FAGACEAE

OAK FAMILY

John M. Tucker

Shrub or tree, monoecious, deciduous or evergreen
Leaves simple, alternate, petioled; margin entire to lobed; stipules small, generally deciduous
Staminate inflorescence: catkin or stiff spike; flowers many
Pistillate inflorescence 1–few-flowered, generally above staminate inflorescence; involucre in fruit generally cup-like or lobed and bur-like, bracts many, generally overlapping, flat or cylindric
Staminate flower: sepals generally 5–6, minute; petals 0; stamens 4–12+
Pistillate flower: calyx generally 6-lobed, minute; petals 0; ovary inferior, style branches generally 3
Fruit: acorn (nut subtended by scaly, cup-like involucre) or 1–3 nuts subtended by spiny, bur-like involucre; nut maturing in 1–2 years
Seed generally 1
Genera in family: 7 genera, ± 900 species: generally n hemisphere. Wood of Quercus critical for pre-20th century ship-building, charcoal for metallurgy; some now supply wood (Fagus, Quercus ), cork (Q. suber ), food (Castanea , chestnut).

QUERCUS

OAK

Evergreen or deciduous
Leaf: stipules small, generally early deciduous
Staminate inflorescences: catkins, 1–several, slender, on proximal part of twig
Pistillate inflorescence axillary among upper leaves, short-stalked; flower generally 1
Staminate flower: calyx 4–6-lobed, minute; stamens 4–10
Pistillate flower: calyx minute, generally 6-lobed; ovary enclosed by involucre
Fruit: acorn, maturing in 1–2 years; nut enclosed by cup-like involucre with thin or tubercled scales
Chromosomes: 2n=24 for all reports
Species in genus: ± 600 species: n hemisphere, to n South America, India
Etymology: (Latin: ancient name for oak)
Many more hybrids have been named but are not included here. Reproduction of many species declining.

Native

Q. tomentella Engelm.

ISLAND OAK

Tree < 20 m, evergreen; trunk bark becoming furrowed, scaly, gray, sometimes reddish brown; young twigs tomentose
Leaf 5–8 cm; petiole 5–18 mm; blade oblong to oblong-ovate, tip acute to obtuse or abruptly pointed, margin toothed, teeth abruptly pointed, upper surface ± finely tomentose, becoming glabrous, dark green, lower surface densely tomentose, becoming sparsely woolly, dull, grayish green
Fruit maturing in 2 years; cup 20–30 mm wide, 6–8 mm deep, saucer- to bowl-shaped, scales thick, tubercled; nut 20–35 mm, widely ovoid, tip rounded, shell ± woolly inside
Ecology: UNCOMMON. Canyons, slopes, woodland
Elevation: < 600 m.
Bioregional distribution: Channel Islands
Distribution outside California: Baja California (Guadalupe Island)
Hybridizes with Q. chrysolepis.
Horticultural information: DRN: 5, 15, 16, 17 &IRR: 7, 14, 22, 23, 24 &SHD: 8, 9, 19, 20, 21.