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The families of flowering plants

L. Watson and M.J. Dallwitz

Carpinaceae (Spach) Kuprianova

~ Betulaceae.

Habit and leaf form. Trees, or shrubs; leptocaul. Mesophytic. Leaves deciduous; medium-sized; alternate; spiral to distichous; flat; petiolate; non-sheathing; simple. Lamina entire; pinnately veined (the laterals straight); cross-venulate. Leaves stipulate. Stipules intrapetiolar; free of one another; caducous. Lamina margins serrate, or dentate; flat. Vegetative buds scaly. Leaf development not ‘graminaceous’. Vernation plicate (the folds parallel with the lateral nerves). Domatia occurring in the family (from two genera); manifested as hair tufts.

Leaf anatomy. The leaf lamina dorsiventral. Stomata mainly confined to one surface (abaxial); anomocytic. Hairs present; eglandular and glandular (the former unicellular and/or uniseriate, the latter variously spherical, ellipsoidal and disc-shaped). Minor leaf veins without phloem transfer cells (Carpinus).

Axial (stem, wood) anatomy. Cork cambium present; arising in the outer cortex. Nodes tri-lacunar. Primary vascular tissues in a cylinder, without separate bundles; collateral. Internal phloem absent. Cortical bundles absent. Medullary bundles absent. Secondary thickening developing from a conventional cambial ring. Primary medullary rays narrow.

The wood ring porous to diffuse porous. The vessels small. The vessel end-walls simple, or scalariform, or scalariform and simple. The vessels without vestured pits. The axial xylem with fibre tracheids to without fibre tracheids; with libriform fibres to without libriform fibres (the fibres with rather fer, small-bordered pits); without septate fibres. The fibres without spiral thickening. The parenchyma apotracheal. The secondary phloem stratified into hard (fibrous) and soft (parenchymatous) zones. ‘Included’ phloem absent. The wood not storied.

Reproductive type, pollination. Plants monoecious. Gynoecium of male flowers absent. Pollination anemophilous.

Inflorescence, floral, fruit and seed morphology. Flowers aggregated in ‘inflorescences’; in catkins (the female catkins terminal, the males representing short-shoots). The ultimate inflorescence units cymose (the female catkins with three-flowered cymules or with the central member absent, the males uninterpretable in the absence of bracteoles). Inflorescences different in form: the male catkins with bracts but no bracteoles and the flowers non-involucrate, the female flowers each with a large, membranous involucre formed of the bract and two bracteoles. Flowers bracteate; bracteolate (female), or ebracteolate (male); small.

Perianth sepaline (female), or absent (male); 1 whorled.

Androecium 4–12. Androecial members branched (often split almost to their bases), or unbranched. Androecium exclusively of fertile stamens. Stamens 4–12. Anthers dehiscing via longitudinal slits; bilocular (the locules more or less separate); tetrasporangiate. Pollen shed as single grains. Pollen grains aperturate; 3–5 aperturate; porate (without arci, the pores operculate or plugged); 2-celled.

Gynoecium 2 carpelled. The pistil 2 celled. Gynoecium syncarpous; synovarious, or synstylovarious; inferior. Ovary 2 locular. Gynoecium transverse. Epigynous disk absent. Gynoecium stylate. Styles 2; free, or partially joined; apical. Stigmas dry type; papillate; Group II type. Placentation axile to apical. Ovules 1 per locule; funicled; pendulous (from near the top of the septum); anatropous; bitegmic; crassinucellate. Outer integument not contributing to the micropyle. Endosperm formation nuclear.

Fruit non-fleshy; indehiscent; a nut (small, 1-seeded, shed with the accrescent, trilobed ‘involucre’). Seeds non-endospermic. Embryo well differentiated. Cotyledons 2. Embryo straight. Micropyle not zigzag.

Seedling. Germination phanerocotylar.

Physiology, phytochemistry. C3. C3 physiology recorded directly in Ostrya. Flavonols present; kaempferol, quercetin, and myricetin. Ellagic acid present (Carpinus). Sieve-tube plastids S-type.

Geography, cytology. Holarctic and Neotropical. Temperate. North temperate.

Taxonomy. Subclass Dicotyledonae; Crassinucelli. Dahlgren’s Superorder Rosiflorae; Fagales. Cronquist’s Subclass Hamamelidae; Fagales. APG III core angiosperms; core eudicot; Superorder Rosanae; fabid. APG IV Order Fagales (as a synonym of Betulaceae).

Species 47. Genera 3; Carpinus, Ostrya, Ostryopsis.

General remarks. Seemingly differing from Betulaceae sensu stricto (q.v.) in the stratified secondary phloem, as well as in the superior ovary and other details of the gynoecium and ovules.


In time it waxeth so hard that the toughnesse and hardnesse of it may be rather compared to horn than unto wood
(Hence ‘Hornbeam’. Gerarde’s ‘Herball’, 1597)

Illustrations. • Le Maout and Decaisne: Carpinus. • Carpinus betulus: B. Ent. 579, 1836. • Carpinus betulus: Eng. Bot. 1293, 1868.

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: 15th April 2018.’.