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The families of flowering plants

L. Watson and M.J. Dallwitz

Fagaceae Dum.

Alternatively Cupuliferae A. Rich. (Is.str.), Cupulaceae Dulac

Including Nothofagaceae Kuprianova, Quercineae (Quercaceae) Juss.; excluding Corylaceae.

Habit and leaf form. Trees and shrubs; leptocaul. Mesophytic. Leaves evergreen, or deciduous; medium-sized; alternate; spiral, or distichous to four-ranked (rarely); ‘herbaceous’, or leathery; petiolate; non-sheathing; gland-dotted, or not gland-dotted; simple; epulvinate. Lamina dissected, or entire; when dissected, pinnatifid; pinnately veined; cross-venulate. Leaves stipulate. Stipules caducous. Lamina margins entire, or serrate, or dentate. Vegetative buds scaly. Leaf development not ‘graminaceous’. Domatia occurring in the family (from 3 genera); manifested as hair tufts (consistently).

Leaf anatomy. The leaf lamina dorsiventral to bifacial. Hydathodes present (occasionally), or absent. Mucilaginous epidermis present, or absent. Stomata mainly confined to one surface (abaxial); anomocytic. Hairs present (including a variety of types); eglandular and glandular (the former simple and unicellular, sometimes clustered so as to appear stellate; the latter variously uniseriate and tapered or capitate, or glandular-peltate). Adaxial hypodermis present (rarely), or absent. Lamina without secretory cavities. The mesophyll containing crystals. The crystals druses and solitary-prismatic. Minor leaf veins without phloem transfer cells (Nothofagus, Quercus).

Axial (stem, wood) anatomy. Secretory cavities absent. Cork cambium present; initially superficial. Nodes tri-lacunar. Primary vascular tissues in a cylinder, without separate bundles (but the xylem sometimes dissected by broad, lignified primary rays); collateral. Internal phloem absent. Cortical bundles absent. Medullary bundles absent. Secondary thickening developing from a conventional cambial ring. Primary medullary rays wide, or mixed wide and narrow, or narrow.

The wood ring porous, or semi-ring porous, or diffuse porous. The vessels small to medium, or large (sometimes more than 200 microns when diffuse porous); variously solitary, or radially paired, or in radial multiples, or clustered, or in tangential arcs. The vessel end-walls scalariform, or scalariform and simple. The vessels without vestured pits; with spiral thickening, or without spiral thickening. The axial xylem with tracheids; with vasicentric tracheids (commonly), or without vasicentric tracheids (Fagus and Nothofagus); with fibre tracheids to without fibre tracheids; with libriform fibres, or without libriform fibres; including septate fibres, or without septate fibres. The fibres without spiral thickening. The parenchyma apotracheal (diffuse or in fine lines). The secondary phloem stratified into hard (fibrous) and soft (parenchymatous) zones, or not stratified. ‘Included’ phloem absent. The wood partially storied (VR, Nothofagus), or not storied. Tyloses present, or absent.

Reproductive type, pollination. Plants monoecious (nearly always), or dioecious (rarely). Gynoecium of male flowers pistillodial to absent. Pollination anemophilous (usually), or entomophilous (e.g. Castanea).

Inflorescence, floral, fruit and seed morphology. Flowers solitary, or aggregated in ‘inflorescences’; when solitary, axillary; when aggregated, in catkins (usually, at least the males), or in heads, or in glomerules. The ultimate inflorescence units cymose. Inflorescences when flowers aggregated, axillary; with male flowers usually in more or less reduced dichasia aggregated into aments or distributed along a branching axis, the females in 1–7(–15)-flowered clusters at the bases of these or in separate few-flowered inflorescences; with involucral bracts. The involucres accrescent (and sometimes cupular, subtending the fruit or sometimes enclosing it). Flowers bracteate; minute. Free hypanthium absent.

Perianth sepaline, or vestigial; (4–)6(–7); free to joined; 1 whorled. Calyx (if the perianth is so interpreted) (4–)6(–7) (in the form of small scales); polysepalous, or gamosepalous; blunt-lobed; regular; in male flowers imbricate.

Androecium (4–)6–12(–40) (in male flowers). Androecial members free of the perianth; all equal; free of one another; 1 whorled (or more when numerous?). Androecium exclusively of fertile stamens. Stamens (4–)6–12(–40); isomerous with the perianth to diplostemonous to polystemonous; oppositisepalous, or alternisepalous and oppositisepalous. Anthers dehiscing via longitudinal slits. Pollen grains aperturate; 3 aperturate, or 4–7 aperturate; colpate, or colporate; 2-celled.

Gynoecium (2–)3 carpelled (usually), or 6(–12) carpelled. The pistil (2–)3 celled (usally), or 6(–12) celled. Gynoecium syncarpous; synovarious; inferior. Ovary (2–)3 locular (usually), or 6(–12) locular (but the septa falling short of the one-locular apex). The ‘odd’ carpel when G3 anterior. Styles (2–)3 (usually), or 6(–12) (as many as the locules); free; apical. Stigmas dry type; non-papillate; Group II type. Placentation axile, or apical. Ovules 2 per locule; pendulous; non-arillate; anatropous; bitegmic (usually), or unitegmic (Nothofagus); crassinucellate. Embryo-sac development Polygonum-type. Polar nuclei fusing prior to fertilization. Antipodal cells formed; 3; proliferating (sometimes), or not proliferating. Synergids sometimes with filiform apparatus. Endosperm formation nuclear. Embryogeny onagrad.

