The families of flowering plants.
Habit and leaf form. Trees, or shrubs; resinous. Leaves evergreen, or deciduous; alternate (to subopposite); spiral (often with 2/5 phyllotaxy); petiolate; non-sheathing; aromatic; simple. Lamina dissected (Comptonia), or entire; when dissected, pinnatifid; pinnately veined; cross-venulate. Leaves stipulate (Comptonia only), or exstipulate (usually). Lamina margins entire, or serrate, or dentate. Leaves without a persistent basal meristem.
Leaf anatomy. Stomata present; mainly confined to one surface (abaxial); anomocytic. Hairs present; eglandular and glandular; unicellular and multicellular. Complex hairs present; peltate (mostly with characteristic, peltate glands secreting aromatic, waxy material).
Lamina dorsiventral. Minor leaf veins without phloem transfer cells (Myrica).
Stem anatomy. Cork cambium present; initially superficial. Nodes tri-lacunar, or unilacunar (rarely). Internal phloem absent. Secondary thickening developing from a conventional cambial ring. ‘Included’ phloem absent. Xylem with tracheids, or without tracheids (Gale); with fibre tracheids (Gale), or without fibre tracheids; with vessels. Vessel end-walls scalariform, or simple, or scalariform and simple. Wood parenchyma apotracheal (diffuse). Sieve-tube plastids S-type.
Reproductive type, pollination. Unisexual flowerspresent. Plants monoecious, or andromonoecious, or dioecious, or androdioecious (?). Gynoecium of male flowers pistillodial (Canacomyrica), or vestigial to absent. Pollination anemophilous.
Inflorescence, floral, fruit and seed morphology. Flowers aggregated in ‘inflorescences’; in spikes (simple or compound). Inflorescences axillary; short, catkin-like simple or compound spikes. Flowers bracteate; bracteolate (males usually with 2 bracteoles, females with 2–4, these commonly accrescent and enclosing the fruit); small (and inconspicuous); cyclic. Hypogynous disk present (male flowers), or absent (female flowers); annular (sinuate).
Perianthabsent (except possibly in the monotypic Canacomyrica, which has an accrescent structure, interpretable as disk, bracteoles or perianth, which develops to enclose the fruit).
Androecium in male or hermaphrodite flowers, (2–)4(–6). Androecial members free of one another, or coherent (the filaments sometimes connate); when joined, 1 adelphous; 1 whorled. Androecium exclusively of fertile stamens. Stamens(2–)4(–6). Anthers dehiscing via longitudinal slits; extrorse; tetrasporangiate. Microsporogenesis simultaneous. Pollen grains aperturate; (2–)3(–6) aperturate; porate; 2-celled.
Gynoecium 2 carpelled. The pistil 1 celled. Gynoecium syncarpous; synovarious to synstylovarious (the styles distinct or basally united); superior (usually), or partly inferior (hermaphrodite flowers of Canacomyrica, with perigynous stamens). Ovary 1 locular; sessile. Gynoecium stylate. Styles2; free to partially joined; apical. Stigmas 2; dry type; non-papillate; Group II type. Placentation basal. Ovules in the single cavity 1; ascending; orthotropous (but Canacomyrica with a reflexed prolongation of the integument, resembling a funiculus); unitegmic; crassinucellate. Embryo-sac development Polygonum-type. Polar nuclei fusing prior to fertilization. Antipodal cells formed; 3; not proliferating; ephemeral. Synergids pear-shaped. Endosperm formation nuclear.
Fruit fleshy to non-fleshy; indehiscent; a drupe (often waxy-warted, sometimes almost a nut). Capsules sometimes enveloped by persistent, accrescent bracteoles which form a burr-like cupule in Comptonia, and which in Gale develop only late into a pair of floats which fall with the fruit. The drupes with one stone. Seeds scantily endospermic, or non-endospermic. Embryo well differentiated. Cotyledons 2; plano-convex. Embryo straight.
Physiology, biochemistry. Nitrogen-fixing root nodules present (usually), or absent (Canacomyrica). Not cyanogenic. Alkaloids absent (6 species). Iridoids not detected. Proanthocyanidins present; cyanidin and delphinidin. Flavonols present; kaempferol, quercetin, and myricetin. Ellagic acid present (Myrica).
Geography, cytology. Temperate to tropical. Very widespread, but lacking in North Africa, most of temperate Eurasia and Australasia. X = 8.
Taxonomy.Subclass Dicotyledonae; Crassinucelli. Dahlgren’s Superorder Rosiflorae; Myricales. Cronquist’s Subclass Hamamelidae; Myricales. APG 3 core angiosperms; core eudicot; Superorder Rosanae; fabid; Order Fagales.
Species 40. Genera 4; Canacomyrica(?), Comptonia, Gale and Myrica (all but the latter mono- or ditypic).
Economic uses, etc. Myrica species are the source of aromatic wax (from the fruits, used to make bayberry candles), of edible fruit, and of tannic acid.