Quercus pumila |
Quercus nigra |
|
---|---|---|
runner oak, running oak |
chêne gris, water oak |
|
Habit | Shrubs, deciduous or tardily deciduous, to 1 m. Bark gray to dark brown. | Trees, deciduous or tardily deciduous, to 30 m. Bark grayish black, fissures irregular, shallow, inner bark pinkish. |
Twigs | gray-brown to reddish brown, 1-2 mm diam., sparsely to uniformly pubescent. |
dark red-brown, 1.5-2.5 mm diam., glabrous. |
Leaves | blade oblong to narrowly obovate, 25-100 × 10-33 mm, base acute to rounded, margins entire, revolute, with 1 apical awn, apex acute or obtuse to rounded; surfaces abaxially uniformly gray-brown pubescent, rarely glabrate, adaxially somewhat convex, rugose, glabrous or with scattered hairs along midrib. |
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 | annual; cup deeply saucer-shaped to turbinate, 5-12 mm high × 10-15 mm wide, covering 1/3-1/2(-2/3) nut, outer surface pubescent, inner surface densely pubescent, scales rarely involute, often tuberculate, tips tightly appressed, acute; nut globose to ovoid or broadly oblong, 9.5-15 × 9-12 mm, glabrate, scar diam. 5-8 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 brown to red-brown, ovoid, 2.5-4.5 mm, glabrous or with ciliate scale margins. |
buds reddish brown, ovoid, 3-6.5 mm, puberulent throughout, occasionally densely pubescent on apical 2/3. |
Quercus pumila |
Quercus nigra |
|
Phenology | Flowering spring. | Flowering spring. |
Habitat | Dry sandy soils of savannahs, low ridges and oak-pine scrub, occasionally at margins of poorly drained sites | Mesic alluvial and lowland sites, also barrens, dunes, hammocks, and low ridges to steep slopes |
Elevation | 0-100 m (0-300 ft) | 0-450 m (0-1500 ft) |
Distribution |
AL; FL; GA; MS; NC; SC
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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 | Although no hybrid combinations have been formally proposed, D. M. Hunt (1989) has reported evidence of hybridization with Quercus hemisphaerica, Q. incana, Q. myrtifolia, and Q. phellos. (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 | Fagaceae > Quercus > sect. Lobatae | Fagaceae > Quercus > sect. Lobatae |
Sibling taxa | ||
Synonyms | Q. nana, Q. nigra var. tridentifera, Q. uliginosa | |
Name authority | Walter: Fl. Carol., 234. (1788) | Linnaeus: Sp. Pl. 2: 995. (1753) |
Web links |