FNA: Quercus robur vs. Quercus douglasii

	Quercus robur	Quercus douglasii
	British oak, chêne pédoncule, English oak, French oak, pedunculate oak	blue oak
Habit	Trees, deciduous, to 30 m. Bark light gray, scaly.	Trees, deciduous, with single trunks, sometimes with few to several trunks.
Bark		gray, scaly.
Twigs	brown, 2-3 mm diam., glabrous.	reddish or yellowish, ca. 2 mm, densely or sparsely puberulent, occasionally glabrate with age.
Buds	dark brown, ovoid, distally obtuse, 2-3 mm, glabrous.	reddish brown, rarely yellowish, broadly ovoid to rarely subglobose, (2-)3-5 mm; scales glabrous except for ciliate margins, sometimes sparsely or densely pubescent.
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 or elliptic, oblong or oblanceolate, (20-)40-60(-80) × (15-)20-30(-40) mm, base rounded-attenuate or rounded, rarely cuneate, margins shallowly lobed or irregularly toothed, sometimes entire, lobes mucronate or rounded, secondary veins 6-10 on each side, apex rounded, rarely moderately acute; surfaces abaxially light green or blue-green, waxy, with scattered to crowded, semi-erect, (2-)4-6(-8)-rayed stellate hairs usually 0.2-0.6 mm diam. or larger, adaxially blue-green, glaucous or grayish, vestiture similar to abaxial surface.
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.	subsessile, solitary; cup hemispheric or cup-shaped, rarely deeper, 5-10 mm deep × 10-15 mm wide, enclosing only base of nut, scales thin and not tuberculate to strongly and irregularly tuberculate, particularly toward base of cup; nut thin-walled, fusiform or subcylindric, 20-30 × 10-16 mm.
Cotyledons	distinct.	distinct.
2n	= 24.	= 24.

