The families of flowering plants
Habit and leaf form. Trees. Leaves large; alternate; leathery; petiolate; non-sheathing; simple. Lamina entire; pinnately veined (above, though trinerved at the base, with a large pit in the axil of each of the basal laterals beneath); cross-venulate. Leaves stipulate. Stipules intrapetiolar; free of one another; caducous. Lamina margins entire.
Leaf anatomy. Stomata present; anomocytic.
Stem anatomy. Cortical bundles absent. Medullary bundles absent. Internal phloem absent. Secondary thickening developing from a conventional cambial ring. Included phloem absent. Xylem with fibre tracheids (sometimes septate); without libriform fibres. Vessel end-walls oblique; scalariform. Primary medullary rays mixed wide and narrow. Wood parenchyma apotracheal (diffuse).
Reproductive type, pollination. Plants hermaphrodite.
Inflorescence, floral, fruit and seed morphology. Flowers aggregated in inflorescences; in racemes, or in fascicles. Inflorescences axillary; axillary fascicles or clusters of small racemes. Flowers bracteolate (the bracteoles large, persistent); small; regular. Free hypanthium absent. Hypogynous disk present; intrastaminal (the stamens seated on or around it); cupulate or annular (multilobate).
Perianth sepaline (apetalous); 4–7; 1 whorled. Calyx 4–7 (hairy); 1 whorled; polysepalous; regular; imbricate (Cronquist), or valvate (Hutchinson).
Androecium 30–100 (many). Androecial members branched, or unbranched (?); maturing centrifugally (?); free of the perianth; free of one another, or coherent; when cohering, rather irregularly connate towards the base. Androecium exclusively of fertile stamens. Stamens 30–100 (many); polystemonous. Anthers dehiscing via longitudinal slits; introrse; unilocular (and small). Pollen shed as single grains. Pollen grains aperturate; 3 aperturate; colporate.
Gynoecium 3 carpelled, or 4 carpelled. Carpels reduced in number relative to the perianth to isomerous with the perianth. The pistil 1 celled. Gynoecium syncarpous; synovarious; superior, or partly inferior (half sunken into the disk in Peridiscus). Ovary 1 locular. Gynoecium stylate. Styles 3, or 4; free; short. Stigmas 3, or 4. Placentation apical. Ovules in the single cavity 6–8; pendulous.
Fruit fleshy; indehiscent; a drupe. The drupes with one stone. Fruit 1 seeded. Seeds abundantly endospermic (the endosperm horny, according to Cronquist), or non-endospermic (according to Hutchinson and Airy Shaw). Embryo well differentiated (small). Cotyledons 2. Embryo curved.
Geography, cytology. Neotropical. Tropical. Tropical South America.
Taxonomy. Subclass Dicotyledonae; Crassinucelli. Dahlgrens Superorder Violiflorae (or Malviflorae?); Violales (or Urticales?). Cronquists Subclass Dilleniidae; Violales. APG 3 core angiosperms; core eudicot; unplaced at Superordinal level; Order Saxifragales.
Species 2. Genera 2; Peridiscus, Whittonia.
General remarks. Not reliably classifiable, given the shortage of data and conflicting statements in the descriptions seen.
This description is offered for casual browsing only. We strongly advise against extracting comparative information from it. This is much more easily achieved using 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).
Cite this publication as: ‘Watson, L., and Dallwitz, M.J. 1992 onwards. The families of flowering plants: descriptions, illustrations, identification, and information retrieval. Version: 19th December 2012. http://delta-intkey.com’.