The families of flowering plants.
Habit and leaf form. Trees, or shrubs. Plants non-succulent. 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. Leaves without a persistent basal meristem. Vernation plicate (the folds parallel with the lateral nerves). Domatia occurring in the family (from two genera); manifested as hair tufts.
Leaf anatomy. Stomata anomocytic.
Lamina dorsiventral. Minor leaf veins without phloem transfer cells (Carpinus).
Stem anatomy. Cork cambium present; initially arising in the outer cortex. Nodes tri-lacunar. Internal phloem absent. Secondary thickening developing from a conventional cambial ring. The secondary phloem stratified into hard (fibrous) and soft (parenchymatous) zones. ‘Included’ phloem absent. Xylem with vessels. Vessel end-walls simple. Vessels without vestured pits. Wood ring porous; parenchyma apotracheal. Sieve-tube plastids S-type.
Reproductive type, pollination. Plantsmonoecious. 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 unit 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.
Perianthsepaline (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.
Gynoecium2 carpelled. The pistil 2 celled. Gynoecium syncarpous; synovarious, or synstylovarious; inferior. Ovary 2 locular. Gynoeciumtransverse. 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.
Physiology, biochemistry. Flavonols present; kaempferol, quercetin, and myricetin. Ellagic acid present (Carpinus). C3. C3 physiology recorded directly in Ostrya.
Geography, cytology. Holarctic and Neotropical. Temperate. North temperate.
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 (as a synonym of Betulaceae).
Species 47. Genera 3; Carpinus, Ostrya, Ostryopsis.