Francoaceae A. Juss.
~ Melianthaceae, Saxifragaceae sensu lato
Habit and leaf form. Glandular pilose or tomentose herbs. Perennial; more or less with a basal aggregation of leaves; rhizomatous. Leaves alternate; petiolate; more or less sheathing; simple. Lamina dissected, or entire; when simple, orbicular; when dissected, pinnatifid (to sub-pinnate); pinnately veined, or palmately veined; cross-venulate. Leaves exstipulate.
Leaf anatomy. Minor leaf veins without phloem transfer cells.
Reproductive type, pollination. Plants hermaphrodite.
Inflorescence, floral, fruit and seed morphology. Flowers aggregated in ‘inflorescences’; in racemes, or in panicles. The ultimate inflorescence unit racemose. Inflorescences scapiflorous; terminal; lax, elongate racemes or panicles. Flowers bracteate; regular, or very irregular; sometimes zygomorphic. The floral irregularity involving the perianth, or involving the androecium. Flowers more or less 4 merous; cyclic. Free hypanthium present to absent (the petals inserted at the base of the calyx).
Perianth with distinct calyx and corolla; (6–)8(–10); 2 whorled; isomerous, or anisomerous. Calyx 4(–5); 1 whorled; gamosepalous (slightly), or polysepalous. Calyx lobes markedly longer than the tube. Calyx persistent; valvate. Corolla 2, or (4–)5; 1 whorled; polypetalous; imbricate, or contorted; unequal but not bilabiate (with two petals smaller or missing), or regular. Petals clawed, or sessile.
Androecium 8, or 16. Androecial members free of the perianth; free of one another. Androecium including staminodes. Staminodes 4, or 8 (alternating with the stamens). Stamens 4, or 8; isomerous with the perianth, or diplostemonous. Anthers basifixed; versatile; dehiscing via longitudinal slits; latrorse. Pollen grains aperturate; 3 aperturate; colporate.
Gynoecium 2 carpelled (rarely), or 4 carpelled. Carpels reduced in number relative to the perianth, or isomerous with the perianth. The pistil 2 celled (rarely), or 4 celled. Gynoecium syncarpous; synstylovarious; superior. Ovary 2 locular (rarely), or 4 locular (with as many lobes); sessile. Gynoecium non-stylate (the stigmas sessile, globular or flattened). Stigmas 2 (rarely), or 4; commissural. Placentation axile. Ovules 20–50 per locule (‘many’); horizontal; biseriate; anatropous; bitegmic; crassinucellate. Outer integument contributing to the micropyle. Embryo-sac development Polygonum-type. Polar nuclei fusing prior to fertilization. Antipodal cells formed; 3; not proliferating; ephemeral. Synergids hooked. Endosperm formation nuclear.
Fruit non-fleshy; dehiscent; a capsule (erect). Capsules septicidal, or valvular. Fruit many seeded. Seeds endospermic; very small. Embryo minute.
Physiology, biochemistry. Proanthocyanidins absent. Flavonols absent. Ellagic acid present (strongly — Francoa).
Geography, cytology. Neotropical. Temperate. Chile.
Taxonomy. Subclass Dicotyledonae; Crassinucelli. Dahlgren’s Superorder Rosiflorae; Saxifragales. Cronquist’s Subclass Rosidae; Rosales. APG 3 core angiosperms; core eudicot; unplaced at Superordinal level; Order Geraniales (as a synonym of Melianthaceae?).
Species 2. Genera 2; Francoa, Tetilla.
• Technical details: Francoa.