	Quercus robur	Quercus douglasii
Phenology	Flowering spring.	Flowering late winter–spring.
Habitat	Roadsides, pastures, forest margins and woodlands	Oak woodlands, margins of chaparral and grasslands
Elevation	0-1000 m (0-3300 ft)	0-1200 m (0-3900 ft)
Distribution	BC; NB; NS; PE [Introduced from Europe] [WildflowerSearch map] [BONAP county map]	CA [WildflowerSearch map] [BONAP county map]
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.)	Populations of Quercus douglasii in coastal southern California and on the Channel Islands consist of small stands or solitary individuals often associated with Q. lobata and scrub oaks. Some doubt exists as to whether some or all of those populations are natural stands or are historical introductions near Native American settlements. Along the canyons of Santa Barbara County, putative hybrids between Q. douglasii and Q. dumosa are referred to Q. ×kinselae (C. H. Muller) Nixon. In the interior Coast Ranges of California are found numerous populations that are intermediate in form between Q. douglasii and Q. john-tuckeri (= Q. turbinella var. californica). This appears to be an area of secondary contact, and the two species remain distinct in nearby populations. Because of the widespread nature of the intermediates, following Tucker's extensive studies they can be conveniently referred to as the nothospecies Q. ×alvordiana Eastwood. The plants tend to be shrubs to small trees, with somewhat more spinose leaves than Q. douglasii and fruit similar to those of the latter species. (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	Q. acerifolia, Q. agrifolia, Q. ajoensis, Q. alba, Q. arizonica, Q. arkansana, Q. austrina, Q. berberidifolia, Q. bicolor, Q. boyntonii, Q. buckleyi, Q. carmenensis, Q. chapmanii, Q. chihuahuensis, Q. chrysolepis, Q. coccinea, Q. cornelius-mulleri, Q. depressipes, Q. douglasii, Q. dumosa, Q. durata, Q. ellipsoidalis, Q. emoryi, Q. engelmannii, Q. falcata, Q. fusiformis, Q. gambelii, Q. garryana, Q. geminata, Q. georgiana, Q. graciliformis, Q. gravesii, Q. grisea, Q. havardii, Q. hemisphaerica, Q. hinckleyi, Q. hypoleucoides, Q. ilicifolia, Q. imbricaria, Q. incana, Q. inopina, Q. intricata, Q. john-tuckeri, Q. kelloggii, Q. laceyi, Q. laevis, Q. laurifolia, Q. lobata, Q. lyrata, Q. macrocarpa, Q. margarettae, Q. marilandica, Q. michauxii, Q. minima, Q. mohriana, Q. montana, Q. muehlenbergii, Q. myrtifolia, Q. nigra, Q. oblongifolia, Q. oglethorpensis, Q. pacifica, Q. pagoda, Q. palmeri, Q. palustris, Q. phellos, Q. polymorpha, Q. prinoides, Q. pumila, Q. pungens, Q. robusta, Q. rubra, Q. rugosa, Q. sadleriana, Q. shumardii, Q. similis, Q. sinuata, Q. stellata, Q. tardifolia, Q. texana, Q. tomentella, Q. toumeyi, Q. turbinella, Q. vacciniifolia, Q. vaseyana, Q. velutina, Q. viminea, Q. virginiana, Q. wislizenii	Q. acerifolia, Q. agrifolia, Q. ajoensis, Q. alba, Q. arizonica, Q. arkansana, Q. austrina, Q. berberidifolia, Q. bicolor, Q. boyntonii, Q. buckleyi, Q. carmenensis, Q. chapmanii, Q. chihuahuensis, Q. chrysolepis, Q. coccinea, Q. cornelius-mulleri, Q. depressipes, Q. dumosa, Q. durata, Q. ellipsoidalis, Q. emoryi, Q. engelmannii, Q. falcata, Q. fusiformis, Q. gambelii, Q. garryana, Q. geminata, Q. georgiana, Q. graciliformis, Q. gravesii, Q. grisea, Q. havardii, Q. hemisphaerica, Q. hinckleyi, Q. hypoleucoides, Q. ilicifolia, Q. imbricaria, Q. incana, Q. inopina, Q. intricata, Q. john-tuckeri, Q. kelloggii, Q. laceyi, Q. laevis, Q. laurifolia, Q. lobata, Q. lyrata, Q. macrocarpa, Q. margarettae, Q. marilandica, Q. michauxii, Q. minima, Q. mohriana, Q. montana, Q. muehlenbergii, Q. myrtifolia, Q. nigra, Q. oblongifolia, Q. oglethorpensis, Q. pacifica, Q. pagoda, Q. palmeri, Q. palustris, Q. phellos, Q. polymorpha, Q. prinoides, Q. pumila, Q. pungens, Q. robur, Q. robusta, Q. rubra, Q. rugosa, Q. sadleriana, Q. shumardii, Q. similis, Q. sinuata, Q. stellata, Q. tardifolia, Q. texana, Q. tomentella, Q. toumeyi, Q. turbinella, Q. vacciniifolia, Q. vaseyana, Q. velutina, Q. viminea, Q. virginiana, Q. wislizenii
Synonyms	Q. pedunculata	Q. douglasii var. ransomii, Q. ransomii
Name authority	Linnaeus: Sp. Pl. 2: 996. (1753)	Hooker & Arnott: Bot. Beechey Voy. 9: 391. (1840)
Web links	Local floras: BC, CA, OR, WA Local Web sites: CalFlora, CalPhotos, Flora NW, PNW Herbaria WildflowerSearch iNaturalist (observations) USDA Plants Database LBJ Wildflower Center SEINet Plants of the World Online Encyclopedia of Life Wikipedia Google Image Search	Local floras: CA Local Web sites: CalFlora, CalPhotos WildflowerSearch iNaturalist (observations) USDA Plants Database LBJ Wildflower Center SEINet Plants of the World Online Encyclopedia of Life Wikipedia Google Image Search

Quercus douglasii

British oak, chêne pédoncule, English oak, French oak, pedunculate oak

blue oak

Habit

Trees, deciduous, to 30 m. Bark light gray, scaly.

