Flora of North America species comparison

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Quercus arizonica

Quercus rubra

Arizona oak, Arizona white oak

chêne rouge, northern red oak, red oak
Habit Trees, evergreen or subevergreen, small to moderate-sized trees, rarely to 18 m. Bark scaly. Trees, deciduous, to 30 m. Bark gray or dark gray, ridges wide, shiny, separated by shallow fissures, inner bark pinkish.
Twigs

yellowish, 1.5-2.5 mm diam., persistently felty-tomentose, eventually dingy gray.

reddish brown, 2-3.5(-4.5) mm diam., glabrous.
Buds

dull russet-brown, ovoid, distally subacute or rounded, 3 mm, sparsely pubescent or glabrate.

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 ovate to elliptic or obovate, 120-200 × 60-120 mm, base broadly cuneate to almost truncate, margins with 7-11 lobes and 12-50 awns, lobes oblong, occasionally distally expanded, separated by shallow sinuses, sinuses usually extending less than 1/2 distance to midrib, apex acute;

surfaces abaxially pale green, often glaucous, glabrous except for minute axillary tufts of tomentum, adaxially dull 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 saucer- to cup-shaped, 5-12 mm high × 18-30 mm wide, covering 1/4-1/3 nut, outer surface puberulent, inner surface light brown to red-brown, glabrous or with ring of pubescence around scar, scales less than 4 mm, often with dark margins, tips tightly appressed, obtuse;

nut ovoid to oblong, 15-30 × 10-21 mm, glabrous, scar diam. 6.5-12.5 mm.
Cotyledons

connate.

Terminal

buds dark reddish brown, ovoid to ellipsoid, 4-7 mm, glabrous or with tuft of reddish hairs at apex.
2n

= 24.

Quercus arizonica

Quercus rubra
Phenology Flowering spring. Flowering spring.
Habitat Oak and pinyon woodlands, margins of chaparral, arroyos Commonly on mesic slopes and well-drained uplands, occasionally on dry slopes or poorly drained uplands
Elevation 1300-2500(-3000) m (4300-8200(-9800) ft) 0-1800 m (0-5900 ft)
Distribution
from FNA
AZ; NM; TX; Mexico (Chihuahua, Coahuila, Durango, and Sonora)
[WildflowerSearch map]
[BONAP county map]
from FNA
AL; AR; CT; DC; DE; GA; IA; IL; IN; KS; KY; MA; MD; ME; MI; MN; MO; MS; NC; NE; NH; NJ; NY; OH; OK; PA; RI; SC; TN; VA; VT; WI; WV; NB; NS; ON; PE; QC
[WildflowerSearch map]
[BONAP county map]
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 with large nuts only one-fourth covered by flat saucer-shaped cups often are treated as Quercus rubra var. rubra; those with smaller nuts one-third covered by cup- or bowl-shaped cups are treated as Q. rubra var. borealis (F. Michaux) Farwell. While E. J. Palmer (1942) suggested that these two varieties do not, K. M. McDougal and C. R. Parks (1986) found evidence of correspondence between morphologic types and flavonoid chemotypes. This is one of the most important ornamental and timber trees in the genus.

Native Americans used Quercus rubra for a number of medical purposes, including the treatment of sores, weakness, lung problems, sore throat, dysentery, indigestion, chapped skin, chills and fevers, lost voice, asthma, cough, milky urine, hear trouble, blood diseases, and Italian itch, and as an appetizer (D. E. Moerman 1986).

Quercus rubra reportedly hybridizes with Q. coccinea (= Q. ×benderi Baenitz) and Q. ellipsoidalis (P. C. Swain 1972; R. J. Jensen et al. 1993); with Q. ilicifolia (= Q. ×fernaldii Trelease), Q. imbricaria [Q. ×runcinata (A. de Candolle) Engelmann], and Q. marilandica (E. J. Palmer 1948; D. M. Hunt 1989); with Q. nigra (D. M. Hunt 1989); and with Q. palustris (= Q. ×columnaris Laughlin), Q. phellos (= Q. ×heterophylla F. Michaux), Q. shumardii (= Q. ×riparia Laughlin), and Q. velutina (= Q. ×hawkinsii Sudworth).

