Family Ticodendraceae

Ticodendraceae Gómes-Laurito and P. Gómes

Habit and leaf form. Trees (7–20 m tall). Leaves evergreen; alternate; somewhat distichous; subcoriacious; petiolate; non-sheathing; not gland-dotted; simple. Lamina entire; elliptic ovate (of fagacious aspect); pinnately veined; cross-venulate; cuneate at the base, or oblique at the base. Leaves stipulate. Stipules intrapetiolar; caducous. Lamina margins serrate (above).

Stem anatomy. Cork cambium present. Internal phloem absent. Secondary thickening developing from a conventional cambial ring. The secondary phloem not stratified. Xylem with tracheids; without fibre tracheids; without libriform fibres; with vessels. Vessel end-walls oblique; reticulately perforated and scalariform (with numerous bars). Vessels without vestured pits. Tile cells absent. Wood diffuse porous; parenchyma apotracheal (diffuse).

Reproductive type, pollination. Plants dioecious, or polygamodioecious (less commonly). Gynoecium of male flowers vestigial (rarely), or absent. Pollination anemophilous.

Inflorescence, floral, fruit and seed morphology. Flowers aggregated in ‘inflorescences’; in catkins. The ultimate inflorescence unit cymose (both male and female aments with some cymules on their primary axes. The male cymules borne verticillately in clusters of three, each cluster 1–3 flowered and subtended by a single bract; the female partial inflorescences solitary, each one-flowered but ‘reduced’, as evidenced by each being subtended by one primary bract, plus two secondary bracts with axillary scales). Inflorescences catkinlike, simple or branched, male or female, with partial inflorescences in the form of reduced cymules, the partial inflorescences and individual flowers not readily distinguishable without reference to their vasculature. Flowers bracteate; small.

Perianth vestigial (small, atop the ovary, in female flowers), or absent (in male flowers).

Androecium of male flowers 8–10 (or more?). Androecial members free of one another. Androecium exclusively of fertile stamens. Stamens 8–10 (or more?); shortly filantherous. Anthers basifixed; non-versatile; dehiscing via longitudinal slits; tetrasporangiate; appendaged. The anther appendages apical (short, by extension of the connective). Endothecium developing fibrous thickenings. Anther epidermis persistent. Pollen grains aperturate; 3 aperturate; porate; 2-celled.

Gynoecium 2 carpelled. The pistil 4 celled. Gynoecium syncarpous; synovarious; inferior. Ovary 4 locular. Epigynous disk absent. Gynoecium stylate. Styles 2(–3); free; apical. Stigmas 2(–3) (the styles stigmatic throughout). Placentation axile. Ovules 1 per locule; funicled; pendulous; hemianatropous; unitegmic; crassinucellate.

Fruit somewhat fleshy; indehiscent; a drupe (‘drupelike’, asymmetric, swollen on one side, greenish, mucilaginous). The drupes with one stone (the endocarp very hard, longitudinally furrowed). Fruit 1 seeded (three of the ovules degenerating). Seeds endospermic (the endosperm two-layered). Embryo well differentiated (massive). Cotyledons 2. Embryo straight.

Seedling. Germination cryptocotylar.

Geography, cytology. Neotropical. Central Mexico to southern Panama.

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 1. Genera 1; only known representative, Ticodendron incognitum.

Gómez-Laurito and Gómez (1991), Tobe (1991), Carlquist (1991).