FNA: Quercus cornelius-mulleri vs. Quercus gravesii

	Quercus cornelius-mulleri	Quercus gravesii
	desert scrub oak, muller oak, muller's oak	Chisos red oak, Graves oak
Habit	Shrubs, evergreen or subevergreen, densely branched, 1-2(-3) m. Bark gray, scaly.	Trees, deciduous, to 13 m. Bark black, roughly furrowed.
Twigs	gray, yellowish, or brownish, 1-1.5 mm diam., densely tomentulose, rarely glabrate.	light brown to dark reddish brown, (1-)1.5-2.5 mm diam., glabrous or glabrate.
Buds	dull brown, ovoid, 2.5-3 mm, glabrous except for margins of scales.
Leaves	blade strongly bicolored, ovate to oblong or narrowly obovate, 15-35 ×10-20 mm, rather thick and leathery, base cuneate or attenuate-rounded, margins entire or irregularly, shallowly toothed, teeth mucronate, rarely spinose, secondary veins 6-7 on each side, apex rounded or acute; surfaces abaxially whitish, densely covered with minute, compact, appressed, (8-)10-14(-16)-rayed stellate hairs less than 0.2 mm diam. (lateral fusion of rays visible under high magnification), without glandular seriate hairs, adaxially dull, light green, grayish, or yellowish green, with scattered, appressed-stellate hairs to 0.2 mm diam.	blade ovate to elliptic, 45-140 × 20-120 mm, base rounded (rarely subcordate) to obtuse or cuneate, margins with 3-5 acute lobes, 9-20 awns, apex broadly obtuse or acute to attenuate, occasionally falcate; surfaces abaxially light green or coppery green, glabrous with small axillary tufts of tomentum or pubescent along midrib and veins, adaxially shiny or glossy, glabrous except for scattered pubescence near base and along midrib.
Acorns	solitary or clustered, subsessile; cup deeply cup-shaped or turbinate, to 5-13 mm deep × 12-20 mm wide, scales whitish or cream, strongly tuberculate especially near base of cup; nut dark brown, fusiform or cylyndric, 20-30 × 10-30 mm.	biennial; cup turbinate or deeply cup-shaped, 4.5-8.5 mm high × 7.5-12 mm wide, covering 1/3-1/2 nut, outer surface glabrate, inner surface glabrous to pubescent on inner 2/3, scale tips appressed, less than 4 mm, acute; nut ovoid to ellipsoid, rarely subglobose or oblong, 9-16 × 5.5-11 mm, occasionally striate, glabrous to puberulent, especially at apex, scar diam. 3-6 mm.
Cotyledons	distinct.
Terminal		buds brown or reddish brown, ovoid or ellipsoid to subconic, 2-5 mm, glabrous or with tuft of hairs at apex.

	Quercus cornelius-mulleri	Quercus gravesii
Phenology	Flowering early spring.	Flowering spring.
Habitat	Open chaparral, pinyon and juniper woodlands, desert margins, often on loose granitic soils	Davis, Glass, and Chisos mountains
Elevation	1000-1800 m (3300-5900 ft)	above 1200 m (above 3900 ft)
Distribution	CA; Mexico (Baja California) [WildflowerSearch map] [BONAP county map]	TX; n Mexico [BONAP county map]
Discussion	Quercus cornelius-mulleri is easily distinguished from other California scrub oaks by the strongly bicolored leaves, dense minute tomentum of the abaxial leaf surface, and large acute acorns in deep tuberculate cups. Of greater difficulty are swarms of putative hybrids with Q. engelmannii, sometimes referred to as Q. ×acutidens. In Joshua Tree National Monument a lone tree and several shrubs appear to be hybrids and backcrosses between Quercus cornelius-mulleri and Q. lobata. This tree is the basis of Quercus ×munzii J. M. Tucker. (Discussion copyrighted by Flora of North America; reprinted with permission.)	Quercus gravesii reportedly hybridizes with Q. hypoleucoides. As noted above, forms of Q. gravesii and Q. robusta are easily confused and give the impression of belonging to a single morphologic continuum. Some authors have also used the name Quercus texana for Q. gravesii. (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. 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. 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. chisosensis, Q. shumardii var. microcarpa, Q. stellipila, Q. texana var. chisosensis, Q. texana var. stellapila
Name authority	Nixon & K. P. Steele: Madroño 28: 210. (1981)	Sudworth: Check List For. Trees U.S., 86. (1927)
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 gravesii

desert scrub oak, muller oak, muller's oak

Chisos red oak, Graves oak

Habit

Shrubs, evergreen or subevergreen, densely branched, 1-2(-3) m. Bark gray, scaly.

