FNA: Quercus arizonica vs. Quercus muehlenbergii

	Quercus arizonica	Quercus muehlenbergii
	Arizona oak, Arizona white oak	Chinkapin oak, chinquapin oak, yellow chestnut oak
Habit	Trees, evergreen or subevergreen, small to moderate-sized trees, rarely to 18 m. Bark scaly.	Trees, deciduous, moderate to large, to 30 m, occasionally large shrubs (ca. 3 m) on drier sites.
Bark		gray, thin, flaky to papery.
Twigs	yellowish, 1.5-2.5 mm diam., persistently felty-tomentose, eventually dingy gray.	brownish, 1.5-3(-4) mm diam., sparsely fine-pubescent, soon becoming glabrate, graying in 2d year.
Buds	dull russet-brown, ovoid, distally subacute or rounded, 3 mm, sparsely pubescent or glabrate.	brown to red-brown, subrotund to broadly ovoid, 20-40 × (10-)15-25 mm, apex rounded, very sparsely pubescent.
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 usually obovate, sometimes lanceolate to oblanceolate, (32-)50-150(-210) × (10-)40-80(-106) mm, leathery, base truncate to cuneate, margins regularly undulate, toothed or shallow-lobed, teeth or lobes rounded, or acute-acuminate, often strongly antrorse, secondary veins usually (9-)10-14(-16) on each side, ± parallel, apex short-acute to acuminate or apiculate; surfaces abaxially glaucous or light green, appearing glabrate but with scattered or crowded minute, appressed, symmetric, 6-10-rayed stellate hairs, adaxially lustrous dark green, glabrate.
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.	1-2, subsessile or on axillary peduncle to 8 mm; cup hemispheric or shallowly cupped, 4-12 mm deep × 8-22 mm wide, enclosing 1/4-1/2 nut, base rounded, margin usually thin, scales closely appressed, moderately to prominently tuberculate, uniformly short gray-pubescent; nut light brown, oblong to ovoid, (13-)15-20(-28) × 10-13(-16) mm.
Cotyledons	connate.	distinct.
2n		= 24.

	Quercus arizonica	Quercus muehlenbergii
Phenology	Flowering spring.	Flowering late winter–spring.
Habitat	Oak and pinyon woodlands, margins of chaparral, arroyos	Mixed deciduous forest, woodlands and thickets, sometimes restricted to n slopes and riparian habitats in w parts of range, limestone and calcareous soils, rarely on other substrates
Elevation	1300-2500(-3000) m (4300-8200(-9800) ft)	0-2300 m (0-7500 ft)
Distribution	AZ; NM; TX; Mexico (Chihuahua, Coahuila, Durango, and Sonora) [WildflowerSearch map] [BONAP county map]	AL; AR; CT; FL; GA; IA; IL; IN; KS; KY; LA; MA; MD; MI; MN; MO; MS; NC; NE; NJ; NM; NY; OH; OK; PA; SC; TN; TX; VA; VT; WI; WV; ON; Mexico (Coahuila, Nuevo León, Hidalgo, and Tamaulipas) [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.)	Shrubby forms of Quercus muhlenbergii are difficult to distinguish from Quercus prinoides, but Q. muhlenbergii does not spread clonally or produce acorns on small shrubs as does Q. prinoides. The edaphic preferences of these two species are distinctive, with Q. muhlenbergii never far from limestone substrates and Q. prinoides occurring mostly on dry shales and deep sands. Populations of Q. muhlenbergii from the southwest part of its range, on the Edwards Plateau of Texas and westward, sometimes are segregated as Q. brayi Small, but the variation appears to be clinal with inconsistent differences. Distributed from Hidalgo, Mexico to Maine, Q. muhlenbergii is one of the most widespread species of temperate North American trees. The Delaware-Ontario prepared infusions from the bark of Quercus muhlenbergii to stop vomiting (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. 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. 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	Q. acuminata, Q. brayi, Q. prinus var. acuminata
Name authority	Sargent: Gard. & Forest 8: 92. (1895)	Engelmann: Trans. Acad. Sci. St. Louis 3: 391. (1887)
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 Web sites: Go Botany, IL Wildflowers, KS Wildflowers, LA Plants, MD Biodiversity, MI Flora, MN Wildflowers, MO Plants WildflowerSearch iNaturalist (observations) USDA Plants Database LBJ Wildflower Center SEINet Plants of the World Online Encyclopedia of Life Wikipedia Google Image Search

Quercus muehlenbergii

Arizona oak, Arizona white oak

Chinkapin oak, chinquapin oak, yellow chestnut oak

Habit

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

Trees, deciduous, moderate to large, to 30 m, occasionally large shrubs (ca. 3 m) on drier sites.

