FNA: Quercus engelmannii vs. Quercus pungens

	Quercus engelmannii	Quercus pungens
	Engelmann oak, Engelmann's oak	pungent oak, sandpaper oak
Habit	Trees, subevergreen, to 10 m. Bark gray or whitish, closely furrowed.	Shrubs or moderate-sized trees, evergreen or subevergreen.
Bark		light brown, papery.
Twigs	light brown, 1-1.5 mm diam., densely or sparsely stellate-tomentose, soon glabrate.	gray, 1-2 mm diam., short velvety-tomentose, glabrate with age.
Buds	reddish brown, subspheric to broadly ovoid, 1-2 mm, glabrous or basal scales pubescent; stipules persistent about terminal buds.	dark red-brown, ca. 2 mm, sparsely pubescent.
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 elliptic to oblong, 10-40(-90) × 10-20(-40) mm, rather thick, leathery, stiff, base rounded or minutely cordate, very rarely cuneate, margins regularly undulate-crisped, not revolute, coarsely toothed or incised with acute teeth or spinose lobes, secondary veins 5-8(-14) on each side, usually branched before passing into teeth, apex acute or obtuse, rarely rounded, spine-tipped; surfaces abaxially canescent, usually densely stellate-pubescent, and mixed with stiff, harsh, stellate hairs, often sandpapery to touch, rarely glabrate, adaxially yellowish green, glossy, usually rough and sandpapery because of minute, persistent hair bases, rarely glabrate.
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.	subsessile or on peduncle to 3 mm; cup shallowly to deeply cup-shaped or turbinate, to 8 mm deep × 13 mm wide, covering ca. 1/4 nut, margin thin, scales reddish brown, moderately tuberculate or keeled, densely gray-tomentose; nut light brown, broadly ovoid to subcylindric, to 10 × 10 mm, apex rounded to subacute, glabrous.
Cotyledons	connate.	distinct.
2n	= 24.

	Quercus engelmannii	Quercus pungens
Phenology	Flowering in spring.	Flowering spring.
Habitat	Oak woodlands, margins of chaparral, arroyos, slopes and bajadas	On dry limestone or igneous slopes, usually in oak, pinyon, and juniper woodlands, chaparral, and sometimes descending into desert vegetation
Elevation	50-1200 m (200-3900 ft)	800-2000 m (2600-6600 ft)
Distribution	CA; Mexico (Baja California) [WildflowerSearch map] [BONAP county map]	AZ; NM; TX; Mexico (Chihuahua and Coahuila) [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.)	Numerous populations appear to be hybrid swarms between Quercus pungens and Q. vaseyana, which is sometimes treated as a variety of Q. pungens. No other evidence for a close relationship exists for these two species, and such a treatment risks erecting a polyphyletic assemblage. To the west and south within the range of Q. pungens no indication of introgression exists, and the two species are strikingly different and easily separable. I interpret the contact as secondary. (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. 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. 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. 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. undulata var. pungens
Name authority	Greene: Ill. W. Amer. Oaks 1: 33, plate 17. (1889)	Liebmann: Overs. Kongel. Danske Vidensk. Selsk. Forh. Medlemmers Arbeider 1854: 171. 185: not Q. pungens Gandoger 1890
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 pungens

Engelmann oak, Engelmann's oak

pungent oak, sandpaper oak

Habit

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

Shrubs or moderate-sized trees, evergreen or subevergreen.

Bark

light brown, papery.

Twigs

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

gray, 1-2 mm diam., short velvety-tomentose, glabrate with age.

Buds

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

stipules persistent about terminal buds.

dark red-brown, ca. 2 mm, sparsely pubescent.

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 elliptic to oblong, 10-40(-90) × 10-20(-40) mm, rather thick, leathery, stiff, base rounded or minutely cordate, very rarely cuneate, margins regularly undulate-crisped, not revolute, coarsely toothed or incised with acute teeth or spinose lobes, secondary veins 5-8(-14) on each side, usually branched before passing into teeth, apex acute or obtuse, rarely rounded, spine-tipped;

surfaces abaxially canescent, usually densely stellate-pubescent, and mixed with stiff, harsh, stellate hairs, often sandpapery to touch, rarely glabrate, adaxially yellowish green, glossy, usually rough and sandpapery because of minute, persistent hair bases, rarely glabrate.

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.

subsessile or on peduncle to 3 mm;

cup shallowly to deeply cup-shaped or turbinate, to 8 mm deep × 13 mm wide, covering ca. 1/4 nut, margin thin, scales reddish brown, moderately tuberculate or keeled, densely gray-tomentose;

nut light brown, broadly ovoid to subcylindric, to 10 × 10 mm, apex rounded to subacute, glabrous.

Cotyledons

connate.

distinct.

= 24.

Quercus engelmannii

Quercus pungens

Phenology

Flowering in spring.

Flowering spring.

Habitat

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

On dry limestone or igneous slopes, usually in oak, pinyon, and juniper woodlands, chaparral, and sometimes descending into desert vegetation

Elevation

50-1200 m (200-3900 ft)

800-2000 m (2600-6600 ft)

Distribution

CA; Mexico (Baja California)

[WildflowerSearch map]

[BONAP county map]

AZ; NM; TX; Mexico (Chihuahua and Coahuila)

[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.)

Numerous populations appear to be hybrid swarms between Quercus pungens and Q. vaseyana, which is sometimes treated as a variety of Q. pungens. No other evidence for a close relationship exists for these two species, and such a treatment risks erecting a polyphyletic assemblage. To the west and south within the range of Q. pungens no indication of introgression exists, and the two species are strikingly different and easily separable. I interpret the contact as secondary.

(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. 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. 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. 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. undulata var. pungens

Name authority

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

Liebmann: Overs. Kongel. Danske Vidensk. Selsk. Forh. Medlemmers Arbeider 1854: 171. 185: not Q. pungens Gandoger 1890

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

The species comparison tool is brought to you by:

Flora of North America species comparison

Quercus engelmannii

Quercus pungens

Quercus engelmannii

Quercus pungens