Quercus arizonica |
Quercus coccinea |
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Arizona oak, Arizona white oak |
scarlet oak |
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Habit | Trees, evergreen or subevergreen, small to moderate-sized trees, rarely to 18 m. Bark scaly. | Trees, deciduous, to 30 m; lower trunk without stubs of dead branches. |
Bark | dark gray to dark brown, irregularly fissured with scaly ridges, inner bark orangish pink. |
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Twigs | yellowish, 1.5-2.5 mm diam., persistently felty-tomentose, eventually dingy gray. |
reddish brown, (1-)2-3.5 mm diam., glabrous. |
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 elliptic to ovate or obovate, 70-160 × 80-130 mm, base obtuse to truncate, margins with 5-9 deep lobes and 18-50 awns, lobes distally expanded, sinuses usually extending more than 1/2 distance to midrib, apex acute; surfaces abaxially glabrous except for minute axillary tufts of tomentum, adaxially glossy light green, glabrous, secondary veins raised on both surfaces. |
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 turbinate to hemispheric, 7-13 mm high × 16.5-31.5 mm wide, covering 1/3-1/2 nut, outer surface light to dark reddish brown, glossy, glabrous to puberulent, inner surface light brown, glabrous, occasionally with ring of pubescence around scar, scales often tuberculate, base broad, glossy, margins strongly concave with tips tightly appressed, acute to attenuate; nut oblong to subglobose, 12-22 × 10-21 mm, glabrous, with 1 or more rings of fine pits at apex, scar diam. 6.5-13.5 mm. |
Cotyledons | connate. |
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Terminal | buds dark reddish brown, conic to ovoid, 4-7 mm, noticeably 5-angled in cross section, usually silvery- or tawny-pubescent distal to middle. |
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2n | = 24. |
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Quercus arizonica |
Quercus coccinea |
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Phenology | Flowering spring. | Flowering spring. |
Habitat | Oak and pinyon woodlands, margins of chaparral, arroyos | Poor soils, well-drained uplands, dry slopes, and ridges, occasionally on poorly drained sites |
Elevation | 1300-2500(-3000) m (4300-8200(-9800) ft) | 0-1500 m (0-4900 ft) |
Distribution |
AZ; NM; TX; Mexico (Chihuahua, Coahuila, Durango, and Sonora)
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AL; AR; CT; DC; DE; GA; IL; IN; KY; MA; MD; ME; MI; MO; NC; NH; NJ; NY; OH; PA; RI; SC; TN; VA; VT; WI; WV
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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.) |
Trees having acorns with broad, distinctly warty cups are sometimes classified as Quercus coccinea var. tuberculata Sargent. Quercus coccinea reportedly hybridizes with Q. imbricaria, Q. ilicifolia (= Q. ×robbinsii Trelease), Q. laevis, and Q. palustris (E. J. Palmer 1948) and with Q. phellos, Q. rubra, and Q. velutina (= Q. ×fontana Laughlin). (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 | Q. coccinea var. tuberculata |
Name authority | Sargent: Gard. & Forest 8: 92. (1895) | Münchhausen: Hausvater 5(1): 254. (1770) |
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