Habit and leaf form. Trees, or shrubs, or lianas; not resinous. Leaves opposite, or whorled; petiolate; simple. Lamina dissected, or entire; when dissected, pinnatifid (lobed); pinnately veined. Leaves stipulate. Stipules interpetiolar; rigid or foliaceous. Lamina margins entire, or crenate.
Leaf anatomy. Stomata present; paracytic.
Lamina dorsiventral; with secretory cavities. Secretory cavities containing mucilage; lysigenous. The mesophyll containing calcium oxalate crystals. The mesophyll crystals druses and solitary-prismatic.
Stem anatomy. The cortex containing cristarque cells. Nodes tri-lacunar. Internal phloem absent. Secondary thickening developing from a conventional cambial ring. ‘Included’ phloem absent. Xylem with tracheids; with vessels. Vessel end-walls simple (usually), or scalariform. Wood parenchyma apotracheal.
Reproductive type, pollination. Plants hermaphrodite, or polygamomonoecious, or polygamodioecious.
Inflorescence, floral, fruit and seed morphology. Flowers aggregated in ‘inflorescences’; in racemes, or in panicles. Inflorescences terminal, or axillary; panicles or racemes. Flowers small; regular, or somewhat irregular.
Perianth with distinct calyx and corolla; 8–10(–13); 2 whorled; isomerous, or anisomerous. Calyx 4, or 5; 1 whorled; polysepalous (the sepals small); unequal but not bilabiate; imbricate. Corolla 4–5(–8); 1 whorled; imbricate, or contorted.
Androecium 15–30, or 30–170 (to ‘many’). Androecial members free of the perianth, or adnate (to the corolla, below); free of one another, or coherent (below). Androecium exclusively of fertile stamens. Stamens 15–30, or 30–170; triplostemonous, or polystemonous. Anthers basifixed (small); non-versatile; dehiscing via longitudinal slits; introrse (the thecae sharply distinct), or latrorse (the thecae back to back and latrorse, Froesia); bilocular; tetrasporangiate. Pollen grains aperturate; 3 aperturate; colporate.
Gynoecium 2–3 carpelled, or 3 carpelled, or 7–11(–13) carpelled. Carpels reduced in number relative to the perianth to increased in number relative to the perianth. The pistil when syncarpous, 2–3 celled, or 7–11(–13) celled. Gynoecium apocarpous (Froesia), or syncarpous; eu-apocarpous (Froesia, with three distinct carpels), or synovarious; superior. Carpel in Froesia stylate; 2 ovuled. Ovary when syncarpous, 2–3 locular, or 7–11(–13) locular (reflecting the carpel number). Gynoecium stylate. Styles 2–3, or 7–11(–13) (one per carpel); free (linear). Stigmas 2–3, or 7–11(–13); obliquely peltate. Placentation when syncarpous, basal to axile. Ovules 2 per locule; ascending; anatropous.
Fruit fleshy. The fruiting carpel in Froesia, dehiscent, or indehiscent (?); baccate. Fruit dehiscent (at full maturity), or indehiscent; a capsule (baccate), or a berry. Capsules when dehiscent, valvular. Fruit usually only 1–4 seeded (often only 1–2 locular through abortion of the others). Seeds non-endospermic; conspicuously hairy (usually, tomentose), or not conspicuously hairy (Froesia). Embryo well differentiated. Cotyledons 2 (thick). Embryo straight.
Seedling. Germination cryptocotylar.
Physiology, biochemistry. Not cyanogenic.
Geography, cytology. Neotropical. Tropical. Tropical South America.
Taxonomy. Subclass Dicotyledonae; Crassinucelli (? — stipules, polypetalous, etc.). Dahlgren’s Superorder Theiflorae; Theales. Cronquist’s Subclass Dilleniidae; Theales. APG 3 core angiosperms; core eudicot; Superorder Rosanae; fabid; Order Malpighiales (as a synonym of Ochnaceae?).
Species 50. Genera 4; Froësia, Lacunaria, Quiina, Touroulia.