Quercus turbinella |
Quercus sinuata |
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grey oak, shrub live oak, Sonoran scrub oak, turbinella oak |
bastard oak, bastard white oak, Durand oak, Durand white oak |
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Habit | Shrubs or small trees, evergreen or subevergreen, to 4 m. Bark light gray or brown, scaly. | Trees or shrubs, deciduous, to 15(-20) m, with solitary or multiple trunks. | ||||
Bark | gray to light brown, flaky to papery and exfoliating. |
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Twigs | brown to gray, 1-3 mm diam., usually tomentulose, sometimes glabrous, becoming glabrate. |
light gray or gray, 1-2(-3) mm diam., glabrous, rarely minutely puberulent. |
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Buds | brown, round to ovoid, 1-2 mm, minutely pubescent. |
brown or reddish brown, broadly ovoid, 2-3 mm, essentially glabrous. |
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Leaves | blade elliptic or ovate, (1.5-)20-30 × (5-)10-15(-20) mm, thick, leathery, base cordate or rounded, margins planar or slightly crisped-undulate, coarsely 3-5-toothed or very shallowly lobed on each side, teeth spinose with spines 1-1.5 mm, secondary veins 4-8 on each side, apex acute or obtuse; surfaces abaxially yellow or reddish, usually glaucous, minutely stellate-puberulent, adaxially grayish, glaucous, or yellowish glandular, glabrous or sparsely and minutely stellate-pubescent. |
blade oblong to oblanceolate, or narrowly rhomboid, or cuneiform, or rounded-3-dentate, (25-)30-120(-140) × (15-)25-60 mm, base acute, cuneate, attenuate-rounded, or obtuse, margins entire to irregularly toothed or moderately, sinuately lobed, flat, secondary veins ca. 7-11 on each side, apex broadly rounded, rarely attenuately narrowed or obscurely 3-lobed; surfaces abaxially silvery or dull green, with scattered to crowded, minute, appressed-stellate, 8-10-rayed hairs, or glabrate or glabrous, especially in shade forms, adaxially green or dull green, glabrous. |
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Acorns | solitary or several, on axillary peduncle 10-40 mm; cup hemispheric or shallowly cup-shaped, 4-6 mm deep × 8-12 mm wide, covering 1/4-1/2 nut, scales tightly appressed, ovate, moderately tuberculate, grayish or yellowish puberulent; nut light brown, ovoid, to 20 × 11 mm, minutely puberulent or glabrate. |
solitary or paired, subsessile or on axillary peduncle to 1-7 mm; cup saucer-shaped to shallowly cup-shaped, rarely deeper, 2-8 mm deep × 8-15(-20) mm wide, enclosing 1/8-1/4 nut, rarely more, base flat, rounded, or constricted, margin thin, scales closely appressed, grayish with reddish margins, ovate, flat, obtuse, not tuberculate; nut light brown, depressed-ovoid to oblong, 7-15 × 7-12(-17) mm, glabrous. |
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Cotyledons | distinct. |
distinct. |
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Quercus turbinella |
Quercus sinuata |
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Phenology | Flowering spring. | |||||
Habitat | Dry desert slopes, often in juniper and pinyon woodlands | |||||
Elevation | 800-2000 m (2600-6600 ft) | |||||
Distribution |
AZ; CA; CO; NM; NV; TX; UT; Mexico (Baja California, Sonora, and probably n Chihuahua)
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AL; AR; FL; GA; LA; MS; NC; OK; SC; TX
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Discussion | Formerly, California populations of what here is referred to as Quercus john-tuckeri have been included in the concept of Q. turbinella. Quercus john-tuckeri has subsessile fruit and noncordate leaf bases as opposed to the consistently pedunculate fruit and strongly cordate leaf bases of Q. turbinella. The two species seem to be no more closely related to each other than each might be to other southwestern oaks, and Q. john-tuckeri shares at least as many characteristics with Q. berberidifolia as with Q. turbinella. Thus, treatment of these two taxa as varieties of the same species is inappropriate. Quercus turbinella forms putative hybrid swarms with Q. gambelii (see treatment), as well as with Q. grisea. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Varieties 2 (2 in the flora). The question of the correct name for this species has persisted, with some authors rejecting the usage here in favor of Quercus durandii. Although no type material is extant, the original description of Q. sinuata is consistent with the concept presented here, as by W. W. Ashe (1916) and W. Trelease (1924), and inconsistent with any other oak from the broad area covered by Thomas Walter's Flora Caroliniana (1788). The two varieties differ in habit, habitat, leaf size and lobing, and geographic range, and considerable variability exists within both varities as to the degree and density of silvery stellate-pubescence on the abaxial surface of the leaf. Sun leaves of both tend to have a higher proportion of silvery pubescence, and shade leaves and some individual trees tend to have more glabrate leaves, although evidence of flat-stellate trichomes is usually apparent. Plants with young, expanding leaves sometimes are mistaken for Quercus nigra, a member of the red oak group. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Key |
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Source | FNA vol. 3. | FNA vol. 3. | ||||
Parent taxa | Fagaceae > Quercus > sect. Quercus | Fagaceae > Quercus > sect. Quercus | ||||
Sibling taxa | ||||||
Subordinate taxa | ||||||
Synonyms | Q. dumosa var. turbinella, Q. subturbinella | Q. durandii | ||||
Name authority | Greene: Ill. W. Amer. Oaks 1: 37. (1889) | Walter: Fl. Carol., 235. (1788) | ||||
Web links |