Quercus robur |
Quercus oblongifolia |
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British oak, chêne pédoncule, English oak, French oak, pedunculate oak |
Mexican blue oak, Sonoran blue oak |
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Habit | Trees, deciduous, to 30 m. Bark light gray, scaly. | Trees, evergreen, to 10 m. Bark gray or whitish, closely furrowed. |
Twigs | brown, 2-3 mm diam., glabrous. |
light brown, 1-1.5 mm diam., densely or sparsely stellate-tomentose, soon glabrate. |
Buds | dark brown, ovoid, distally obtuse, 2-3 mm, glabrous. |
reddish brown, subspheric to broadly ovoid, 1-2 mm, glabrous or basal scales pubescent; stipules persistent about terminal buds. |
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 to elliptic, occasionally lanceolate or ovate, (20-)30-60(-80) × (5-)10-25(-30) mm, base cuneate to cordate, margins entire, undulate, sometimes irregularly toothed especially toward apex, secondary veins 7-8(-10) on each side, branched, apex acute or broadly rounded; surfaces abaxially densely and loosely glandular-tomentose, quickly glabrate or persistently floccose, especially about base of midrib, at maturity strongly glaucous, adaxially dull pale green, bluish green, or glaucous, sparsely stellate-tomentose, quickly glabrate. |
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, subsessile or on peduncle 4-12 mm; cup cup-shaped, about 6-8(-13) mm deep × 10-13 mm wide, enclosing ca. 1/3 nut, scales to 1-1.5 mm wide, moderately, regularly tuberculate near base of cup, gray-pubescent; nut light brown, ovoid or oblong, 12-17(-19) × (7-)10-12 mm, glabrate or puberulent about apex. |
Cotyledons | distinct. |
connate. |
2n | = 24. |
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Quercus robur |
Quercus oblongifolia |
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Phenology | Flowering spring. | Flowering in spring. |
Habitat | Roadsides, pastures, forest margins and woodlands | Common in high grasslands and midelevation woodlands, mesas, and canyons |
Elevation | 0-1000 m (0-3300 ft) | 1300-1650 m (4300-5400 ft) |
Distribution |
BC; NB; NS; PE [Introduced from Europe]
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AZ; NM; TX; Mexico (Baja California South, Sonora, Chihuahua, and Coahuila)
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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.) |
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Source | FNA vol. 3. | FNA vol. 3. |
Parent taxa | Fagaceae > Quercus > sect. Quercus | Fagaceae > Quercus > sect. Quercus |
Sibling taxa | ||
Synonyms | Q. pedunculata | |
Name authority | Linnaeus: Sp. Pl. 2: 996. (1753) | Torrey: in L. Sitgreaves, Rep. Exped. Zuni Colorado Rivers, 173, plate 19. (1853) |
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