Quercus nigra |
Quercus tardifolia |
|
---|---|---|
chêne gris, water oak |
lateleaf oak |
|
Habit | Trees, deciduous or tardily deciduous, to 30 m. Bark grayish black, fissures irregular, shallow, inner bark pinkish. | Trees, evergreen. |
Bark | gray, furrowed. |
|
Twigs | dark red-brown, 1.5-2.5 mm diam., glabrous. |
dark reddish brown, 1.5-2.5 mm diam., densely 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 broadly elliptic or obovate, widest at or distal to middle, planar, 50-100 × 20-70 mm, base cordate or occasionally rounded, margins with 3-4 lobes with shallow sinuses, 6-12 awns, apex acute or obtuse; surfaces abaxially conspicuously tomentose, primary and secondary veins raised, adaxially somewhat rugose, glabrate. |
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. |
biennial, immature acorns in pairs, mature acorns not known. |
Terminal | buds reddish brown, ovoid, 3-6.5 mm, puberulent throughout, occasionally densely pubescent on apical 2/3. |
buds brown or reddish brown, ellipsoid or ovoid, 3.5-5.5 mm, apex hairy, scales with ciliate margins. |
Quercus nigra |
Quercus tardifolia |
|
Phenology | Flowering spring. | Flowering spring. |
Habitat | Mesic alluvial and lowland sites, also barrens, dunes, hammocks, and low ridges to steep slopes | Wooded arroyos |
Elevation | 0-450 m (0-1500 ft) | 2000 m (6600 ft) |
Distribution |
AL; AR; DE; FL; GA; KY; LA; MD; MO; MS; NC; NJ; OK; SC; TN; TX; VA
|
TX |
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.) |
Of conservation concern. Quercus tardifolia was reported from Mexico (Coahuila) (A. M. Powell 1988), but I have not seen the specimens. It should be expected in the ranges (e.g., Sierra del Carmen) adjacent to the Big Bend area. This distinctive species is apparently quite infrequent, only two small clumps being known from the Chisos Mountains (C. H. Muller 1951). Recent efforts to locate Quercus tardifolia have not been successful (M. Powell, pers. comm.). Its status is also in question; Muller and K. C. Nixon (pers. comm.) think that it might be a hybrid between Quercus gravesii and Q. hypoxantha. (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 | Linnaeus: Sp. Pl. 2: 995. (1753) | C. H. Muller: Bull. Torrey Bot. Club 63: 154. (1936) |
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