Quercus robur |
Quercus chrysolepis |
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British oak, chêne pédoncule, English oak, French oak, pedunculate oak |
canyon live oak, gold cup live oak, maul oak |
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Habit | Trees, deciduous, to 30 m. Bark light gray, scaly. | Trees or shrubs, trees small to medium-sized, to 25 m, shrubs of variable size. |
Twigs | brown, 2-3 mm diam., glabrous. |
branching at 60° angles or less, golden brown, 1-2 mm diam., flexible, densely pubescent 1st year, moderately so 2d year. |
Buds | dark brown, ovoid, distally obtuse, 2-3 mm, glabrous. |
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Leaves | blade obovate to narrowly elliptic or narrowly obovate (some cultivars oblanceolate), (50-)70-150(-200) × (20-)35-85(-100) mm, base strongly cordate, often minutely revolute or folded, margins moderately to deeply lobed, lobes rounded or retuse distally, sinuses extending 1/3-7/8 distance to midrib, secondary veins arched, divergent, (3-)5-7 on each side, apex broadly rounded; surfaces abaxially light green, glabrous or sparsely pubescent, glabrous at maturity, adaxially deep green to light green or gray, dull or glossy. |
blade oblong, acuminate, usually flat to slightly concave, 20-70 × 10-35 mm, thick, leathery, base obtuse to rounded, secondary veins 12 or more pairs, branching at ca. 50° angles, slightly raised abaxially, margins often slightly revolute with moderately thickened cell walls, entire to spinulose-dentate (especially on juvenile growth), regularly toothed, teeth terminating with mucronate to spinescent tip, apex acute or obtuse, mucronate to spinescent; surfaces abaxially glabrate to pubescent with bluish white wax layer, often obscured by golden glandular and multiradiate hairs, adaxially yellowish green, scurfy with multiradiate hairs, later in season slightly pubescent. |
Acorns | 1-3, on very thin (1-2 mm diam.), flexuous peduncle (25-)35-65(-100) mm; cup hemispheric to deeply goblet-shaped, enclosing 1/4-1/2 nut or more, scales closely appressed, often in concentric rows, finely grayish tomentose; nut brown, ovoid, oblong, or cylindric, 15-30(-35) × 12-20 mm, glabrous. |
solitary or paired, rarely in 3s or 4s; cup saucer-shaped, 4-10 mm deep × 15-40 mm wide, rims often corky and thickened, scales appressed, deeply embedded in tomentum, often appearing swollen and keeled, tuberculate; nut ovoid, 15-30 × 10-20 mm, apex blunt, glabrous; nut scar 4-10 mm diam. |
Cotyledons | distinct. |
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Terminal | buds conic, 2-8 mm, scales brown with ciliate margins. |
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2n | = 24. |
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Quercus robur |
Quercus chrysolepis |
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Phenology | Flowering spring. | Flowering usually in spring, occasionally in fall. |
Habitat | Roadsides, pastures, forest margins and woodlands | Mountain ridges, canyons, and moist slopes |
Elevation | 0-1000 m (0-3300 ft) | 200-2600 m (700-8500 ft) |
Distribution |
BC; NB; NS; PE [Introduced from Europe]
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AZ; CA; NM; NV; OR; Mexico (Baja California and Chihuahua)
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Discussion | Quercus robur is one of the oaks most commonly cultivated in temperate and subtropical parts of the world. In North America it is most commonly seen in the eastern and northwestern parts of the United States and and in southeastern and southwestern Canada, where it tolerates a wide array of conditions and is extremely hardy. In Washington, New Brunswick, and Nova Scotia, apparently reproducing populations persist in the wild. Elsewhere, although actual naturalization appears to be rare, Q. robur should be expected to persist around old homesites and other places of cultivation. Quercus robur most closely resembles our native species Q. alba in leaf form. In contrast with Q. alba, which has relatively long petioles (longer than 10 mm), acute leaf bases, and subsessile fruit (rarely on peduncles to 25 mm), Q. robur is easily distinguished by its shorter petioles (less than 10 mm), cordate, almost clasping, leaf bases, and fruit on long (more than 35 mm), thin peduncles. Quercus robur is one of the oaks most widely celebrated in literature; it has wood of exceptionally high quality for the manufacture of furniture, and it previously was the most important wood used in the manufacture of wooden sailing vessels in Europe. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Quercus chrysolepis is one of the most variable North American oaks. Historically, individuals with extreme variation in fruit and leaf characteristics led to the recognition of several varieties and forms; for example, shrubs with small leaves have been called Q. chrysolepis var. nana (Jepson) Jepson. Studies of quantitative and qualitative variation in these characteristics do not support the recognition of infraspecific taxa; geographic variation is apparent, however, based on populations with nearly stabilized character combinations that loosely define widespread variants. This oak is distinguished consistently from other species of the complex by the presence of multiradiate trichomes on both leaf surfaces (P. S. Manos 1993). The leaf morphology and branching habit present on juvenile growth, suckers, and shade forms may approach typical Q. palmeri. Similarly, various extreme forms often resemble other species of the complex. Putative hybrids have been reported from narrow zones of range overlap with the three other North American species of Quercus sect. Protobalanus. The Mendocin Indians considered the nuts of Quercus chrysolepis poisonous (D. E. Moerman 1986). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 3. | FNA vol. 3. |
Parent taxa | Fagaceae > Quercus > sect. Quercus | Fagaceae > Quercus > sect. Protobalanus |
Sibling taxa | ||
Synonyms | Q. pedunculata | Q. chrysolepis var. nana, Q. wilcoxii |
Name authority | Linnaeus: Sp. Pl. 2: 996. (1753) | Liebmann: Overs. Kongel. Danske Vidensk. Selsk. Forh. Medlemmers Arbeider 1854: 173. (1854) |
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