FNA: Quercus arizonica vs. Quercus dumosa

	Quercus arizonica	Quercus dumosa
	Arizona oak, Arizona white oak	coastal sage scrub oak, Nuttall's scrub oak, scrub oak
Habit	Trees, evergreen or subevergreen, small to moderate-sized trees, rarely to 18 m. Bark scaly.	Shrubs, subevergreen, 1-2(-2.5) m, dense, divaricately branching, leaves brittle, often falling when branches disturbed.
Bark		smooth when young, eventually scaly.
Twigs	yellowish, 1.5-2.5 mm diam., persistently felty-tomentose, eventually dingy gray.	reddish or grayish, 1-1.5(-2) mm diam., glabrous or sparsely stellate-pubescent, soon glabrate.
Buds	dull russet-brown, ovoid, distally subacute or rounded, 3 mm, sparsely pubescent or glabrate.	reddish brown, globose or ovoid, 1-2 mm, glabrous, rarely puberulent near apex.
Leaves	blade elliptic or oblong to narrowly obovate or oblanceolate, planar or moderately convex, to (30-)40-80(-90) × 15-30 mm, thick and leathery, usually stiff, base cordate or rounded and weakly cordate, margins entire or coarsely toothed especially near apex, cartilaginously revolute, teeth mucronate-tipped, obscure or prominent, secondary veins ca. 7-11 on each side, branching, passing into teeth when present, apex acute to usually obtuse or broadly rounded; surfaces abaxially dull, sparsely pubescent or subtomentose with curly branched hairs, reticulate from prominent, raised secondary veins, usually glaucous where exposed, adaxially dark or bluish green, moderately lustrous, sparsely and minutely stellate-pubescent, secondary veins slightly raised or prominent within depressions or impressed.	blade undulate or strongly to moderately cupped, occasionally subplanar, 10-20(-25) × 6-15(-20) mm, base cordate or angular-cordate, margins irregularly spinose-toothed or shallowly lobed, rarely entire, often somewhat revolute, secondary veins 3-5(-6) on each side, irregularly branched, apex rounded or spinose-acute; surfaces abaxially sparsely to densely covered with erect, curly, (2-)4(-6)-rayed fasciculate hairs to 0.5 mm, felty to touch in young leaves, adaxially glossy green, glabrate or with scattered stellate hairs, secondary veins somewhat impressed, puberulent.
Acorns	solitary or paired, subsessile, occasionally on peduncle to 15 mm; cup hemispheric or cup-shaped, 5-10(-15) mm deep × 10-15 mm wide, enclosing ca. 1/2 nut, base rounded, margin rather coarse, scales cream to brown, broadly ovate, evenly and strongly tuberculate, tomentose, tips closely appressed; nut light brown, ovoid or oblong, 8-12 mm, nearly glabrous.	solitary or paired, subsessile; cup reddish, deeply cup-shaped, 5-8 mm deep × 8-15 mm wide, enclosing 1/3 nut or less, scales long-acute, moderately or scarcely tuberculate at base; nut fusiform or subcylindric, 10-20(-30) × 5-10(-12) mm, apex acute.
Cotyledons	connate.	distinct.

