Quercus nigra |
Quercus emoryi |
|
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chêne gris, water oak |
bellota, Emory oak, Emory's oak |
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Habit | Trees, deciduous or tardily deciduous, to 30 m. Bark grayish black, fissures irregular, shallow, inner bark pinkish. | Trees or shrubs, evergreen, to 15 m. Bark dark brown to black, deeply fissured. |
Twigs | dark red-brown, 1.5-2.5 mm diam., glabrous. |
dark reddish brown, 1-3 mm diam., pubescent. |
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 ovate to narrowly oblong to obovate, planar, 28-95 × 15-45 mm, base cordate, margins entire or spinose, with up to 13 awns, apex blunt to acute; surfaces abaxially glabrous except for tuft of tomentum on each side of midrib at base of blade, rarely completely glabrous, adaxially not rugous, glabrous or with a few hairs along midrib. |
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. |
annual; cup cup-shaped, 5-7.5 mm high × 7-12 mm wide, covering 1/4-1/2 nut, outer surface pubescent to sparsely puberulent, inner surface pubescent to floccose, scale tips appressed, blunt; nut ellipsoid to oblong, 10-18 × 6-10 mm, glabrous to puberulent, especially at apex, scar diam. 3-5.5 mm. |
Terminal | buds reddish brown, ovoid, 3-6.5 mm, puberulent throughout, occasionally densely pubescent on apical 2/3. |
buds reddish brown, ovoid to subconic, 2.5-6.5 mm, glabrous except for tuft of hairs at apex, occasionally hairy on distal 1/2. |
Quercus nigra |
Quercus emoryi |
|
Phenology | Flowering spring. | Flowering spring. |
Habitat | Mesic alluvial and lowland sites, also barrens, dunes, hammocks, and low ridges to steep slopes | Foothills and slopes |
Elevation | 0-450 m (0-1500 ft) | 1000-2200 m (3300-7200 ft) |
Distribution |
AL; AR; DE; FL; GA; KY; LA; MD; MO; MS; NC; NJ; OK; SC; TN; TX; VA
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AZ; NM; TX; n Mexico
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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 emoryi reportedly hybridizes with Q. graciliformis (= Q. ×tharpii C. H. Muller). (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. Lobatae |
Sibling taxa | ||
Synonyms | Q. nana, Q. nigra var. tridentifera, Q. uliginosa | Q. hastata |
Name authority | Linnaeus: Sp. Pl. 2: 995. (1753) | Torrey: in W. H. Emory, Not. Milit. Reconn., 151, plate 9. (1848) |
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