FNA: Quercus engelmannii vs. Quercus buckleyi

	Quercus engelmannii	Quercus buckleyi
	Engelmann oak, Engelmann's oak	Buckley's oak, Texas oak, Texas red oak
Habit	Trees, subevergreen, to 10 m. Bark gray or whitish, closely furrowed.	Trees, deciduous, to 15 m. Bark gray and smooth or black and furrowed.
Twigs	light brown, 1-1.5 mm diam., densely or sparsely stellate-tomentose, soon glabrate.	grayish brown to red-brown, rarely somewhat yellowish or gray, 1.5-3 mm diam., glabrous.
Buds	reddish brown, subspheric to broadly ovoid, 1-2 mm, glabrous or basal scales pubescent; stipules persistent about terminal buds.
Leaves	blade oblong to elliptic, occasionally lanceolate or ovate, (20-)30-60(-80) × (5-)10-20(-25) 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 blue-green or pale green, densely and loosely glandular-tomentose, quickly glabrate or persistently floccose, especially about base of midrib, at maturity strongly glaucous, adaxially gray-green or pale green, bluish green or glaucous.	blade circular or broadly elliptic to obovate, 55-100 × 51-112 mm, base cuneate to truncate, often inequilateral, margins with 7-9 lobes and 12-35 awns, lobes oblong to distally expanded, apex acute to acuminate; surfaces abaxially light green or coppery green, glabrous or with small, axillary tufts of tomentum, adaxially shiny or glossy, glabrous, veins raised on both surfaces.
Acorns	solitary or paired, subsessile or on peduncle to 5-6 mm; cup cup-shaped or shallowly cup-shaped, 8-10 mm deep × 10-15 mm wide, enclosing 1/3 nut, scales 1.5-3 mm wide, strongly and regularly tuberculate near base of cup, gray-pubescent; nut light brown, ovoid or oblong, 15-25 × 12-14 mm, glabrate or puberulent about apex.	biennial; cup goblet- to cup-shaped, rarely saucer-shaped, 5-11.5 mm high × 10-18 mm wide, covering 1/3-1/2 nut, outer surface glabrous to sparsely puberulent, inner surface glabrous except for a few hairs around scar, scales acute, less than 4 mm, occasionally tuberculate, especially at base of cup, tips appressed; nut broadly ovoid to broadly ellipsoid, rarely oblong, 12-18.5 × 8-14 mm, occasionally with faint rings of pits at apex, glabrous or sparsely puberulent, scar diam. 3.5-8 mm.
Cotyledons	connate.
Terminal		buds grayish brown to reddish brown, ovoid to subfusiform, (2.5-)3-7 mm, scales on apical 1/2 distinctly ciliate.
2n	= 24.

	Quercus engelmannii	Quercus buckleyi
Phenology	Flowering in spring.	Flowering spring.
Habitat	Oak woodlands, margins of chaparral, arroyos, slopes and bajadas	Limestone ridges and slopes, creek bottoms, occasionally along larger streams
Elevation	50-1200 m (200-3900 ft)	150-500 m (500-1600 ft)
Distribution	CA; Mexico (Baja California) [WildflowerSearch map] [BONAP county map]	OK; TX [WildflowerSearch map] [BONAP county map]
Discussion	Quercus engelmannii is closely related to and possibly conspecific with Q. oblongifolia. The cups of Q. engelmannii are larger, deeper, and generally more tuberculate than those of Q. oblongifolia, and the scales are usually larger. Based on available samples, the nuts of Q. engelmannii are consistently larger than those of Q. oblongifolia, apparently with little, if any, overlap in diameter. Considerably more variation occurs within Q. engelmannii in leaf form, possibly reflecting introgression from other white oak species such as Q. cornelius-mulleri, Q. dumosa, and Q. durata (see treatment). On Catalina Island, Quercus engelmannii is known only from a small grove of trees. Putative hybrids between Q. engelmannii and Q. cornelius-mulleri are common in areas of contact between the two species in Riverside and San Diego counties in southern California. Such a population was the basis for Q. acutidens Torrey [Q. dumosa var. acutidens (Torrey) Wenzig]. Other names applied to those populations are Q. macdonaldii var. elegantula Greene and Q. dumosa var. elegantula (Greene) Jepson. Variable in leaf form and stature, those intermediates form extensive populations and are probably best disposed of under the name Q. ×acutidens. (Discussion copyrighted by Flora of North America; reprinted with permission.)	For many years the names Quercus texana, Q. rubra var. texana, and Q. shumardii var. texana were erroneously used for Q. buckleyi (L. J. Dorr and K. C. Nixon 1985). Quercus texana reportedly hybridizes with Q. marilandica (= Q. ×hastingsii Sargent). Quercus ×hastingsii may be derived from Q. marilandica var. ashei (D. M. Hunt 1989). Hybridization with Q. shumardii may also occur (L. J. Dorr and K. C. Nixon 1985). (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. Lobatae
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. 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	Q. acerifolia, Q. agrifolia, Q. ajoensis, Q. alba, Q. arizonica, Q. arkansana, Q. austrina, Q. berberidifolia, Q. bicolor, Q. boyntonii, 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. 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
Name authority	Greene: Ill. W. Amer. Oaks 1: 33, plate 17. (1889)	Nixon & Dorr: Taxon 34: 225. (1985)
Web links	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	WildflowerSearch iNaturalist (observations) USDA Plants Database LBJ Wildflower Center SEINet Plants of the World Online Encyclopedia of Life Wikipedia Google Image Search

Quercus buckleyi

Engelmann oak, Engelmann's oak

Buckley's oak, Texas oak, Texas red oak

Habit

Trees, subevergreen, to 10 m. Bark gray or whitish, closely furrowed.

