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Arizona oak, Arizona white oak

Gambel oak

Habit Trees, evergreen or subevergreen, small to moderate-sized trees, rarely to 18 m. Bark scaly. Shrubs or trees, deciduous, shrubs sometimes clumped and spreading, trees small or moderately large.
Bark

gray or brown, scaly.

Twigs

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

brown or reddish brown with few, inconspicuous lenticels, 1.5-2.5 mm diam., glabrous or stellate-pubescent.

Buds

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

brown, ovoid, ca. 3 mm, apex acute or obtuse, sparsely pubescent, becoming glabrate.

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 elliptic to obovate or oblong, deeply to shallowly 4-6-lobed, (40-)80-120(-160) × (25-)40-60(-100) mm, membranous, base truncate to cuneate, margins entire or coarsely toothed, lobes oblong, rounded or subacute, sinuses acute or narrowly rounded at base, reaching more than 1/2 distance to midrib, secondary veins 4-6 on each side, each passing into lobe, branched, apex broadly rounded;

surfaces abaxially dull green, sometimes glaucous, densely velvety with erect 4-6-rayed hairs, sometimes glabrate or persistently villous only near midribs, secondary veins prominent, adaxially lustrous dark green, appearing glabrate, microscopically pubescent, secondary veins slightly raised.

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.

solitary or paired, subsessile or on peduncle to 10(-30) mm;

cup deeply cup-shaped, 5-8(-17) mm deep × 7-15(-25) mm wide, enclosing 1/4-1/2 nut, base round, margin thin, scales closely appressed, ovate, markedly tuberculate, proximally gray-tomentulose;

nut light brown, ovoid to ellipsoid, (8-)12-15(-33) × 7-12(-18) mm.

Cotyledons

connate.

distinct.

Quercus arizonica

Quercus gambelii

Phenology Flowering spring. Flowering mid-late spring.
Habitat Oak and pinyon woodlands, margins of chaparral, arroyos Montane conifer, oak-maple, and higher margins of pinyon-juniper woodlands
Elevation 1300-2500(-3000) m (4300-8200(-9800) ft) 1000-3030 m (3300-9900 ft)
Distribution
from FNA
AZ; NM; TX; Mexico (Chihuahua, Coahuila, Durango, and Sonora)
[WildflowerSearch map]
[BONAP county map]
from FNA
AZ; CO; NM; NV; OK; TX; UT; WY; Mexico (Chihuahua, Coahuila, and Sonora)
[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.)

Numerous hybrids of Quercus gambelii with various scrub oaks have been reported, including Q. grisea and Q. turbinella. Such hybrids in general have shallowly lobed or dentate, semipersistent leaves and intermediate characteristics of pubescence and fruit between parental types. Such hybrids are usually referred to as the Quercus ×undulata complex because of widespread application of the latter name to various populations.

One population from San Juan County, Utah, with larger fruit but otherwise not differing from typical Quercus gambelii, has been recognized as Q. gambelii var. bonina Welsh. Unless other characters are found to support this segregation, the plants are best not treated as a formal taxon, particularly considering the extensive variation and hybridization associated with Q. gambelii throughout its range.

Numerous putative hybrid swarms occur throughout the range of Quercus gambelii that involve a number of suspected parental species. Most of these populations have, at one time or another, been referred to Quercus undulata Torrey. The putative hybrids have serrate or shallowly lobed leaves and considerable variation in habit, leaf pubescence, and acorn morphology. J. M. Tucker (1961, 1969, 1971) and J. M. Tucker et al. (1961) have identified the major components of the Q. undulata complex as Q. turbinella (western Utah and northwestern Arizona, and central Colorado), Q. grisea (New Mexico and southern Colorado), Q. havardii (southeastern Utah and northwestern Arizona), Q. mohriana (northeastern and southern New Mexico), Q. arizonica (central Arizona), and Q. muhlenbergii (eastern and central New Mexico). Quercus macrocarpa has been implicated as a parent of variable populations in New Mexico (J. M. Tucker and J. R. Maze 1966). Because of the complex variability in these populations, no effort has been made to treat them separately here; indeed, it would be impossible to produce usable keys if these were included as formal taxa.

Hybrids derived from Quercus gambelii and an evergreen species are often semideciduous, retaining a variable portion of green or brownish leaves over the winter.

Quercus gambelii was used medicinally by the Navaho-Ramah to alleviate postpartum pain, as a cathartic, as a ceremonial emetic, and as a life medicine (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. 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. sacame Q. douglasii var. gambelii, Q. gambelii var. gunnisonii, Q. lesueuri, Q. marshii, Q. novomexicana, Q. undulata var. gambelii, Q. utahensis
Name authority Sargent: Gard. & Forest 8: 92. (1895) Nuttall: J. Acad. Nat. Sci. Philadelphia 1(2): 179. (1848)
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