Trees, deciduous, to 13 m. Bark black, roughly furrowed.

Twigs

gray, yellowish, or brownish, 1-1.5 mm diam., densely tomentulose, rarely glabrate.

light brown to dark reddish brown, (1-)1.5-2.5 mm diam., glabrous or glabrate.

Buds

dull brown, ovoid, 2.5-3 mm, glabrous except for margins of scales.

Leaves

blade strongly bicolored, ovate to oblong or narrowly obovate, 15-35 ×10-20 mm, rather thick and leathery, base cuneate or attenuate-rounded, margins entire or irregularly, shallowly toothed, teeth mucronate, rarely spinose, secondary veins 6-7 on each side, apex rounded or acute;

surfaces abaxially whitish, densely covered with minute, compact, appressed, (8-)10-14(-16)-rayed stellate hairs less than 0.2 mm diam. (lateral fusion of rays visible under high magnification), without glandular seriate hairs, adaxially dull, light green, grayish, or yellowish green, with scattered, appressed-stellate hairs to 0.2 mm diam.

blade ovate to elliptic, 45-140 × 20-120 mm, base rounded (rarely subcordate) to obtuse or cuneate, margins with 3-5 acute lobes, 9-20 awns, apex broadly obtuse or acute to attenuate, occasionally falcate;

surfaces abaxially light green or coppery green, glabrous with small axillary tufts of tomentum or pubescent along midrib and veins, adaxially shiny or glossy, glabrous except for scattered pubescence near base and along midrib.

Acorns

solitary or clustered, subsessile;

cup deeply cup-shaped or turbinate, to 5-13 mm deep × 12-20 mm wide, scales whitish or cream, strongly tuberculate especially near base of cup;

nut dark brown, fusiform or cylyndric, 20-30 × 10-30 mm.

biennial;

cup turbinate or deeply cup-shaped, 4.5-8.5 mm high × 7.5-12 mm wide, covering 1/3-1/2 nut, outer surface glabrate, inner surface glabrous to pubescent on inner 2/3, scale tips appressed, less than 4 mm, acute;

nut ovoid to ellipsoid, rarely subglobose or oblong, 9-16 × 5.5-11 mm, occasionally striate, glabrous to puberulent, especially at apex, scar diam. 3-6 mm.

Cotyledons

distinct.

Terminal

buds brown or reddish brown, ovoid or ellipsoid to subconic, 2-5 mm, glabrous or with tuft of hairs at apex.

Quercus cornelius-mulleri

Quercus gravesii

Phenology

Flowering early spring.

Flowering spring.

Habitat

Open chaparral, pinyon and juniper woodlands, desert margins, often on loose granitic soils

Davis, Glass, and Chisos mountains

Elevation

1000-1800 m (3300-5900 ft)

above 1200 m (above 3900 ft)

Distribution

CA; Mexico (Baja California)

[WildflowerSearch map]

[BONAP county map]

TX; n Mexico

[BONAP county map]

Discussion

Quercus cornelius-mulleri is easily distinguished from other California scrub oaks by the strongly bicolored leaves, dense minute tomentum of the abaxial leaf surface, and large acute acorns in deep tuberculate cups. Of greater difficulty are swarms of putative hybrids with Q. engelmannii, sometimes referred to as Q. ×acutidens.

In Joshua Tree National Monument a lone tree and several shrubs appear to be hybrids and backcrosses between Quercus cornelius-mulleri and Q. lobata. This tree is the basis of Quercus ×munzii J. M. Tucker.

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

Quercus gravesii reportedly hybridizes with Q. hypoleucoides. As noted above, forms of Q. gravesii and Q. robusta are easily confused and give the impression of belonging to a single morphologic continuum.

Some authors have also used the name Quercus texana for Q. gravesii.

(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. 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. 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. chisosensis, Q. shumardii var. microcarpa, Q. stellipila, Q. texana var. chisosensis, Q. texana var. stellapila

Name authority

Nixon & K. P. Steele: Madroño 28: 210. (1981)

Sudworth: Check List For. Trees U.S., 86. (1927)

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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Quercus cornelius-mulleri

Quercus gravesii

Quercus cornelius-mulleri

Quercus gravesii