Native to (or naturalized in) Oregon:
- Broadleaf evergreen tree/shrub, 20-30(90) ft [6-9(27) m] high, varying from narrow and conical to broad and rounded; sometimes a shrub, less than 10 ft (3m) [L. d. var. echinoides, Shrub Tanoak]. Leaves oblong, 6-13 cm long, 2-6 cm wide, thick, leathery, wavy-toothed border, shiny light green, whitish beneath (tawny pubescence when first unfolded), margin coarsely toothed to entire, often revolute (rolled under). Flowers are unisexual, male (pollen) flowers are in catkins 5-10 cm long, white but turning rust colored, with an unpleasant odor; greenish-yellow female (seed) flowers are found at the base of catkins. Fruit (acorns) are egg-shaped, 2-3 cm long, shallow saucer-shaped cup, covered with dense bristles; mature in the second year.
- Sun or partial shade, very shade tolerant. Best in rich, moist soil. Stands some drought when established. One of the few evergreen, broad-leaved trees for the Willamette Valley.
- Hardy to USDA Zone 7 Native range from southwest Oregon (Cascade Mountains through the Klamath Mountains) to southern California.
- Note: Some authorities have moved Tanbark-oak into a new genus, Notholithocarpus, based on molecular and other lines of evidence. It is not related to the Asian tropical stone oaks, Lithocarpus, but rather is more closely related to the north temperate oaks, Quercus. Notholithocarpus: notho, false; lithocarpus.
- Lithocarpus: from Greek lithos, stone, and karpos, fruit, alluding to the hard fruit (acorn). densiflorus: densely flowered
- Its acorns are oak-like, but is flowers are like those of chestnuts or chinkapins. Native Americans removed the shells of the acorn, washed the seeds in hot water to remove the tannins, and then ground them into flour.
- Oregon State Univ., Peavy Arboretum.