Quercus arizonica |
Quercus carmenensis |
|
---|---|---|
Arizona oak, Arizona white oak |
Mexican oak |
|
Habit | Trees, evergreen or subevergreen, small to moderate-sized trees, rarely to 18 m. Bark scaly. | Shrubs or trees, deciduous, shrubs 0.5-2 m, rhizomatous, trees (on better sites) to 12 m, trunk 0.75 m diam. |
Bark | light gray, checkered or furrowed. |
|
Twigs | yellowish, 1.5-2.5 mm diam., persistently felty-tomentose, eventually dingy gray. |
often strikingly red, 1-1.5 mm diam., sparingly (rarely densely) stellate-pubescent, somewhat glabrescent and gray 2d year. |
Buds | dull russet-brown, ovoid, distally subacute or rounded, 3 mm, sparsely pubescent or glabrate. |
light brown, nearly round, 1-1.5 mm, indumentum similar to twigs. |
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 obovate or narrowly obovate, (20-)30-50 × 10-30 mm, thin to moderately leathery, base cuneate to rounded, margins shallowly and irregularly lobed or coarsely toothed in distal 1/2, rarely subentire, teeth mucronate, secondary veins 9-12 on each side, branching or passing directly to teeth, apex acute, sometimes broadly rounded; surfaces abaxially light green or yellow-green, prominently pubescent with minute, erect velvety hairs, adaxially surfaces dark green, sparsely and minutely stellate-pubescent. |
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 short-pedunculate (immature); cup (mature) unknown; scales (immature) light brown, tip acute, canescent. |
Cotyledons | connate. |
unknown. |
Nut | unknown. |
|
Quercus arizonica |
Quercus carmenensis |
|
Phenology | Flowering spring. | |
Habitat | Oak and pinyon woodlands, margins of chaparral, arroyos | Shrublands and woodlands on limestone |
Elevation | 1300-2500(-3000) m (4300-8200(-9800) ft) | 2200-2500 m (7200-8200 ft) |
Distribution |
AZ; NM; TX; Mexico (Chihuahua, Coahuila, Durango, and Sonora)
|
TX; Mexico (Coahuila) |
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.) |
Of conservation concern. Shrublands and woodlands on limestone; of conservation concern; 2200-2500 m; Tex.; Mexico (Coahuila). Quercus carmenensis is known in the United States from only one collection from the Chisos Mountains, Texas; otherwise, it is known in the Sierra del Carmen region, Coahuila, Mexico. (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 | |
Name authority | Sargent: Gard. & Forest 8: 92. (1895) | C. H. Muller: Amer. Midl. Naturalist 18: 847. (1937) |
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