Quercus arizonica |
Quercus inopina |
|
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Arizona oak, Arizona white oak |
sandhill oak |
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Habit | Trees, evergreen or subevergreen, small to moderate-sized trees, rarely to 18 m. Bark scaly. | Shrubs, evergreen, to 5 m. Bark gray. |
Twigs | yellowish, 1.5-2.5 mm diam., persistently felty-tomentose, eventually dingy gray. |
light to dark purplish brown, (1.5-)2-3(-4) mm diam., glabrate to sparsely pubescent, especially at apex. |
Buds | dull russet-brown, ovoid, distally subacute or rounded, 3 mm, sparsely pubescent or glabrate. |
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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 ovate or elliptic to obovate, occasionally spatulate, (25-)45-85 × (15-)25-45 mm, base acute to rounded or cordate, margins entire, strongly revolute, with 1 apical awn, apex obtuse or rounded; surfaces abaxially yellow-scurfy, occasionally somewhat pubescent, rarely glabrous, adaxially distinctly convex, rugose, glabrous or with scattered hairs, especially along midrib and at base. |
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. |
biennial; cup cup-shaped to bowl-shaped, 6-8 mm high × 10-15 mm wide, covering 1/3-1/2 nut, outer surface puberulent, inner surface half to fully pubescent, scale tips tightly appressed, acute; nut ovoid to broadly ellipsoid, 10-14 × 9-13 mm, glabrate, scar diam. 4.5-8 mm. |
Cotyledons | connate. |
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Terminal | buds dark purplish brown, ovoid to subconic, 2-6 mm, noticeably 5-angled in cross section, glabrous to tawny strigose on apical 1/3. |
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Quercus arizonica |
Quercus inopina |
|
Phenology | Flowering spring. | Flowering spring. |
Habitat | Oak and pinyon woodlands, margins of chaparral, arroyos | On deep white "sugar" sands of low sandhill ridges, scrub communities, and flat upland terraces |
Elevation | 1300-2500(-3000) m (4300-8200(-9800) ft) | 0-50 m (0-200 ft) |
Distribution |
AZ; NM; TX; Mexico (Chihuahua, Coahuila, Durango, and Sonora)
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FL
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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.) |
Quercus inopina occurs from Orange County, Florida, southwest to Manatee County and south to Martin County. It flowers one to two weeks later than Q. myrtifolia (A. F. Johnson and W. G. Abrahamson 1982). The leaves of this species often have numerous small black dots on the adaxial surface. These are ascocarps (the sexual fruiting bodies of ascomycete fungi) of the genus Asterina (D. M. Hunt, pers. comm). Although no hybrids have been formally described, evidence of hybridization of Quercus inopina with Q. hemisphaerica, Q. laevis, and Q. myrtifolia has been reported (D. M. Hunt 1989). (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 | ||
Synonyms | Q. sacame | |
Name authority | Sargent: Gard. & Forest 8: 92. (1895) | Ashe: Rhodora 31: 79. (1929) |
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