Jepson eFlora Taxon Page

Common Name: OAK FAMILY
Habit: shrub, tree, evergreen or not; monoecious. Leaf: simple, alternate, petioled; margin entire to lobed; stipules small, generally deciduous. Staminate Inflorescence: catkin or stiff spike, many-flowered. Pistillate Inflorescence: 1--few-flowered, generally above staminate inflorescence; involucre bracts many, generally overlapping, flat or cylindric. Staminate Flower: calyx generally 4--6-lobed, minute; petals 0; stamens 4--12+. Pistillate Flower: calyx generally 6-lobed, minute; petals 0; ovary inferior, style branches generally 3. Fruit: 1 nut subtended, partly enclosed by scaly, cup-like involucre or 1--3 nuts subtended, enclosed by spiny, bur-like involucre; mature years 1--2. Seed: generally 1.

Genera In Family: 7 genera, +- 900 species: generally northern hemisphere. Note: Wood of Quercus critical for pre-20th century ship-building, charcoal for metallurgy; some now supply wood (Fagus, Quercus), cork (Quercus suber), food (Castanea, chestnut). Lithocarpus densiflorus moved to Notholithocarpus.

eFlora Treatment Author: John M. Tucker, except as noted
Scientific Editor: Thomas J. Rosatti, Bruce G. Baldwin.

Common Name: OAK
Habit: Evergreen or not. Leaf: stipules small, generally early-deciduous. Staminate Inflorescence: catkins, 1--several, pendent, slender, proximal on twig. Pistillate Inflorescence: in distal leaf axils, short-stalked; flower generally 1. Staminate Flower: stamens 4--10. Pistillate Flower: calyx minute, generally 6-lobed; ovary enclosed by involucre. Fruit: nut 1, partly enclosed by cup-like involucre (cup) with appressed scales (nut and cup = acorn), remnants of perianth and style persistent as small point at tip; scales tubercled to not; mature in years 1 (on younger stems) or 2 (on older stems). Chromosomes: 2n=24.

Etymology: (Latin: ancient name for oak) Note: Many named hybrids; those (3) treated here form widespread populations; most others occur as single individuals, and some but not all of these are mentioned here, under the first parent treated (alphabetically). Reproduction of many species declining due to habitat degradation or loss as well as disease. Quercus robur added, as waif.

eFlora Treatment Author: Thomas J. Rosatti & John M. Tucker

Leaf: adaxially strongly convex; abaxially short-hairy when young; margin rolled under.