Trees, deciduous, with single trunks, sometimes with few to several trunks.

Bark

gray, scaly.

Twigs

brown, 2-3 mm diam., glabrous.

reddish or yellowish, ca. 2 mm, densely or sparsely puberulent, occasionally glabrate with age.

Buds

dark brown, ovoid, distally obtuse, 2-3 mm, glabrous.

reddish brown, rarely yellowish, broadly ovoid to rarely subglobose, (2-)3-5 mm;

scales glabrous except for ciliate margins, sometimes sparsely or densely pubescent.

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 or elliptic, oblong or oblanceolate, (20-)40-60(-80) × (15-)20-30(-40) mm, base rounded-attenuate or rounded, rarely cuneate, margins shallowly lobed or irregularly toothed, sometimes entire, lobes mucronate or rounded, secondary veins 6-10 on each side, apex rounded, rarely moderately acute;

surfaces abaxially light green or blue-green, waxy, with scattered to crowded, semi-erect, (2-)4-6(-8)-rayed stellate hairs usually 0.2-0.6 mm diam. or larger, adaxially blue-green, glaucous or grayish, vestiture similar to abaxial surface.

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.

subsessile, solitary;

cup hemispheric or cup-shaped, rarely deeper, 5-10 mm deep × 10-15 mm wide, enclosing only base of nut, scales thin and not tuberculate to strongly and irregularly tuberculate, particularly toward base of cup;

nut thin-walled, fusiform or subcylindric, 20-30 × 10-16 mm.

Cotyledons

distinct.

= 24.

Quercus robur

Quercus douglasii

Phenology

Flowering spring.

Flowering late winter–spring.

Habitat

Roadsides, pastures, forest margins and woodlands

Oak woodlands, margins of chaparral and grasslands

Elevation

0-1000 m (0-3300 ft)

0-1200 m (0-3900 ft)

Distribution

BC; NB; NS; PE [Introduced from Europe]

[WildflowerSearch map]

[BONAP county map]

[WildflowerSearch map]

[BONAP county map]

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.)

Populations of Quercus douglasii in coastal southern California and on the Channel Islands consist of small stands or solitary individuals often associated with Q. lobata and scrub oaks. Some doubt exists as to whether some or all of those populations are natural stands or are historical introductions near Native American settlements. Along the canyons of Santa Barbara County, putative hybrids between Q. douglasii and Q. dumosa are referred to Q. ×kinselae (C. H. Muller) Nixon. In the interior Coast Ranges of California are found numerous populations that are intermediate in form between Q. douglasii and Q. john-tuckeri (= Q. turbinella var. californica). This appears to be an area of secondary contact, and the two species remain distinct in nearby populations. Because of the widespread nature of the intermediates, following Tucker's extensive studies they can be conveniently referred to as the nothospecies Q. ×alvordiana Eastwood. The plants tend to be shrubs to small trees, with somewhat more spinose leaves than Q. douglasii and fruit similar to those of the latter species.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Source

FNA vol. 3.

