The families of flowering plants
~ 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 units 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, phytochemistry. Proanthocyanidins absent. Flavonols absent. Ellagic acid present (strongly Francoa).
Geography, cytology. Neotropical. Temperate. Chile.
Taxonomy. Subclass Dicotyledonae; Crassinucelli. Dahlgrens Superorder Rosiflorae; Saxifragales. Cronquists 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.
General remarks. Differing conspicuously from Melianthaceae (q.v.) in numerous characters representing habit and leaf form, inflorescence and floral morphology (perianth, androecium, gynoecium and fruit), as well as in phytochemical records (no flavonols, seeds without amyloid).
Illustrations. • Francoa appendiculata: Bot. Mag. 59 (1832). • Technical details: Francoa.
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: 12th September 2017. delta-intkey.com/angio’.