Quercus robur |
Quercus bicolor |
|
---|---|---|
British oak, chêne pédoncule, English oak, French oak, pedunculate oak |
chêne bicolore, swamp white oak |
|
Habit | Trees, deciduous, to 30 m. Bark light gray, scaly. | Trees, deciduous, to 30 m. Bark dark gray, scaly or flat-ridged. |
Twigs | brown, 2-3 mm diam., glabrous. |
light brown or tan, 2-3(-4) mm diam., glabrous. |
Buds | dark brown, ovoid, distally obtuse, 2-3 mm, glabrous. |
light or dark brown, globose to ovoid, 2-3 mm, glabrous. |
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 obovate to narrowly elliptic or narrowly obovate, (79-)120-180(-215) × (40-)70-110(-160) mm, base narrowly cuneate to acute, margins regularly toothed, or entire with teeth in distal 1/2 only, or moderately to deeply lobed, or sometimes lobed proximally and toothed distally, secondary veins arched, divergent, (3-)5-7 on each side, apex broadly rounded or ovate; surfaces abaxially light green or whitish, with minute, flat, appressed-stellate hairs and erect, 1-4-rayed hairs, velvety to touch, adaxially dark green, glossy, glabrous. |
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. |
1-3(-5) mm, on thin axillary peduncle (20-)40-70 mm; cup hemispheric or turbinate, 10-15 mm deep × 15-25 mm wide, enclosing 1/2-3/4 nut, scales closely appressed, finely grayish tomentose, those near rim of cup often with short, stout, irregularly recurved and sometimes branched, spinose awns emerging from tubercle; nut light brown, ovoid-ellipsoid or oblong, (12-)15-21(-25) × 9-18 mm, glabrous. |
Cotyledons | distinct. |
distinct. |
2n | = 24. |
= 24. |
Quercus robur |
Quercus bicolor |
|
Phenology | Flowering spring. | Flowering in spring. |
Habitat | Roadsides, pastures, forest margins and woodlands | Low swamp forests, moist slopes, poorly drained uplands |
Elevation | 0-1000 m (0-3300 ft) | 0-1000 m (0-3300 ft) |
Distribution |
BC; NB; NS; PE [Introduced from Europe]
|
AL; CT; DE; IA; IL; IN; KY; MA; MD; ME; MI; MN; MO; NC; NH; NJ; NY; OH; PA; RI; TN; VA; VT; WI; WV; ON; QC
|
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.) |
Putative hybrids between Quercus bicolor and Q. macrocarpa are common in areas of contact. The hybrids tend to have more deeply lobed leaves and varying degrees of development of awns as a fringe along the margin of the acorn cup. Such characteristics occur sporadically throughout many populations of Q. bicolor; in some cases they may occur because of subtle introgression. The Iroquois used Quercus bicolor in the treatment of cholera, broken bones, consumption, and as a witchcraft medicine (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. Quercus |
Sibling taxa | ||
Synonyms | Q. pedunculata | Q. bicolor var. angustifolia, Q. bicolor var. cuneiformis, Q. bicolor var. platanoides, Q. platanoides |
Name authority | Linnaeus: Sp. Pl. 2: 996. (1753) | Willdenow: in G. H. E. Muhlenberg, Ges. Naturf. Freunde Berlin Neue Schriften 3: 396. (1801) |
Web links |
|