Quercus rubra |
Quercus nigra |
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chêne rouge, northern red oak, red oak |
chêne gris, water oak |
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Habit | Trees, deciduous, to 30 m. Bark gray or dark gray, ridges wide, shiny, separated by shallow fissures, inner bark pinkish. | Trees, deciduous or tardily deciduous, to 30 m. Bark grayish black, fissures irregular, shallow, inner bark pinkish. |
Twigs | reddish brown, 2-3.5(-4.5) mm diam., glabrous. |
dark red-brown, 1.5-2.5 mm diam., glabrous. |
Leaves | blade ovate to elliptic or obovate, 120-200 × 60-120 mm, base broadly cuneate to almost truncate, margins with 7-11 lobes and 12-50 awns, lobes oblong, occasionally distally expanded, separated by shallow sinuses, sinuses usually extending less than 1/2 distance to midrib, apex acute; surfaces abaxially pale green, often glaucous, glabrous except for minute axillary tufts of tomentum, adaxially dull green, glabrous, secondary veins raised on both surfaces. |
blade distinctly obtrullate, rarely elliptic or merely obovate, widest near apex, 30-120(-160) × 15-60(-70) mm, base attenuate or cuneate, rarely rounded, margins entire with 1 apical awn or with 2-3 shallow lobes and 2-5 awns (leaves on juvenile or 2d-flush growth may be deeply lobed with more awns), apex obtuse to blunt or rounded; surfaces abaxially glabrous except for minute or conspicuous axillary tufts of tomentum, veins rarely raised, adaxially glabrous with secondary veins somewhat impressed. |
Acorns | biennial; cup saucer- to cup-shaped, 5-12 mm high × 18-30 mm wide, covering 1/4-1/3 nut, outer surface puberulent, inner surface light brown to red-brown, glabrous or with ring of pubescence around scar, scales less than 4 mm, often with dark margins, tips tightly appressed, obtuse; nut ovoid to oblong, 15-30 × 10-21 mm, glabrous, scar diam. 6.5-12.5 mm. |
biennial; cup saucer-shaped, 2.5-5.5 mm high × 10-18 mm wide, covering 1/4 nut or less, outer surface puberulent, inner surface sparsely to uniformly pubescent, scale tips tightly appressed, acute; nut broadly ovoid, 9.5-14 × 9.5-14.5 mm, often faintly striate, glabrate, scar diam. 6-11.5 mm. |
Terminal | buds dark reddish brown, ovoid to ellipsoid, 4-7 mm, glabrous or with tuft of reddish hairs at apex. |
buds reddish brown, ovoid, 3-6.5 mm, puberulent throughout, occasionally densely pubescent on apical 2/3. |
2n | = 24. |
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Quercus rubra |
Quercus nigra |
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Phenology | Flowering spring. | Flowering spring. |
Habitat | Commonly on mesic slopes and well-drained uplands, occasionally on dry slopes or poorly drained uplands | Mesic alluvial and lowland sites, also barrens, dunes, hammocks, and low ridges to steep slopes |
Elevation | 0-1800 m (0-5900 ft) | 0-450 m (0-1500 ft) |
Distribution |
AL; AR; CT; DC; DE; GA; IA; IL; IN; KS; KY; MA; MD; ME; MI; MN; MO; MS; NC; NE; NH; NJ; NY; OH; OK; PA; RI; SC; TN; VA; VT; WI; WV; NB; NS; ON; PE; QC
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AL; AR; DE; FL; GA; KY; LA; MD; MO; MS; NC; NJ; OK; SC; TN; TX; VA
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Discussion | Trees with large nuts only one-fourth covered by flat saucer-shaped cups often are treated as Quercus rubra var. rubra; those with smaller nuts one-third covered by cup- or bowl-shaped cups are treated as Q. rubra var. borealis (F. Michaux) Farwell. While E. J. Palmer (1942) suggested that these two varieties do not, K. M. McDougal and C. R. Parks (1986) found evidence of correspondence between morphologic types and flavonoid chemotypes. This is one of the most important ornamental and timber trees in the genus. Native Americans used Quercus rubra for a number of medical purposes, including the treatment of sores, weakness, lung problems, sore throat, dysentery, indigestion, chapped skin, chills and fevers, lost voice, asthma, cough, milky urine, hear trouble, blood diseases, and Italian itch, and as an appetizer (D. E. Moerman 1986). Quercus rubra reportedly hybridizes with Q. coccinea (= Q. ×benderi Baenitz) and Q. ellipsoidalis (P. C. Swain 1972; R. J. Jensen et al. 1993); with Q. ilicifolia (= Q. ×fernaldii Trelease), Q. imbricaria [Q. ×runcinata (A. de Candolle) Engelmann], and Q. marilandica (E. J. Palmer 1948; D. M. Hunt 1989); with Q. nigra (D. M. Hunt 1989); and with Q. palustris (= Q. ×columnaris Laughlin), Q. phellos (= Q. ×heterophylla F. Michaux), Q. shumardii (= Q. ×riparia Laughlin), and Q. velutina (= Q. ×hawkinsii Sudworth). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Typically on mesic alluvial and lowland sites, Quercus nigra also occurs on a wide variety of soil types and in a diversity of habitats. Trees with 3-lobed leaves with attenuate bases have been recognized as Quercus nigra var. tridentifera Sargent. Quercus nigra reportedly hybridizes with Q. falcata (= Q. ×garlandensis E. J. Palmer), Q. incana, Q. laevis (= Q. ×walteriana Ashe), Q. marilandica (= Q. ×sterilis Trelease), Q. phellos (= Q. ×capesii W. Wolf), Q. shumardii (= Q. ×neopalmeri Sudworth), and Q. velutina (Q. ×demarei Ashe). In addition, D. M. Hunt (1989) cited evidence of hybridization also with Q. arkansana, Q. georgiana, Q. hemisphaerica, Q. laurifolia, Q. myrtifolia, Q. palustris, Q. rubra, and Q. texana. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 3. | FNA vol. 3. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | Q. borealis, Q. maxima | Q. nana, Q. nigra var. tridentifera, Q. uliginosa |
Name authority | Linnaeus: Sp. Pl. 2: 996. (1753) | Linnaeus: Sp. Pl. 2: 995. (1753) |
Web links |
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