Flora of North America species comparison

The green links below add additional plants to the comparison table. Blue links lead to other Web sites.
enable glossary links

Quercus arizonica

Fagaceae

Arizona oak, Arizona white oak

beech family, oak family
Habit Trees, evergreen or subevergreen, small to moderate-sized trees, rarely to 18 m. Bark scaly. Trees or shrubs, evergreen or deciduous, shrubs sometimes rhizomatous.
Twigs

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

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 lobed or unlobed, pinnately veined, margins serrate, dentate, or entire;

surfaces usually pubescent, at least when young, sometimes with scales.
Inflorescences

unisexual or androgynous catkins; staminate and androgynous catkins spicate or capitate, rigid, flexible, or lax, consisting of few- to many-flowered clusters, bracts present or absent; pistillate catkins rigid or flexible, with 1-several spicately arranged, rarely solitary, terminal cupules bearing 1-3(-15 or more) pistillate flowers.
Staminate flowers

bracteate, bracts often caducous;

sepals (3-)4-6(-8);

stamens (3-)6-12(-18 or more);

petals absent;

anthers 2-locular, dehiscing by longitudinal slits, pollen sacs contiguous;

pistillode often present and indurate, or vestigial as central tuft of trichomes.
Pistillate flowers

calyx of 4-6 distinct or connate sepals;

petals absent;

pistil 1, 3(-6 or more)-carpellate;

ovary inferior, locules as many as carpels;

placentation axile;

ovules pendulous, 2 in each locule, all but 1 in each pistil usually aborting;

styles as many as carpels, distinct to base;

stigmas dry;

staminodes present or absent.
Fruits

nuts, sometimes winged, 1-seeded, subtended or enclosed individually or in groups of 2-3(-15) by scaly or spiny, multibracteate cupule;

seed coat membranous;

endosperm none;

embryo straight, as long as seed;

cotyledons fleshy, starchy or oily.
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.

Cotyledons

connate.

Winter

buds sessile, with few to many imbricate scales (2 valvate scales enclosing imbricate scales in Castanea);

terminal bud present or absent.

Quercus arizonica

Fagaceae
Phenology Flowering spring.
Habitat Oak and pinyon woodlands, margins of chaparral, arroyos
Elevation 1300-2500(-3000) m (4300-8200(-9800) ft)
Distribution
from FNA
AZ; NM; TX; Mexico (Chihuahua, Coahuila, Durango, and Sonora)
[WildflowerSearch map]
[BONAP county map]
Widespread; often dominant forest trees in temperate; subtropical; and tropical areas; mostly Northern Hemisphere
[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.)

Genera 9, species probably 600-800 (5 genera, 97 species, and numerous hybrids in the flora).

In the Western Hemisphere, Fagaceae are found from southern Canada to Colombia; they are absent or infrequent in most of the northern Great Plains and northern Rocky Mountain region.

Fagaceae are one of the most important families of Northern Hemisphere woody plants in terms of total biomass and economic use. They are widely used for lumber, firewood, and horticultural plantings; the nuts are often used for animal fodder and, in some species, for human food (particularly Castanea). As dominants in forests, woodlands, and chaparral, native stands of fagaceous trees and shrubs provide optimal wildlife habitat, often harboring an exceptionally diverse insect fauna. Most of the diversity of the family in the Western Hemisphere is concentrated in the genus Quercus, with the greatest number of species in Mexico (at least 125 species), and a secondary area of diversity in the southeastern United States.

Polyploidy has not been reported in any natural populations of species of Fagaceae. Natural interspecific hybridization is common in the family, particularly in Quercus, and also in Castanea and Lithocarpus.

The most important diagnostic feature of Fagaceae is the cupule, which occurs as the cup or cap of the acorn in Quercus and Lithocarpus and the spiny bur that surrounds the fruits of Castanea and Chrysolepis. The cupule is sometimes referred to as an involuc involucre, however, is made up of bracts, while the cupule has been shown to be a complex structure that is interpreted as an indurated, condensed, partial inflorescence formed by fusion of stem axes with several orders of branching, bearing bracts that are modified as scales and/or spines (see B. S. Fey and P. K. Endress 1983).

(Discussion copyrighted by Flora of North America; reprinted with permission.)
Key
1. Fruits acorns, acorn a solitary nut, circular in cross section, at least partially covered by scaly cup, cup unlobed, without visible sutures or valves; scales not noticeably spinose; nut not completely enclosed by cup at maturity (except in Quercus lyrata).
→ 2
1. Fruits of 1-several nuts, nut usually 3-angled or rounded-angular in cross section, enclosed in spiny or prickled cupule; cupule valves 2-4(-8+), distinct or marginally connate along sutures, these ±completely enveloping nut(s) until maturity.
→ 3
2. Cup scales strongly reflexed, hooked at tip; staminate and androgynous inflorescences erect or ascending, rigid or flexible, often appearing terminal and branched
Lithocarpus
2. Cup scales various, or if somewhat reflexed (rarely), then not noticeably hooked at tip; staminate inflorescences lax, axillary or clustered near base of new growth; androgynous inflorescences absent
Quercus
3. Spines/scales of cupule unbranched, stout, not obscuring surface of cupule; inflorescences unisexual (staminate below pistillate on same branch); pistillate flowers (and fruits) typically 2 per cupule; staminate inflorescences lax, loosely capitate; nut sharply angular, slightly winged
Fagus
3. Spines of cupule branched, interlocking and usually obscuring surface of cupule; inflorescences staminate and androgynous (staminate below androgynous on same twig); pistillate flowers (and fruits) 1-3 or many per cupule (rarely but not consistently 2); staminate inflorescences spicate, rigid or flexible; nut angular or rounded, not winged.
→ 4
4. Plants evergreen; leaves thick, leathery, margins entire (rarely spinose in sprouts), secondary veins obscure, not strongly parallel; adjacent nuts separated from each other by internal cupule valves; bud scales imbricate; spines of cupule without simple hairs, with large, yellowish, multicellular glands; styles
Chrysolepis
4. Plants winter-deciduous; leaves thin, somewhat leathery, secondary veins prominent, parallel, ending in prominent marginal teeth or awns; adjacent nuts not separated by cupule valves within cupule; buds with 2 unequal opposite outer scales that cover several imbricate inner scales; spines of cupule densely or sparsely with simple hairs; styles 6 or more
Castanea
Source FNA vol. 3. FNA vol. 3, p. 436. Author: Kevin C. Nixon.
Parent taxa Fagaceae > Quercus > sect. Quercus
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
Subordinate taxa
Castanea, Chrysolepis, Fagus, Lithocarpus, Quercus
Synonyms Q. sacame
Name authority Sargent: Gard. & Forest 8: 92. (1895) Dumortier
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).



Type/paste one or more Latin names into the boxes above; matching taxa will show up below the box as you type. You can use the up/down arrow keys to move through the list.

(If the plant you're looking for doesn't show up in the auto-complete list, that means it either isn't described in Flora of North America yet, or it's listed under a synonym. And please note that Flora of North America is still missing several plant families, including Fabaceae, Apiaceae, Boraginaceae, and Polemoniaceae.)

Choose a data source: Flora of North America, OregonFlora

The species comparison tool is brought to you by:
Northwest Wildflowers