Quercus arizonica |
Quercus pungens |
|
---|---|---|
Arizona oak, Arizona white oak |
pungent oak, sandpaper oak |
|
Habit | Trees, evergreen or subevergreen, small to moderate-sized trees, rarely to 18 m. Bark scaly. | Shrubs or moderate-sized trees, evergreen or subevergreen. |
Bark | light brown, papery. |
|
Twigs | yellowish, 1.5-2.5 mm diam., persistently felty-tomentose, eventually dingy gray. |
gray, 1-2 mm diam., short velvety-tomentose, glabrate with age. |
Buds | dull russet-brown, ovoid, distally subacute or rounded, 3 mm, sparsely pubescent or glabrate. |
dark red-brown, ca. 2 mm, sparsely pubescent. |
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 oblong, 10-40(-90) × 10-20(-40) mm, rather thick, leathery, stiff, base rounded or minutely cordate, very rarely cuneate, margins regularly undulate-crisped, not revolute, coarsely toothed or incised with acute teeth or spinose lobes, secondary veins 5-8(-14) on each side, usually branched before passing into teeth, apex acute or obtuse, rarely rounded, spine-tipped; surfaces abaxially canescent, usually densely stellate-pubescent, and mixed with stiff, harsh, stellate hairs, often sandpapery to touch, rarely glabrate, adaxially yellowish green, glossy, usually rough and sandpapery because of minute, persistent hair bases, rarely glabrate. |
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. |
subsessile or on peduncle to 3 mm; cup shallowly to deeply cup-shaped or turbinate, to 8 mm deep × 13 mm wide, covering ca. 1/4 nut, margin thin, scales reddish brown, moderately tuberculate or keeled, densely gray-tomentose; nut light brown, broadly ovoid to subcylindric, to 10 × 10 mm, apex rounded to subacute, glabrous. |
Cotyledons | connate. |
distinct. |
Quercus arizonica |
Quercus pungens |
|
Phenology | Flowering spring. | Flowering spring. |
Habitat | Oak and pinyon woodlands, margins of chaparral, arroyos | On dry limestone or igneous slopes, usually in oak, pinyon, and juniper woodlands, chaparral, and sometimes descending into desert vegetation |
Elevation | 1300-2500(-3000) m (4300-8200(-9800) ft) | 800-2000 m (2600-6600 ft) |
Distribution |
AZ; NM; TX; Mexico (Chihuahua, Coahuila, Durango, and Sonora)
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AZ; NM; TX; Mexico (Chihuahua and Coahuila)
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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.) |
Numerous populations appear to be hybrid swarms between Quercus pungens and Q. vaseyana, which is sometimes treated as a variety of Q. pungens. No other evidence for a close relationship exists for these two species, and such a treatment risks erecting a polyphyletic assemblage. To the west and south within the range of Q. pungens no indication of introgression exists, and the two species are strikingly different and easily separable. I interpret the contact as secondary. (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. undulata var. pungens |
Name authority | Sargent: Gard. & Forest 8: 92. (1895) | Liebmann: Overs. Kongel. Danske Vidensk. Selsk. Forh. Medlemmers Arbeider 1854: 171. 185: not Q. pungens Gandoger 1890 |
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