DELTA
home

The families of flowering plants

L. Watson and M. J. Dallwitz

Myricaceae Bl. & Dum.

Including Galeaceae Bubani

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. Leaf development not ‘graminaceous’.

Leaf anatomy. The leaf lamina dorsiventral, or dorsiventral to bifacial (tending to isobilateral in M. gale). 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). Adaxial hypodermis present, or absent. Minor leaf veins without phloem transfer cells (Myrica).

Axial (stem, wood) anatomy. Cork cambium present; initially superficial. Nodes tri-lacunar, or unilacunar (rarely). Primary vascular tissues comprising a ring of bundles (in the form of a lobed ring of slightly separated bundles); collateral. Internal phloem absent. Cortical bundles absent. Medullary bundles absent. Secondary thickening developing from a conventional cambial ring.

The wood diffuse porous. The vessels small (often very small); solitary, or radially paired and in radial multiples (typically exclusively solitary, but with few to numerous radial multiples in M. gale). The vessel end-walls scalariform, or simple, or scalariform and simple. The vessels without vestured pits; without spiral thickening. The axial xylem with fibre tracheids, or without fibre tracheids; with libriform fibres, or without libriform fibres (fibres typically with numerous distinctly bordered pits, but these less numerous and small-bordered in M. gale); without septate fibres. The fibres without spiral thickening. The parenchyma apotracheal (diffuse). The secondary phloem not stratified. ‘Included’ phloem absent. The wood not storied.

Reproductive type, pollination. Unisexual flowers present. 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).

Perianth absent (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. Styles 2; 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.

Seedling. Germination phanerocotylar. Nitrogen-fixing root nodules present (usually), or absent (Canacomyrica).

Physiology, phytochemistry. Not cyanogenic. Alkaloids absent (6 species). Iridoids not detected. Proanthocyanidins present; cyanidin and delphinidin. Flavonols present; kaempferol, quercetin, and myricetin. Ellagic acid present (Myrica). Sieve-tube plastids S-type.

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.

Quotations

I was of late as petty to his ends,
As is the morn-dew on the myrtle leaf
To his grand sea
(‘Antony and Cleopatra’, iii., 10)

Merciful heaven,
Thou rather, with thy sharp and sulphurous bolt,
Split’st the unwedgeable and gnarled oak,
Than the soft myrtle

Illustrations. • Technical details: Myrica, Comptonia. • Technical details: Myrica (Thonner). • Technical details: Comptonia (Lindley). • Myrica gale: Eng. Bot. 1298, 1868. • Myrica gale (B. Ent.).


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: 19th October 2016. delta-intkey.com’.

Contents