FNA: Quercus fusiformis vs. Quercus cornelius-mulleri

	Quercus fusiformis	Quercus cornelius-mulleri
	escarpment live oak, live oak, plateau oak, Texas live oak	desert scrub oak, muller oak, muller's oak
Habit	Trees, sometimes shrubs, subevergreen, trees to 25 m, shrubs often forming large clonal stands.	Shrubs, evergreen or subevergreen, densely branched, 1-2(-3) m. Bark gray, scaly.
Bark	dark brown or black, scaly.
Twigs	light gray, 1.5-3 mm diam., tomentulose, tomentulum often persistent in age.	gray, yellowish, or brownish, 1-1.5 mm diam., densely tomentulose, rarely glabrate.
Buds	reddish or dark brown, subglobose or ovate, 1.5-3 mm; scale margins glabrous or puberulent.	dull brown, ovoid, 2.5-3 mm, glabrous except for margins of scales.
Leaves	blade oblong-elliptic to narrowly ovate or lanceolate, sometimes obovate, ± planar, (10-)35-90(-150) × (15-)20-40(-85) mm, base rounded to truncate or cordate, rarely cuneate, margins minutely revolute or flat, entire or irregularly 1-3 toothed on each side, teeth mucronate (rarely spinose in suckers or juveniles), secondary veins obscure, 8-10 on each side, apex obtuse-rounded or acute; surfaces abaxially whitish or glaucous, densely covered with minute, appressed, fused-stellate hairs, light green and glabrate in shade leaves, adaxially dark or light green, glossy, glabrous or with minute, scattered, stellate hairs.	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.
Acorns	1-3, on peduncle 3-30 mm; cup funnel-shaped, hemispheric, or deeply goblet-shaped, 8-15 mm deep × 6-12(-15) mm wide, base often constricted, scales whitish or grayish, thickened basally, keeled, acute-attenuate, tomentulose, tips reddish, glabrous or puberulent; nut dark brown, often with light brown longitudinal stripes, subfusiform and acute to narrowly barrel-shaped, rarely distally rounded, (17-)20-30(-33) × 8-15 mm, glabrous.	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.
Cotyledons	connate.	distinct.

	Quercus fusiformis	Quercus cornelius-mulleri
Phenology	Flowering spring.	Flowering early spring.
Habitat	Hills, grasslands, scrublands, open woodlands, oak-juniper woodland, and margins of thorn scrub, often on limestone or deep calcareous loams, sometimes on granular sand or gravel	Open chaparral, pinyon and juniper woodlands, desert margins, often on loose granitic soils
Elevation	0-1200 m (0-3900 ft)	1000-1800 m (3300-5900 ft)
Distribution	OK; TX; Mexico (Coahuila, Nuevo León, and Tamaulipas) [WildflowerSearch map] [BONAP county map]	CA; Mexico (Baja California) [WildflowerSearch map] [BONAP county map]
Discussion	The difficulty in distinguishing Texas populations of Quercus fusiformis from Q. virginiana is reflected in a variety of taxonomic treatments, including reducing Q. fusiformis to varietal rank under Q. virginiana. The latter disposition is problematic, however, because Q. fusiformis in northeastern Mexico is amply distinct from Q. virginiana and appears to be more closely related to Q. brandegei Goldmann, an endemic of Baja California, Mexico. Thus, here we assume that the intergradation of Q. virginiana and Q. fusiformis is a result of secondary contact, and is not primary clinal variation. Under this interpretation, Q. virginiana in typical form extends into Texas only as far west as the Brazos River drainage along the coast from there to the escarpment of the Edwards Plateau; most populations elsewhere are either intermediate between the two species or show greater affinity with Q. fusiformis. On the Edwards Plateau, the live oak populations are small trees forming rhizomatous copses (shinneries) and having mostly acute acorns. Populations of live oak on deep sands in south Texas differ from typical Quercus fusiformis in having broader, more rounded leaves, often with the secondary veins somewhat impressed abaxially, and relatively blunt, barrel-shaped acorns. These characteristics suggest introgresion from the Mexican-Central American species Q. oleoides Schlechtendal & Chamisso, which in its typical form reaches north only as far as southern Tamaulipas, Mexico. The name Q. oleoides var. quaterna C. H. Muller has been applied to what is apparently a shrub form of one of these Q. fusiformis × Q. oleoides hybrids. (Discussion copyrighted by Flora of North America; reprinted with permission.)	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.)
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. dumosa, Q. durata, Q. ellipsoidalis, Q. emoryi, Q. engelmannii, Q. falcata, 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. 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. virginiana var. fusiformis
Name authority	Small: Bull. Torrey Bot. Club 28: 357. (1901)	Nixon & K. P. Steele: Madroño 28: 210. (1981)
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 cornelius-mulleri

escarpment live oak, live oak, plateau oak, Texas live oak

desert scrub oak, muller oak, muller's oak

Habit

Trees, sometimes shrubs, subevergreen, trees to 25 m, shrubs often forming large clonal stands.