(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
Q. acerifolia, Q. agrifolia, Q. ajoensis, Q. alba, Q. arkansana, Q. austrina, Q. berberidifolia, Q. bicolor, Q. boyntonii, Q. buckleyi, Q. carmenensis, Q. chapmanii, Q. chihuahuensis, Q. chrysolepis, Q. coccinea, Q. cornelius-mulleri, Q. depressipes, Q. douglasii, Q. dumosa, Q. durata, Q. ellipsoidalis, Q. emoryi, Q. engelmannii, Q. falcata, Q. fusiformis, Q. gambelii, Q. garryana, Q. geminata, Q. georgiana, Q. graciliformis, Q. gravesii, Q. grisea, Q. havardii, Q. hemisphaerica, Q. hinckleyi, Q. hypoleucoides, Q. ilicifolia, Q. imbricaria, Q. incana, Q. inopina, Q. intricata, Q. john-tuckeri, Q. kelloggii, Q. laceyi, Q. laevis, Q. laurifolia, Q. lobata, Q. lyrata, Q. macrocarpa, Q. margarettae, Q. marilandica, Q. michauxii, Q. minima, Q. mohriana, Q. montana, Q. muehlenbergii, Q. myrtifolia, Q. nigra, Q. oblongifolia, Q. oglethorpensis, Q. pacifica, Q. pagoda, Q. palmeri, Q. palustris, Q. phellos, Q. polymorpha, Q. prinoides, Q. pumila, Q. pungens, Q. robur, Q. robusta, Q. rubra, Q. rugosa, Q. sadleriana, Q. shumardii, Q. similis, Q. sinuata, Q. stellata, Q. tardifolia, Q. texana, Q. tomentella, Q. toumeyi, Q. turbinella, Q. vacciniifolia, Q. vaseyana, Q. velutina, Q. viminea, Q. virginiana, Q. wislizenii
Q. acerifolia, Q. agrifolia, Q. ajoensis, Q. alba, Q. arizonica, Q. arkansana, Q. austrina, Q. berberidifolia, Q. bicolor, Q. boyntonii, Q. buckleyi, Q. carmenensis, Q. chapmanii, Q. chihuahuensis, Q. chrysolepis, Q. coccinea, Q. cornelius-mulleri, Q. depressipes, Q. douglasii, Q. dumosa, Q. durata, Q. ellipsoidalis, Q. emoryi, Q. engelmannii, Q. falcata, Q. fusiformis, Q. gambelii, Q. garryana, Q. geminata, Q. georgiana, Q. graciliformis, Q. gravesii, Q. grisea, Q. havardii, Q. hemisphaerica, Q. hinckleyi, Q. hypoleucoides, Q. ilicifolia, Q. imbricaria, Q. incana, Q. inopina, Q. intricata, Q. john-tuckeri, Q. kelloggii, Q. laceyi, Q. laevis, Q. laurifolia, Q. lobata, Q. lyrata, Q. macrocarpa, Q. margarettae, Q. marilandica, Q. michauxii, Q. minima, Q. mohriana, Q. montana, Q. muehlenbergii, Q. myrtifolia, Q. nigra, Q. oblongifolia, Q. oglethorpensis, Q. pacifica, Q. pagoda, Q. palmeri, Q. palustris, Q. phellos, Q. polymorpha, Q. prinoides, Q. pumila, Q. pungens, Q. robur, Q. robusta, Q. rugosa, Q. sadleriana, Q. shumardii, Q. similis, Q. sinuata, Q. stellata, Q. tardifolia, Q. texana, Q. tomentella, Q. toumeyi, Q. turbinella, Q. vacciniifolia, Q. vaseyana, Q. velutina, Q. viminea, Q. virginiana, Q. wislizenii
Synonyms Q. sacame Q. borealis, Q. maxima
Name authority Sargent: Gard. & Forest 8: 92. (1895) Linnaeus: Sp. Pl. 2: 996. (1753)
Web links 
Unless otherwise noted, all data comes from the online version of the Flora of North America, who have made most of their content available via a Creative Commons license (CC BY 4.0).



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