Quercus arizonica |
Quercus michauxii |
|
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Arizona oak, Arizona white oak |
basket oak, cow oak, swamp chestnut oak |
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Habit | Trees, evergreen or subevergreen, small to moderate-sized trees, rarely to 18 m. Bark scaly. | Trees, deciduous, to 20 m. Bark light brown or gray, scaly. |
Twigs | yellowish, 1.5-2.5 mm diam., persistently felty-tomentose, eventually dingy gray. |
brown or reddish brown, 2-3 mm diam., with sparse spreading hairs or glabrate. |
Buds | dull russet-brown, ovoid, distally subacute or rounded, 3 mm, sparsely pubescent or glabrate. |
reddish brown, ovoid, apex rounded or acute, glabrous or minutely puberulent. |
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 broadly obovate or broadly elliptic, (60-)100-280 × 50-180 mm, base rounded-acuminate or broadly cuneate, margins regularly toothed, teeth rounded, dentate, or acuminate, secondary veins 15-20 on each side, parallel, straight or somewhat curved, apex broadly rounded or acuminate; surfaces abaxially light green or yellowish, felty to touch because of conspicuous or minute, erect, 1-4-rayed hairs, adaxially glabrous or with minute simple or fascicled hairs. |
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. |
1-3, subsessile or more often on axillary peduncle to 20-30 mm; cup hemispheric, broadly hemispheric or even short-cylindric, 15-25 mm deep × 25-40 mm wide, enclosing 1/2 nut or more, scales very loosely appressed, distinct to base, gray or light brown, moderately to heavily tuberculate, tips silky-tomentose; nut light brown, ovoid or cylindric, 25-35 × 20-25 mm, glabrous. |
Cotyledons | connate. |
distinct. |
Quercus arizonica |
Quercus michauxii |
|
Phenology | Flowering spring. | Flowering early–late spring. |
Habitat | Oak and pinyon woodlands, margins of chaparral, arroyos | Bottomlands, rich sandy woods and swamps, on variety of soils |
Elevation | 1300-2500(-3000) m (4300-8200(-9800) ft) | 0-600 m (0-2000 ft) |
Distribution |
AZ; NM; TX; Mexico (Chihuahua, Coahuila, Durango, and Sonora)
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AL; AR; DE; FL; GA; IL; IN; KY; LA; MD; MO; MS; NC; NJ; PA; SC; TN; TX; VA
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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 michauxii is easily distinguished from other chestnut-leaved oaks by the felty hairs of the abaxial leaf surface and rather large acorn cups with attenuate-acute, loose scales. This species is no longer extant in Oklahoma. Historical reports from Connecticut, Massachusetts, and New York have not been confirmed; possibly populations are no longer extant. (See Quercus montana for a discussion of nomenclature and the uncertain application of the name Q. prinus). (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 | ||
Synonyms | Q. sacame | Q. houstoniana |
Name authority | Sargent: Gard. & Forest 8: 92. (1895) | Nuttall: Gen. N. Amer. Pl. 2: 215. (1818) |
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