Trees, deciduous, to 15 m. Bark gray and smooth or black and furrowed.

Twigs

light brown, 1-1.5 mm diam., densely or sparsely stellate-tomentose, soon glabrate.

grayish brown to red-brown, rarely somewhat yellowish or gray, 1.5-3 mm diam., glabrous.

Buds

reddish brown, subspheric to broadly ovoid, 1-2 mm, glabrous or basal scales pubescent;

stipules persistent about terminal buds.

Leaves

blade oblong to elliptic, occasionally lanceolate or ovate, (20-)30-60(-80) × (5-)10-20(-25) 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 blue-green or pale green, densely and loosely glandular-tomentose, quickly glabrate or persistently floccose, especially about base of midrib, at maturity strongly glaucous, adaxially gray-green or pale green, bluish green or glaucous.

blade circular or broadly elliptic to obovate, 55-100 × 51-112 mm, base cuneate to truncate, often inequilateral, margins with 7-9 lobes and 12-35 awns, lobes oblong to distally expanded, apex acute to acuminate;

surfaces abaxially light green or coppery green, glabrous or with small, axillary tufts of tomentum, adaxially shiny or glossy, glabrous, veins raised on both surfaces.

Acorns

solitary or paired, subsessile or on peduncle to 5-6 mm;

cup cup-shaped or shallowly cup-shaped, 8-10 mm deep × 10-15 mm wide, enclosing 1/3 nut, scales 1.5-3 mm wide, strongly and regularly tuberculate near base of cup, gray-pubescent;

nut light brown, ovoid or oblong, 15-25 × 12-14 mm, glabrate or puberulent about apex.

biennial;

cup goblet- to cup-shaped, rarely saucer-shaped, 5-11.5 mm high × 10-18 mm wide, covering 1/3-1/2 nut, outer surface glabrous to sparsely puberulent, inner surface glabrous except for a few hairs around scar, scales acute, less than 4 mm, occasionally tuberculate, especially at base of cup, tips appressed;

nut broadly ovoid to broadly ellipsoid, rarely oblong, 12-18.5 × 8-14 mm, occasionally with faint rings of pits at apex, glabrous or sparsely puberulent, scar diam. 3.5-8 mm.

Cotyledons

connate.

Terminal

buds grayish brown to reddish brown, ovoid to subfusiform, (2.5-)3-7 mm, scales on apical 1/2 distinctly ciliate.

= 24.

Quercus engelmannii

Quercus buckleyi

Phenology

Flowering in spring.

Flowering spring.

Habitat

Oak woodlands, margins of chaparral, arroyos, slopes and bajadas

Limestone ridges and slopes, creek bottoms, occasionally along larger streams

Elevation

50-1200 m (200-3900 ft)

150-500 m (500-1600 ft)

Distribution

CA; Mexico (Baja California)

[WildflowerSearch map]

[BONAP county map]

OK; TX

[WildflowerSearch map]

[BONAP county map]

Discussion

Quercus engelmannii is closely related to and possibly conspecific with Q. oblongifolia. The cups of Q. engelmannii are larger, deeper, and generally more tuberculate than those of Q. oblongifolia, and the scales are usually larger. Based on available samples, the nuts of Q. engelmannii are consistently larger than those of Q. oblongifolia, apparently with little, if any, overlap in diameter. Considerably more variation occurs within Q. engelmannii in leaf form, possibly reflecting introgression from other white oak species such as Q. cornelius-mulleri, Q. dumosa, and Q. durata (see treatment).

On Catalina Island, Quercus engelmannii is known only from a small grove of trees. Putative hybrids between Q. engelmannii and Q. cornelius-mulleri are common in areas of contact between the two species in Riverside and San Diego counties in southern California. Such a population was the basis for Q. acutidens Torrey [Q. dumosa var. acutidens (Torrey) Wenzig]. Other names applied to those populations are Q. macdonaldii var. elegantula Greene and Q. dumosa var. elegantula (Greene) Jepson. Variable in leaf form and stature, those intermediates form extensive populations and are probably best disposed of under the name Q. ×acutidens.

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

For many years the names Quercus texana, Q. rubra var. texana, and Q. shumardii var. texana were erroneously used for Q. buckleyi (L. J. Dorr and K. C. Nixon 1985).

Quercus texana reportedly hybridizes with Q. marilandica (= Q. ×hastingsii Sargent). Quercus ×hastingsii may be derived from Q. marilandica var. ashei (D. M. Hunt 1989). Hybridization with Q. shumardii may also occur (L. J. Dorr and K. C. Nixon 1985).

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

Source

FNA vol. 3.

Parent taxa

Fagaceae > Quercus > sect. Quercus

Fagaceae > Quercus > sect. Lobatae

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. 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

Q. acerifolia, Q. agrifolia, Q. ajoensis, Q. alba, Q. arizonica, Q. arkansana, Q. austrina, Q. berberidifolia, Q. bicolor, Q. boyntonii, 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. 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

Name authority

Greene: Ill. W. Amer. Oaks 1: 33, plate 17. (1889)

Nixon & Dorr: Taxon 34: 225. (1985)

Web links

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

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Flora of North America species comparison

Quercus engelmannii

Quercus buckleyi

Quercus engelmannii

Quercus buckleyi