Fruit non-fleshy; indehiscent (subtended by the accrescent involucre, which sometimes encloses it before opening like a pericarp); a nut (with stony or leathery pericarp), or a samara (rarely); usually 1 seeded (by abortion). Seeds non-endospermic. Seeds with starch. Cotyledons 2. Embryo achlorophyllous (3/8).

Seedling. Germination phanerocotylar (e.g. Fagus), or cryptocotylar (e.g. Castanea).

Physiology, phytochemistry. C3. C3 physiology recorded directly in Quercus. Sugars transported as sucrose, or as oligosaccharides + sucrose, or as sugar alcohols + oligosaccharides + sucrose (but sucrose always predominating, in 29 species from 3 genera). Not cyanogenic. Alkaloids present (very rarely), or absent. Arbutin absent. Iridoids not detected. Proanthocyanidins present (mostly), or absent; when present, cyanidin, or cyanidin and delphinidin. Flavonols present; quercetin, or kaempferol and quercetin, or kaempferol, quercetin, and myricetin. Ellagic acid present (mostly), or absent (4 genera listed). Aluminium accumulation demonstrated (perhaps, in Quercus spp.), or not found (mostly).

Geography, cytology. Frigid zone, temperate, and sub-tropical. Cosmopolitan, except tropical South America and tropical and South Africa. X = (11-)12(-13).

Taxonomy. Subclass Dicotyledonae; Crassinucelli. Dahlgren’s Superorder Rosiflorae; Fagales. Cronquist’s Subclass Hamamelidae; Fagales. APG 3 core angiosperms; core eudicot; Superorder Rosanae; fabid; Order Fagales.

Species about 900. Genera 9; Fagus, Nothofagus, Lithocarpus, Castanopsis, Colombobalanus, Castanea, Chrysolepis, Quercus, Trigonobalanus.

Economic uses, etc. Important sources of hardwood timber (oak, beech, chestnut), chestnuts (Castanea), and (from Quercus) cork and tannins.


And many strokes, though with a little axe,
Hew down and fell the hardest-timbered oak
(‘3rd Henry the Sixth’, ii., 1)

He lay along,
Under an oak whose antique roots peep out
Upon the brook that brawls along this wood
(‘As You Like It’, ii., 1) ;

(An oak . .) Whose boughs were moss’d with age,
And high top bald with dry antiquity
(‘As You Like It’, iv., 3)

I have seen tempests when the scolding winds
Have rived the knotty oaks
(‘Julius Caesar’, i., 3)

All the elves for fear,
Creep into acorn-cups, and hide them there
(‘Midsummer Night’s Dream’, i., 1)

Sweet chestnuts brown, like soleing leather turn,
(John Clare c.1850, ‘The Winter’s Come’ — Castanea)

Illustrations. • Fagus sylvatica: Eng. Bot. 1291, 1868. • Quercus robur (as Q. pedunculata) and Q. petraea (as Q. sessiliflora): Eng. Bot. 1288 and 1289, 1868. • Quercus lamellosa: Hooker’s Illustrations of Himalayan plants (1855). • Lithocarpus lappaceus, as Quercus mackeana: Hook. Ic. Pl. 3 (1840). • Le Maout and Decaisne: Castanea, Fagus. • Le Maout and Decaisne: Quercus. • Castanea sativa (as C. vulgaris): Eng. Bot. 1290, 1868. • Castanopsis indica, as Castanea: R. Wight, Ic. Pl. Indiae Orientalis 2 (1843). • Lithocarpus beccarianus, as Quercus: Hook. Ic. Pl. 14 (1880–82). • Nothofagus antarctica (as Fagus): Hooker, Fl. Antarctica (1844). • Nothofagus betuloides (as Fagus): Hooker, Fl. Antarctica (1844). • Nothofagus fusca, as Fagus: Hook. Ic. Pl. 7–8 (1844). • Colombobalanus (R.E Halling, photo). • Fagus sylvatica (B. Ent., 1838).

We advise against extracting comparative information from the descriptions. This is much more easily achieved using the DELTA data files or the interactive key, which allows access to the character list, illustrations, full and partial descriptions, diagnostic descriptions, differences and similarities between taxa, lists of taxa exhibiting or lacking specified attributes, distributions of character states within any set of taxa, geographical distribution, genera included in each family, and classifications (Dahlgren; Dahlgren, Clifford, and Yeo; Cronquist; APG). See also Guidelines for using data taken from Web publications.

Cite this publication as: ‘Watson, L., and Dallwitz, M.J. 1992 onwards. The families of flowering plants: descriptions, illustrations, identification, and information retrieval. Version: 24th October 2017.’.