Quercus arizonica |
Quercus laceyi |
|
---|---|---|
Arizona oak, Arizona white oak |
lacey oak |
|
Habit | Trees, evergreen or subevergreen, small to moderate-sized trees, rarely to 18 m. Bark scaly. | Trees, deciduous, to 5-8(-10) m. Bark light colored, papery or scaly. |
Twigs | yellowish, 1.5-2.5 mm diam., persistently felty-tomentose, eventually dingy gray. |
gray, 1.5-2 mm diam., pubescent with erect stellate hairs, these soon shed, at maturity reddish and pruinose to tan and glabrous. |
Buds | dull russet-brown, ovoid, distally subacute or rounded, 3 mm, sparsely pubescent or glabrate. |
brown, ovoid to ovoid-lanceoloid, 1.5-3 × 1-2 mm, apex acute, glabrous. |
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 blue-green, glaucous, obovate or elliptic, (20-)40-90(-210) × (20-)30-60(-110) mm, thin, base cuneate and decurrent on petiole to rounded or rarely somewhat cordate, margins thin, flat, entire to shallowly lobed or (rarely in shade forms) deeply lobed, lobes if present oblong, squarish, often retuse, secondary veins 6-9 on each side, each terminating in tooth or arching near margins, apex broadly rounded, retuse; surfaces abaxially whitish, with erect stellate hairs, hairs shed as leaves expand, becoming glabrous, glaucous, adaxially glabrous, glaucous. |
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. |
annual, solitary or paired, subsessile or on short peduncle to 10(-20) mm in leaf axil; cup saucer-shaped or shallowly cup-shaped, 4-7 mm deep × 10-12(-18) mm wide, enclosing 1/3 nut or less, scales moderately tuberculate, finely tomentose; nut oblong or barrel-shaped, often flattened at both ends, (11-)13-15(-20) × 9-11(-14) mm. |
Cotyledons | connate. |
distinct. |
Quercus arizonica |
Quercus laceyi |
|
Phenology | Flowering spring. | Flowering in spring. |
Habitat | Oak and pinyon woodlands, margins of chaparral, arroyos | Limestone hills, woodlands and riparian forests, canyons and streamsides |
Elevation | 1300-2500(-3000) m (4300-8200(-9800) ft) | 350-2200 m (1100-7200 ft) |
Distribution |
AZ; NM; TX; Mexico (Chihuahua, Coahuila, Durango, and Sonora)
|
TX; Mexico (Coahuila and Nuevo León) |
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.) |
Material from Texas and northeastern Mexico, excluding the type, has been incorrectly referred to Quercus glaucoides M. Martens & Galeotti by some authors (K. C. Nixon and C. H. Muller 1992). On the Edwards Plateau of Texas, Quercus laceyi occurs mostly at 350-600 m elevation; in Coahuila and Nuevo León, it occurs at 1500-2200 m. This species is sometimes associated with remnant mesic forests, which include Acer grandidentatum Nuttall, Tilia species, Quercus muhlenbergii Engelmann, and various pine and other oak species. The leaves are shallowly lobed or entire, although occasional specimens on moist sites are deeply lobed and resemble the leaves of Q. alba in outline. (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. breviloba subsp. laceyi |
Name authority | Sargent: Gard. & Forest 8: 92. (1895) | Small: Bull. Torrey Bot. Club 28: 358. (1901) |
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