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

Bark

dark brown or black, scaly.

Twigs

light gray, 1.5-3 mm diam., tomentulose, tomentulum often persistent in age.

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

Buds

reddish or dark brown, subglobose or ovate, 1.5-3 mm;

scale margins glabrous or puberulent.

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

Leaves

blade oblong-elliptic to narrowly ovate or lanceolate, sometimes obovate, ± planar, (10-)35-90(-150) × (15-)20-40(-85) mm, base rounded to truncate or cordate, rarely cuneate, margins minutely revolute or flat, entire or irregularly 1-3 toothed on each side, teeth mucronate (rarely spinose in suckers or juveniles), secondary veins obscure, 8-10 on each side, apex obtuse-rounded or acute;

surfaces abaxially whitish or glaucous, densely covered with minute, appressed, fused-stellate hairs, light green and glabrate in shade leaves, adaxially dark or light green, glossy, glabrous or with minute, scattered, stellate hairs.

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.

Acorns

1-3, on peduncle 3-30 mm;

cup funnel-shaped, hemispheric, or deeply goblet-shaped, 8-15 mm deep × 6-12(-15) mm wide, base often constricted, scales whitish or grayish, thickened basally, keeled, acute-attenuate, tomentulose, tips reddish, glabrous or puberulent;

nut dark brown, often with light brown longitudinal stripes, subfusiform and acute to narrowly barrel-shaped, rarely distally rounded, (17-)20-30(-33) × 8-15 mm, glabrous.

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.

Cotyledons

connate.

distinct.

Quercus fusiformis

Quercus cornelius-mulleri

Phenology

Flowering spring.

Flowering early spring.

Habitat

Hills, grasslands, scrublands, open woodlands, oak-juniper woodland, and margins of thorn scrub, often on limestone or deep calcareous loams, sometimes on granular sand or gravel

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

Elevation

0-1200 m (0-3900 ft)

1000-1800 m (3300-5900 ft)

Distribution

OK; TX; Mexico (Coahuila, Nuevo León, and Tamaulipas)

[WildflowerSearch map]

[BONAP county map]

CA; Mexico (Baja California)

[WildflowerSearch map]

[BONAP county map]

Discussion

The difficulty in distinguishing Texas populations of Quercus fusiformis from Q. virginiana is reflected in a variety of taxonomic treatments, including reducing Q. fusiformis to varietal rank under Q. virginiana. The latter disposition is problematic, however, because Q. fusiformis in northeastern Mexico is amply distinct from Q. virginiana and appears to be more closely related to Q. brandegei Goldmann, an endemic of Baja California, Mexico. Thus, here we assume that the intergradation of Q. virginiana and Q. fusiformis is a result of secondary contact, and is not primary clinal variation. Under this interpretation, Q. virginiana in typical form extends into Texas only as far west as the Brazos River drainage along the coast from there to the escarpment of the Edwards Plateau; most populations elsewhere are either intermediate between the two species or show greater affinity with Q. fusiformis. On the Edwards Plateau, the live oak populations are small trees forming rhizomatous copses (shinneries) and having mostly acute acorns.

Populations of live oak on deep sands in south Texas differ from typical Quercus fusiformis in having broader, more rounded leaves, often with the secondary veins somewhat impressed abaxially, and relatively blunt, barrel-shaped acorns. These characteristics suggest introgresion from the Mexican-Central American species Q. oleoides Schlechtendal & Chamisso, which in its typical form reaches north only as far as southern Tamaulipas, Mexico. The name Q. oleoides var. quaterna C. H. Muller has been applied to what is apparently a shrub form of one of these Q. fusiformis × Q. oleoides hybrids.

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

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.)

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. dumosa, Q. durata, Q. ellipsoidalis, Q. emoryi, Q. engelmannii, Q. falcata, 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. 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. virginiana var. fusiformis

Name authority

Small: Bull. Torrey Bot. Club 28: 357. (1901)

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

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 fusiformis

Quercus cornelius-mulleri

Quercus fusiformis

Quercus cornelius-mulleri