||||||||||||||
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Synonyms | Q. ellipsoidalis var. kaposianensis | |||||||||||||||||
Name authority | E. J. Hill: Bot. Gaz. 27: 204, plates 2, 3. (1899) | Dumortier | ||||||||||||||||
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