Shrubs or trees, evergreen, usually moderate-sized, rarely large. Bark light or dark brown, scaly. Twigs brown, turning gray with age, 1-2 mm diam., tomentose to tomentulose, variously glabrate or persistently pubescent. Buds brown, ovoid, 2-4 mm, apex obtuse, sparsely pubescent or eventually glabrate. Leaves: petiole to 7 mm. Leaf blade broadly obovate or panduriform to orbiculate or elliptic, rarely narrowly obovate, usually cupped, strongly concave proximally, sometimes planar, to 100 × 70 mm, stiff, leathery, base deeply or shallowly cordate, margins usually somewhat revolute, cartilaginously thickened, undulately crisped or flat with inconspicuous or coarse mucronate teeth near apex, secondary veins 8-10(-12) on each side, branched, apex broadly rounded, rarely subacute; surfaces abaxially dull, glaucous, or densely brownish tomentose, becoming nearly glabrate or pubescence persistent, especially about midribs, secondary veins very prominently raised, reticulate, adaxially dark green, lustrous, sparsely stellate-pubescent especially about base of midrib, secondary veins impressed. Acorns 1-3 or more on slender axillary peduncle 30-60 mm; cup deeply cup-shaped to saucer-shaped, to 9 mm deep × 15 mm wide, enclosing to 1/2 nut, scales loosely appressed, characteristically somewhat spreading, brown, ovate, tuberculate-thickened or only slightly so, tomentose or obscurely tomentulose; nut light brown, ovoid to elliptic, to 20 × 15 mm, glabrous or minutely villous. Cotyledons distinct, often reddish or purple.
Phenology: Flowering early–late spring.
Habitat: Wooded slopes
Elevation: 2000-2500 m
Ariz., N.Mex., Tex., Mexico, Central America (Guatemala).
Quercus rugosa occurs on wooded slopes at high elevations in trans-Pecos Texas, southern New Mexico, and Arizona, and throughout most of the mesic montane parts of Mexico, south to Guatemala.