FNA: Quercus cornelius-mulleri vs. Quercus myrtifolia

	Quercus cornelius-mulleri	Quercus myrtifolia
	desert scrub oak, muller oak, muller's oak	myrtle oak
Habit	Shrubs, evergreen or subevergreen, densely branched, 1-2(-3) m. Bark gray, scaly.	Trees or shrubs, evergreen, to 12 m. Bark gray and smooth distally, dark and shallowly furrowed near base.
Twigs	gray, yellowish, or brownish, 1-1.5 mm diam., densely tomentulose, rarely glabrate.	dark red-brown, 1-2.5(-3) mm diam., persistently pubescent, rarely almost glabrous.
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 elliptic to narrowly or broadly obovate, occasionally spatulate, 15-50(-70) × 10-25(-35) mm, base cuneate to rounded, margins entire, somewhat revolute, with 1-4 awns, apex obtuse or rounded; surfaces abaxially glabrous except for axillary tufts of tomentum, occasionally yellow-scurfy, adaxial surface planar, glabrous.
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 saucer-shaped to shallowly goblet-shaped, 4-7 mm high × 8.5-14.5 mm wide, covering 1/4-1/3 nut, outer surface puberulent, inner surface half to fully pubescent, scale tips tightly appressed, acute; nut broadly ovoid to globose, 9.5-14 × 8-13 mm, glabrate, scar diam. 5-8 mm.
Cotyledons	distinct.
Terminal		buds reddish to purplish brown, ovoid, 2-5.5 mm, glabrous or with tuft of tawny hairs at apex.

	Quercus cornelius-mulleri	Quercus myrtifolia
Phenology	Flowering early spring.	Flowering spring.
Habitat	Open chaparral, pinyon and juniper woodlands, desert margins, often on loose granitic soils	Dunes, hammocks, sandhills, dry sandy ridges, and oak scrub
Elevation	1000-1800 m (3300-5900 ft)	0-100 m (0-300 ft)
Distribution	CA; Mexico (Baja California) [WildflowerSearch map] [BONAP county map]	AL; FL; GA; MS; SC [WildflowerSearch map] [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.)	This species flowers one to two weeks earlier than Q. inopina (A. F. Johnson and W. G. Abrahamson 1982). Quercus myrtifolia reportedly hybridizes with Q. incana (= Q. ×oviedoensis Sargent), but E. J. Palmer (1948) questioned the identification of the type specimen; the brief description by Sargent suggests that the specimen may be from an individual of Q. inopina. D. M. Hunt (1989) cited evidence of hybridization with Q. arkansana, Q. hemisphaerica, Q. inopina, Q. laurifolia, Q. marilandica, Q. nigra, and Q. pumila (Hunt suggested that the last may give rise to occasional reports of annual fruiting in Q. myrtifolia). (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. 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. 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
Name authority	Nixon & K. P. Steele: Madroño 28: 210. (1981)	Willdenow: Sp. Pl. 4(1): 424. (1805)
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 myrtifolia

desert scrub oak, muller oak, muller's oak

myrtle oak

Habit

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

Trees or shrubs, evergreen, to 12 m. Bark gray and smooth distally, dark and shallowly furrowed near base.

Twigs

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

dark red-brown, 1-2.5(-3) mm diam., persistently pubescent, rarely almost glabrous.

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 elliptic to narrowly or broadly obovate, occasionally spatulate, 15-50(-70) × 10-25(-35) mm, base cuneate to rounded, margins entire, somewhat revolute, with 1-4 awns, apex obtuse or rounded;

surfaces abaxially glabrous except for axillary tufts of tomentum, occasionally yellow-scurfy, adaxial surface planar, glabrous.

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 saucer-shaped to shallowly goblet-shaped, 4-7 mm high × 8.5-14.5 mm wide, covering 1/4-1/3 nut, outer surface puberulent, inner surface half to fully pubescent, scale tips tightly appressed, acute;

nut broadly ovoid to globose, 9.5-14 × 8-13 mm, glabrate, scar diam. 5-8 mm.

Cotyledons

distinct.

Terminal

buds reddish to purplish brown, ovoid, 2-5.5 mm, glabrous or with tuft of tawny hairs at apex.

Quercus cornelius-mulleri

Quercus myrtifolia

Phenology

Flowering early spring.

Flowering spring.

Habitat

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

Dunes, hammocks, sandhills, dry sandy ridges, and oak scrub

Elevation

1000-1800 m (3300-5900 ft)

0-100 m (0-300 ft)

Distribution

CA; Mexico (Baja California)

[WildflowerSearch map]

[BONAP county map]

AL; FL; GA; MS; SC

[WildflowerSearch map]

[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.)

This species flowers one to two weeks earlier than Q. inopina (A. F. Johnson and W. G. Abrahamson 1982).

Quercus myrtifolia reportedly hybridizes with Q. incana (= Q. ×oviedoensis Sargent), but E. J. Palmer (1948) questioned the identification of the type specimen; the brief description by Sargent suggests that the specimen may be from an individual of Q. inopina. D. M. Hunt (1989) cited evidence of hybridization with Q. arkansana, Q. hemisphaerica, Q. inopina, Q. laurifolia, Q. marilandica, Q. nigra, and Q. pumila (Hunt suggested that the last may give rise to occasional reports of annual fruiting in Q. myrtifolia).

(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. 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. 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

Name authority

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

Willdenow: Sp. Pl. 4(1): 424. (1805)

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).

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Quercus cornelius-mulleri

Quercus myrtifolia

Quercus cornelius-mulleri

Quercus myrtifolia