	Quercus arizonica	Quercus dumosa
Phenology	Flowering spring.	Flowering spring.
Habitat	Oak and pinyon woodlands, margins of chaparral, arroyos	Open chaparral, coastal sage scrub
Elevation	1300-2500(-3000) m (4300-8200(-9800) ft)	0-300 m (0-1000 ft)
Distribution	AZ; NM; TX; Mexico (Chihuahua, Coahuila, Durango, and Sonora) [WildflowerSearch map] [BONAP county map]	CA; Mexico (Baja California) [WildflowerSearch map] [BONAP county map]
Discussion	Some of the specimens previously referred to Quercus endemica by C. H. Muller belong here instead. Putative hybrids between Quercus arizonica and Q. grisea (= Q. ×organensis Trelease) are problematic in local areas of contact from southeastern Arizona to western Texas. These intermediates tend to have narrower leaves than Q. arizonica, with moderately reticulate patterns of venation, and more densely hairy leaves. Quercus arizonica and Q. grisea are amply distinct elsewhere, including large areas in northern Mexico, and they appear to be more closely related to other species than to one another (e.g., Q. arizonica with Q. oblongifolia and Q. laeta Liebmann, and Q. grisea with Q. mohriana and Q. microphylla Née). Thus, Q. arizonica and Q. grisea are best treated as distinct species that hybridize, and not as conspecific populations. (Discussion copyrighted by Flora of North America; reprinted with permission.)	Of conservation concern. The name Quercus dumosa has been applied to virtually all scrub oaks in the white oak group of central and southern California and adjacent Baja California. Through the years, and following independent studies by various authors, the concept of this species has gradually narrowed from the original, which included plants here segregated as Q. turbinella, Q. john-tuckeri, Q. cornelius-mulleri, Q. berberidifolia, and Q. pacifica. In degree and constancy, the differences among these species are similar to those separating other commonly recognized tree species of the western United States. The majority of populations referred to Q. dumosa in recent treatments are now included in Q. berberidifolia (see treatment). All of the scrub oaks have a striking superficial similarity because of their shrubby habit and small, often spiny leaves; they differ dramatically in leaf and twig vestiture and acorn form. The concept of Q. dumosa presented here limits it to populations of scraggly shrubs with short petioles, cordate leaf bases, erect curly trichomes on the abaxial leaf surface, and narrow acute acorns that occur at low elevations almost always within sight of the ocean. Because these locations are typically prime real estate, the species, which probably never was common, is highly at risk. It rarely comes into contact with other white oaks because of its low elevation and dry habitat preference; putative hybrids are known, however, with Q. engelmannii and Q. lobata. Some populations of Q. berberidifolia from higher elevations near populations of Q. dumosa show signs of introgression. Named hybrids include Quercus ×kinselae (C. H. Muller) Nixon & C. H. Muller (= Q. dumosa Nuttall × Q. lobata Née) and Q. dumosa Nuttall var. kinselae C. H. Muller (= Q. dumosa × Q. engelmannii). The Luisenos used gall nuts from Quercus dumosa medicinally for sores and wounds and as an astringent (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	Q. acerifolia, Q. agrifolia, Q. ajoensis, Q. alba, 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. 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. 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. sacame
Name authority	Sargent: Gard. & Forest 8: 92. (1895)	Nuttall: N. Amer. Sylv. 1: 7. (1842)
Web links	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 dumosa

Arizona oak, Arizona white oak

coastal sage scrub oak, Nuttall's scrub oak, scrub oak

Habit

Trees, evergreen or subevergreen, small to moderate-sized trees, rarely to 18 m. Bark scaly.

Shrubs, subevergreen, 1-2(-2.5) m, dense, divaricately branching, leaves brittle, often falling when branches disturbed.

Bark

smooth when young, eventually scaly.

Twigs

yellowish, 1.5-2.5 mm diam., persistently felty-tomentose, eventually dingy gray.

reddish or grayish, 1-1.5(-2) mm diam., glabrous or sparsely stellate-pubescent, soon glabrate.

Buds

dull russet-brown, ovoid, distally subacute or rounded, 3 mm, sparsely pubescent or glabrate.

reddish brown, globose or ovoid, 1-2 mm, glabrous, rarely puberulent near apex.

Leaves

blade elliptic or oblong to narrowly obovate or oblanceolate, planar or moderately convex, to (30-)40-80(-90) × 15-30 mm, thick and leathery, usually stiff, base cordate or rounded and weakly cordate, margins entire or coarsely toothed especially near apex, cartilaginously revolute, teeth mucronate-tipped, obscure or prominent, secondary veins ca. 7-11 on each side, branching, passing into teeth when present, apex acute to usually obtuse or broadly rounded;

surfaces abaxially dull, sparsely pubescent or subtomentose with curly branched hairs, reticulate from prominent, raised secondary veins, usually glaucous where exposed, adaxially dark or bluish green, moderately lustrous, sparsely and minutely stellate-pubescent, secondary veins slightly raised or prominent within depressions or impressed.

blade undulate or strongly to moderately cupped, occasionally subplanar, 10-20(-25) × 6-15(-20) mm, base cordate or angular-cordate, margins irregularly spinose-toothed or shallowly lobed, rarely entire, often somewhat revolute, secondary veins 3-5(-6) on each side, irregularly branched, apex rounded or spinose-acute;

surfaces abaxially sparsely to densely covered with erect, curly, (2-)4(-6)-rayed fasciculate hairs to 0.5 mm, felty to touch in young leaves, adaxially glossy green, glabrate or with scattered stellate hairs, secondary veins somewhat impressed, puberulent.

