Including Monandrodendraceae Barkley
Habit and leaf form. Small trees, or shrubs. Plants non-succulent. Leaves alternate; distichous; simple. Lamina dissected (toothed), or entire. Leaves stipulate. Stipules caducous (small).
Leaf anatomy. Stomata present; mainly confined to one surface (abaxial); anomocytic.
Lamina dorsiventral. The mesophyll containing calcium oxalate crystals. The mesophyll crystals druses.
Stem anatomy. Cork cambium present; initially superficial. Secondary thickening developing from a conventional cambial ring. Xylem with libriform fibres (septate). Vessel end-walls scalariform. Wood parenchyma apotracheal (diffuse).
Reproductive type, pollination. Unisexual flowers absent. Plants hermaphrodite (mostly).
Inflorescence, floral, fruit and seed morphology. Flowers aggregated in ‘inflorescences’; in racemes, or in spikes, or in catkins. Inflorescences axillary; catkinlike — small, dense, cylindrical, fascicled axillary spikes or racemes. Flowers bracteate (the bracts small and inconspicuous (Lozania) or conspicuous and imbricate (Lacistema)); bi- bracteolate; very small, or minute. Floral receptacle markedly hollowed (expanded into a fleshy, concave disk).
Perianth sepaline, or absent; 0, or 4–6. Calyx when present, 4–6; polysepalous; members unequal.
Androecium 1. Androecial members free of the perianth. Androecium exclusively of fertile stamens. Stamens 1. Anthers dehiscing via longitudinal slits; bilocular (the locules separate, sometimes stipitate). Pollen shed as single grains. Pollen grains aperturate; 3 aperturate; colporate.
Gynoecium 2–3 carpelled. The pistil 1 celled. Gynoecium syncarpous; synstylovarious; superior. Ovary 1 locular. Gynoecium stylate. Styles 1. Stigmas 2–3 (distinct). Placentation parietal. Ovules in the single cavity 2–6 (with 1–2 ovules on each placenta); pendulous; anatropous; bitegmic; crassinucellate. Endosperm formation nuclear.
Fruit non-fleshy; dehiscent; a capsule. Capsules three valvular. Fruit 1 seeded. Seeds endospermic. Endosperm oily. Embryo well differentiated. Cotyledons 2; flat (broad, foliar). Embryo straight.
Geography, cytology. Neotropical. Sub-tropical to tropical. Tropical America, West Indies.
Taxonomy. Subclass Dicotyledonae; Crassinucelli. Dahlgren’s Superorder Violiflorae; Violales (cf. Flacourtiaceae). Cronquist’s Subclass Dilleniidae; Violales. APG 3 core angiosperms; core eudicot; Superorder Rosanae; fabid; Order Malpighiales.
Species 27. Genera 2; Lacistema, Lozania.
• Technical details: Lacistema (Lindley).