Bark

gray, thin, flaky to papery.

Twigs

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

brownish, 1.5-3(-4) mm diam., sparsely fine-pubescent, soon becoming glabrate, graying in 2d year.

Buds

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

brown to red-brown, subrotund to broadly ovoid, 20-40 × (10-)15-25 mm, apex rounded, very sparsely pubescent.

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 usually obovate, sometimes lanceolate to oblanceolate, (32-)50-150(-210) × (10-)40-80(-106) mm, leathery, base truncate to cuneate, margins regularly undulate, toothed or shallow-lobed, teeth or lobes rounded, or acute-acuminate, often strongly antrorse, secondary veins usually (9-)10-14(-16) on each side, ± parallel, apex short-acute to acuminate or apiculate;

surfaces abaxially glaucous or light green, appearing glabrate but with scattered or crowded minute, appressed, symmetric, 6-10-rayed stellate hairs, adaxially lustrous dark green, glabrate.

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.

1-2, subsessile or on axillary peduncle to 8 mm;

cup hemispheric or shallowly cupped, 4-12 mm deep × 8-22 mm wide, enclosing 1/4-1/2 nut, base rounded, margin usually thin, scales closely appressed, moderately to prominently tuberculate, uniformly short gray-pubescent;

nut light brown, oblong to ovoid, (13-)15-20(-28) × 10-13(-16) mm.

Cotyledons

connate.

distinct.

= 24.

Quercus arizonica

Quercus muehlenbergii

Phenology

Flowering spring.

Flowering late winter–spring.

Habitat

Oak and pinyon woodlands, margins of chaparral, arroyos

Mixed deciduous forest, woodlands and thickets, sometimes restricted to n slopes and riparian habitats in w parts of range, limestone and calcareous soils, rarely on other substrates

Elevation

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

0-2300 m (0-7500 ft)

Distribution

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

[WildflowerSearch map]

[BONAP county map]

AL; AR; CT; FL; GA; IA; IL; IN; KS; KY; LA; MA; MD; MI; MN; MO; MS; NC; NE; NJ; NM; NY; OH; OK; PA; SC; TN; TX; VA; VT; WI; WV; ON; Mexico (Coahuila, Nuevo León, Hidalgo, and Tamaulipas)

[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.)

Shrubby forms of Quercus muhlenbergii are difficult to distinguish from Quercus prinoides, but Q. muhlenbergii does not spread clonally or produce acorns on small shrubs as does Q. prinoides. The edaphic preferences of these two species are distinctive, with Q. muhlenbergii never far from limestone substrates and Q. prinoides occurring mostly on dry shales and deep sands. Populations of Q. muhlenbergii from the southwest part of its range, on the Edwards Plateau of Texas and westward, sometimes are segregated as Q. brayi Small, but the variation appears to be clinal with inconsistent differences. Distributed from Hidalgo, Mexico to Maine, Q. muhlenbergii is one of the most widespread species of temperate North American trees.

The Delaware-Ontario prepared infusions from the bark of Quercus muhlenbergii to stop vomiting (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. 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. 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

Q. acuminata, Q. brayi, Q. prinus var. acuminata

Name authority

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

Engelmann: Trans. Acad. Sci. St. Louis 3: 391. (1887)

Web links

Local Web sites: Go Botany, IL Wildflowers, KS Wildflowers, LA Plants, MD Biodiversity, MI Flora, MN Wildflowers, MO Plants
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).

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Flora of North America species comparison

Quercus arizonica

Quercus muehlenbergii

Quercus arizonica

Quercus muehlenbergii