Acorns

solitary or paired, subsessile, occasionally on peduncle to 15 mm;

cup hemispheric or cup-shaped, 5-10(-15) mm deep × 10-15 mm wide, enclosing ca. 1/2 nut, base rounded, margin rather coarse, scales cream to brown, broadly ovate, evenly and strongly tuberculate, tomentose, tips closely appressed;

nut light brown, ovoid or oblong, 8-12 mm, nearly glabrous.

solitary or paired, subsessile;

cup reddish, deeply cup-shaped, 5-8 mm deep × 8-15 mm wide, enclosing 1/3 nut or less, scales long-acute, moderately or scarcely tuberculate at base;

nut fusiform or subcylindric, 10-20(-30) × 5-10(-12) mm, apex acute.

Cotyledons

connate.

distinct.

Quercus arizonica

Quercus dumosa

Phenology

Flowering spring.

Habitat

Oak and pinyon woodlands, margins of chaparral, arroyos

Open chaparral, coastal sage scrub

Elevation

1300-2500(-3000) m (4300-8200(-9800) ft)

0-300 m (0-1000 ft)

Distribution

AZ; NM; TX; Mexico (Chihuahua, Coahuila, Durango, and Sonora)

[WildflowerSearch map]

[BONAP county map]

CA; Mexico (Baja California)

[WildflowerSearch map]

[BONAP county map]

Discussion

Some of the specimens previously referred to Quercus endemica by C. H. Muller belong here instead.

Putative hybrids between Quercus arizonica and Q. grisea (= Q. ×organensis Trelease) are problematic in local areas of contact from southeastern Arizona to western Texas. These intermediates tend to have narrower leaves than Q. arizonica, with moderately reticulate patterns of venation, and more densely hairy leaves. Quercus arizonica and Q. grisea are amply distinct elsewhere, including large areas in northern Mexico, and they appear to be more closely related to other species than to one another (e.g., Q. arizonica with Q. oblongifolia and Q. laeta Liebmann, and Q. grisea with Q. mohriana and Q. microphylla Née). Thus, Q. arizonica and Q. grisea are best treated as distinct species that hybridize, and not as conspecific populations.

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

Of conservation concern.

The name Quercus dumosa has been applied to virtually all scrub oaks in the white oak group of central and southern California and adjacent Baja California. Through the years, and following independent studies by various authors, the concept of this species has gradually narrowed from the original, which included plants here segregated as Q. turbinella, Q. john-tuckeri, Q. cornelius-mulleri, Q. berberidifolia, and Q. pacifica. In degree and constancy, the differences among these species are similar to those separating other commonly recognized tree species of the western United States. The majority of populations referred to Q. dumosa in recent treatments are now included in Q. berberidifolia (see treatment). All of the scrub oaks have a striking superficial similarity because of their shrubby habit and small, often spiny leaves; they differ dramatically in leaf and twig vestiture and acorn form. The concept of Q. dumosa presented here limits it to populations of scraggly shrubs with short petioles, cordate leaf bases, erect curly trichomes on the abaxial leaf surface, and narrow acute acorns that occur at low elevations almost always within sight of the ocean. Because these locations are typically prime real estate, the species, which probably never was common, is highly at risk. It rarely comes into contact with other white oaks because of its low elevation and dry habitat preference; putative hybrids are known, however, with Q. engelmannii and Q. lobata. Some populations of Q. berberidifolia from higher elevations near populations of Q. dumosa show signs of introgression.

Named hybrids include Quercus ×kinselae (C. H. Muller) Nixon & C. H. Muller (= Q. dumosa Nuttall × Q. lobata Née) and Q. dumosa Nuttall var. kinselae C. H. Muller (= Q. dumosa × Q. engelmannii).

The Luisenos used gall nuts from Quercus dumosa medicinally for sores and wounds and as an astringent (D. E. Moerman 1986).

(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. 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. 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. 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. sacame

Name authority

Sargent: Gard. & Forest 8: 92. (1895)

Nuttall: N. Amer. Sylv. 1: 7. (1842)

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 arizonica

Quercus dumosa

Quercus arizonica

Quercus dumosa