Parent taxa

Fagaceae > Quercus > sect. Quercus

Sibling taxa

Q. acerifolia, Q. agrifolia, Q. ajoensis, Q. alba, Q. arizonica, Q. arkansana, Q. austrina, Q. berberidifolia, Q. bicolor, Q. boyntonii, Q. buckleyi, Q. carmenensis, Q. chapmanii, Q. chihuahuensis, Q. chrysolepis, Q. coccinea, Q. cornelius-mulleri, Q. depressipes, Q. douglasii, Q. dumosa, Q. durata, Q. ellipsoidalis, Q. emoryi, Q. engelmannii, Q. falcata, Q. fusiformis, Q. gambelii, Q. garryana, Q. geminata, Q. georgiana, Q. graciliformis, Q. gravesii, Q. grisea, Q. havardii, Q. hemisphaerica, Q. hinckleyi, Q. hypoleucoides, Q. ilicifolia, Q. imbricaria, Q. incana, Q. inopina, Q. intricata, Q. john-tuckeri, Q. kelloggii, Q. laceyi, Q. laevis, Q. laurifolia, Q. lobata, Q. lyrata, Q. macrocarpa, Q. margarettae, Q. marilandica, Q. michauxii, Q. minima, Q. mohriana, Q. montana, Q. muehlenbergii, Q. myrtifolia, Q. nigra, Q. oblongifolia, Q. oglethorpensis, Q. pacifica, Q. pagoda, Q. palmeri, Q. palustris, Q. phellos, Q. polymorpha, Q. prinoides, Q. pumila, Q. pungens, Q. robusta, Q. rubra, Q. rugosa, Q. sadleriana, Q. shumardii, Q. similis, Q. sinuata, Q. stellata, Q. tardifolia, Q. texana, Q. tomentella, Q. toumeyi, Q. turbinella, Q. vacciniifolia, Q. vaseyana, Q. velutina, Q. viminea, Q. virginiana, Q. wislizenii

Q. acerifolia, Q. agrifolia, Q. ajoensis, Q. alba, Q. arizonica, Q. arkansana, Q. austrina, Q. berberidifolia, Q. bicolor, Q. boyntonii, Q. buckleyi, Q. carmenensis, Q. chapmanii, Q. chihuahuensis, Q. chrysolepis, Q. coccinea, Q. cornelius-mulleri, Q. depressipes, Q. dumosa, Q. durata, Q. ellipsoidalis, Q. emoryi, Q. engelmannii, Q. falcata, Q. fusiformis, Q. gambelii, Q. garryana, Q. geminata, Q. georgiana, Q. graciliformis, Q. gravesii, Q. grisea, Q. havardii, Q. hemisphaerica, Q. hinckleyi, Q. hypoleucoides, Q. ilicifolia, Q. imbricaria, Q. incana, Q. inopina, Q. intricata, Q. john-tuckeri, Q. kelloggii, Q. laceyi, Q. laevis, Q. laurifolia, Q. lobata, Q. lyrata, Q. macrocarpa, Q. margarettae, Q. marilandica, Q. michauxii, Q. minima, Q. mohriana, Q. montana, Q. muehlenbergii, Q. myrtifolia, Q. nigra, Q. oblongifolia, Q. oglethorpensis, Q. pacifica, Q. pagoda, Q. palmeri, Q. palustris, Q. phellos, Q. polymorpha, Q. prinoides, Q. pumila, Q. pungens, Q. robur, Q. robusta, Q. rubra, Q. rugosa, Q. sadleriana, Q. shumardii, Q. similis, Q. sinuata, Q. stellata, Q. tardifolia, Q. texana, Q. tomentella, Q. toumeyi, Q. turbinella, Q. vacciniifolia, Q. vaseyana, Q. velutina, Q. viminea, Q. virginiana, Q. wislizenii

Synonyms

Q. pedunculata

Q. douglasii var. ransomii, Q. ransomii

Name authority

Linnaeus: Sp. Pl. 2: 996. (1753)

Hooker & Arnott: Bot. Beechey Voy. 9: 391. (1840)

Web links

Local floras: BC, CA, OR, WA
Local Web sites: CalFlora, CalPhotos, Flora NW, PNW Herbaria
WildflowerSearch
iNaturalist (observations)
USDA Plants Database
LBJ Wildflower Center
SEINet
Plants of the World Online
Encyclopedia of Life
Wikipedia
Google Image Search

Unless otherwise noted, all data comes from the online version of the Flora of North America, who have made most of their content available via a Creative Commons license (CC BY 4.0).

Choose a data source: Flora of North America, OregonFlora, UW Burke Herbarium

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Flora of North America species comparison

Quercus robur

Quercus douglasii

Quercus robur

Quercus douglasii