FNA: Quercus dumosa vs. Quercus chihuahuensis

	Quercus dumosa	Quercus chihuahuensis
	coastal sage scrub oak, Nuttall's scrub oak, scrub oak	Chihuahua oak, Chihuahuan oak, felt oak
Habit	Shrubs, subevergreen, 1-2(-2.5) m, dense, divaricately branching, leaves brittle, often falling when branches disturbed.	Shrubs or trees, deciduous, to 10 m. Bark gray, furrowed, checkered, or scaly.
Bark	smooth when young, eventually scaly.
Twigs	reddish or grayish, 1-1.5(-2) mm diam., glabrous or sparsely stellate-pubescent, soon glabrate.	gray, 2-3(-4) mm diam., densely tomentose.
Buds	reddish brown, globose or ovoid, 1-2 mm, glabrous, rarely puberulent near apex.	reddish brown, broadly ovoid, distally rounded, 2-2.5 mm, densely yellowish pubescent; scales gray-puberulent; stipules persistent, 1-4, subulate, pubescent, at base of terminal buds.
Leaves	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.	blade elliptic or oblong to ovate or obovate, (25-)40-50(-85) × (18-)20-30(-50) mm, base rounded or shallowly cordate, margins entire or toothed to sublobate, secondary veins 8 to 10 on each side, somewhat branching, apex broadly rounded to acute; surfaces abaxially yellowish or grayish, densely stellate with velvety hairs, adaxially green, sparsely soft-pubescent with prominent, spreading, stellate hairs, felty to touch, secondary veins somewhat prominent on both surfaces, even under dense tomentum.
Acorns	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.	1-3 on tomentose peduncle 15-35(-60) mm; cup hemispheric, 7-10 mm deep × 10-15 mm wide, enclosing 1/2 nut, scales proximally thickened, distally appressed, densely gray-puberulent, tips reddish, ultimately glabrate; nut ovoid, 14-18 × 10-12 mm, puberulent, eventually glabrate.
Cotyledons	distinct.	connate.

	Quercus dumosa	Quercus chihuahuensis
Phenology	Flowering spring.	Flowering spring.
Habitat	Open chaparral, coastal sage scrub	Oak and pinyon-juniper woodlands, grassy hills, sometimes extending into dry thorn scrub and bursera woodland (Mexico)
Elevation	0-300 m (0-1000 ft)	400-2000 m (1300-6600 ft)
Distribution	CA; Mexico (Baja California) [WildflowerSearch map] [BONAP county map]	TX; Mexico (Chihuahua, Sonora, Zacatecas, and San Luis Potosí) [WildflowerSearch map] [BONAP county map]
Discussion	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.)	Quercus chihuahuensis is a distinctive species throughout its range, mostly in dry montane western Mexico; it occurs in the United States only as putative hybrids with Q. grisea (the Eagle and Quitman mountains) and Q. arizonica (Hueco Tanks) in Texas. (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. 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. 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
Synonyms		Q. infralutea, Q. jaliscensis, Q. santaclarensis
Name authority	Nuttall: N. Amer. Sylv. 1: 7. (1842)	Trelease: Mem. Natl. Acad. Sci. 20: 85. (1924)
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 chihuahuensis

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

Chihuahua oak, Chihuahuan oak, felt oak

Habit

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

Shrubs or trees, deciduous, to 10 m. Bark gray, furrowed, checkered, or scaly.

Bark

smooth when young, eventually scaly.

Twigs

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

gray, 2-3(-4) mm diam., densely tomentose.

Buds

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

reddish brown, broadly ovoid, distally rounded, 2-2.5 mm, densely yellowish pubescent;

scales gray-puberulent;

stipules persistent, 1-4, subulate, pubescent, at base of terminal buds.

Leaves

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.

blade elliptic or oblong to ovate or obovate, (25-)40-50(-85) × (18-)20-30(-50) mm, base rounded or shallowly cordate, margins entire or toothed to sublobate, secondary veins 8 to 10 on each side, somewhat branching, apex broadly rounded to acute;

surfaces abaxially yellowish or grayish, densely stellate with velvety hairs, adaxially green, sparsely soft-pubescent with prominent, spreading, stellate hairs, felty to touch, secondary veins somewhat prominent on both surfaces, even under dense tomentum.

Acorns

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.

1-3 on tomentose peduncle 15-35(-60) mm;

cup hemispheric, 7-10 mm deep × 10-15 mm wide, enclosing 1/2 nut, scales proximally thickened, distally appressed, densely gray-puberulent, tips reddish, ultimately glabrate;

nut ovoid, 14-18 × 10-12 mm, puberulent, eventually glabrate.

Cotyledons

distinct.

connate.

Quercus dumosa

Quercus chihuahuensis

Phenology

Flowering spring.

Habitat

Open chaparral, coastal sage scrub

Oak and pinyon-juniper woodlands, grassy hills, sometimes extending into dry thorn scrub and bursera woodland (Mexico)

Elevation

0-300 m (0-1000 ft)

400-2000 m (1300-6600 ft)

Distribution

CA; Mexico (Baja California)

[WildflowerSearch map]

[BONAP county map]

TX; Mexico (Chihuahua, Sonora, Zacatecas, and San Luis Potosí)

[WildflowerSearch map]

[BONAP county map]

Discussion

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.)

Quercus chihuahuensis is a distinctive species throughout its range, mostly in dry montane western Mexico; it occurs in the United States only as putative hybrids with Q. grisea (the Eagle and Quitman mountains) and Q. arizonica (Hueco Tanks) in Texas.

(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. 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. 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

Synonyms

Q. infralutea, Q. jaliscensis, Q. santaclarensis

Name authority

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

Trelease: Mem. Natl. Acad. Sci. 20: 85. (1924)

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 dumosa

Quercus chihuahuensis

Quercus dumosa

Quercus chihuahuensis