Description :

• Deciduous or evergreen, monoecious, trees or shrubs; buds with imbricate scales
• Leaves alternate, simple, thin or leathery, entire, dentate, sinuate or pinnately lobed, rarely entire; stipules deciduous and inconspicuous
• Inflorescences unisexual, in axils of leaves or bud scales, usually clustered at base of new growth; male inflorescences lax, solitary or 1-3 together in pendulous spikes or catkins; female inflorescences solitary, in erect, stiff dichasia, 1-5-flowered, with terminal cupule and sometimes 1-many sessile, lateral cupules
• Male flowers : perianth tube campanulate; lobes 3-6, subtended by small bracteoles; stamens (2-)6(-12), surrounding tuft of silky hairs (apparently a reduced pistillode)
• Female flowers with smaller calyx, surrounded by an involucre of many imbricate or annular scales; ovary inferior, 3-locular; placentation axile; ovules 2 per locule, anatropous, crassinucellar, bitegmic; styles usually 3, short, recurved; stigmas broad, lining inner faces of styles
• Fruit a nut (acorn) arising on or partly enclosed by a cup-shaped or saucer-shaped cupule, involucral scales hardened into teeth or tubercles or annular lamellae
• Seed 1, without endosperm; embryo straight, as long as seed, cotyledons plano-convex
• x = 12 (aneuploids, polyploidy)

Nomenclature:

• *Quercus L.
  • Linnaeus: 994 (1753)
  • Linnaeus: 431 (1754)
  • Jussieu: 410 (1789)
  • Willdenow: 423 (1805)
  • Prantl: 47 (1889)
  • Camus (1936-1954)
  • Schwarz: 61 (1964)
  • Friis: 265 (1989)
  • Kubitzki: 308 (1993)
  • Nixon: 445 (1997)

Distribution & Notes:

• Global : Species ± 350-450; in the northern temperate and subtropical regions with extensions into the tropics in W Malesia and NW South America
• Southern Africa : Several species of * Quercus (Oaks), have been fairly extensively cultivated and at least 5 occur as escapes, notably * Quercus robur L. in the Western Cape