Quercus nigra |
Quercus intricata |
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chêne gris, water oak |
dwarf oak, intricate oak |
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Habit | Trees, deciduous or tardily deciduous, to 30 m. Bark grayish black, fissures irregular, shallow, inner bark pinkish. | Shrubs, evergreen, clonal, intricately branched. |
Bark | gray, scaly. |
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Twigs | dark red-brown, 1.5-2.5 mm diam., glabrous. |
gray- or yellow-tomentose, darkened, 1-1.5 mm diam., persistently pubescent for several seasons. |
Buds | dark reddish brown, 1-1.5 mm, apex round, sparsely pubescent to glabrate. |
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Leaves | 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. |
blade oblong, sometimes ovate, often strongly cupped, 10-25 × 5-13 mm, extremely thick, leathery, base cuneate to cordate, margins very coarsely revolute, often undulate-crisped, entire, rarely with a few teeth, secondary veins 8 or 9 on each side, apex acute or obtuse; surfaces abaxially brownish or buff, persistently tomentose with erect curly hairs, rarely glabrate in 2d season, midribs (and sometimes principal veins) glabrous and brown against tomentum, secondary veins sometimes prominently raised, usually obscured by tomentum, adaxially dark or gray-green, lustrous, sparsely or moderately stellate-pubescent, secondary veins impressed. |
Acorns | 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. |
solitary or paired, subsessile or on peduncle to 15 mm; cup deeply cup-shaped, 7-8 mm deep × ca. 10 mm wide, base round, margin thin, scales ovate or narrower, proximally canescent-tomentose, moderately or markedly tuberculate, tips closely appressed, reddish, thin, nearly glabrous; nut light brown, ovoid, 9-12 × 8-10 mm. |
Cotyledons | connate. |
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Terminal | buds reddish brown, ovoid, 3-6.5 mm, puberulent throughout, occasionally densely pubescent on apical 2/3. |
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Quercus nigra |
Quercus intricata |
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Phenology | Flowering spring. | Flowering spring. |
Habitat | Mesic alluvial and lowland sites, also barrens, dunes, hammocks, and low ridges to steep slopes | Open chaparral and pinyon-oak woodland, on dry, rocky, limestone slopes (in Mexico also on gypsophilous soils) |
Elevation | 0-450 m (0-1500 ft) | 1500-2500 m (4900-8200 ft) |
Distribution |
AL; AR; DE; FL; GA; KY; LA; MD; MO; MS; NC; NJ; OK; SC; TN; TX; VA
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TX; Mexico (Coahuila, Nuevo León, Durango, and Zacatecas) |
Discussion | 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.) |
Quercus intricata, a fairly common element of the mountains of the Chihuahuan Desert region, is known in the United States only from two localities: a population in the Chisos Mountains and another in the Eagle Mountains of west Texas. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 3. | FNA vol. 3. |
Parent taxa | Fagaceae > Quercus > sect. Lobatae | Fagaceae > Quercus > sect. Quercus |
Sibling taxa | ||
Synonyms | Q. nana, Q. nigra var. tridentifera, Q. uliginosa | |
Name authority | Linnaeus: Sp. Pl. 2: 995. (1753) | Trelease: Mem. Natl. Acad. Sci. 20: 84. (1924) |
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