Flora of Scotts Creek Watershed
Lithocarpus densiflorus - Tanoak
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Family Name: Fagaceae
Common Names: Tanoak, Tan Oak, Tanbark Oak
Origin: Native to California
Habitat: Forests, woodlands, chaparrals, below 6500 ft.
Life Form and Duration: Perennial Tree or shrub, single or multistemmed. Up to 30 m tall.
Comments on overall growth: Usually an erect single stemmed tree with rounded crowns and long clear trunks. On harsh sites or in understory is more likely to be multistemmed or a shrub with broad spreading crowns.
Bark and Stem Description: Twigs hairy. Bark grayish brown, 2.5-7.5 cm thick, and fissured.
Foliage Type: Evergreen
Foliage Description: Simple, alternate. Blades are leathery, ovate to oblong, 2.5-14 cm long, base rounded, tip obtuse, margins variable - serrate to entire, upper surfaces dark green and hairless to slightly hairy, lower surfaces light green and densely hairy/woolly becoming hairless.
Infloresence Description: Monoecious, upright catkins with many staminate flowers at tip and 1-few pistillate flowers at base. Staminate flowers yellowish white, pistillate flowers brownish green.
Flowering Season: June-October
Fruit Type: Acorn
Fruit Description: Nut enclosed by cup-like involucre, matures in 2 years. Acorn cap (cup-like involucre) shallow, cap scales slender, spreading/reflexed from cap, giving bristly/bushy appearance. Nut ovoid to spherical, yellowish-brown, 2-4 cm. Acorn occurs singly or in pairs.
Plant Use: "Acorns historically used by Native Americans as a food staple. They were ground, leached and then prepared as a soup, cooked mush, or baked similar to a bread. The name Tanoak comes from the use of tannins in the bark in the process of tanning leather."
Common Associates: Umbellularia californica, Arbutus menziesii