The families of flowering plants
Habit and leaf form. Small trees, or shrubs (scrambling). Leaves alternate; not gland-dotted; simple. Lamina entire. Leaves exstipulate.
Leaf anatomy. The leaf lamina dorsiventral. Stomata mainly confined to one surface (abaxial); anomocytic. Adaxial hypodermis of several layers present. The mesophyll with sclerenchymatous idioblasts (these rounded, with short arms).
Axial (stem, wood) anatomy. Pith heterogeneous (with solitary and grouped sclerosed cells). Secretory cavities present (?). Cork cambium present; initially superficial. Nodes unilacunar. Primary vascular tissues in a cylinder, without separate bundles; collateral. Internal phloem absent. Cortical bundles absent. Medullary bundles absent. Secondary thickening developing from a conventional cambial ring. Primary medullary rays narrow (wood rays all uniseriate).
The wood diffuse porous. The vessels small; mostly solitary. The vessel end-walls simple. The axial xylem without tracheids; with libriform fibres. The parenchyma paratracheal.
Reproductive type, pollination. Plants hermaphrodite.
Inflorescence, floral, fruit and seed morphology. Flowers aggregated in inflorescences; in panicles. The ultimate inflorescence units cymose. Inflorescences terminal, or axillary; many-flowered thyrses. Flowers regular; cyclic. Free hypanthium absent.
Perianth with distinct calyx and corolla; 10; 2 whorled; isomerous. Calyx 5; 1 whorled; polysepalous; regular; persistent; accrescent; imbricate. Corolla 5; 1 whorled; polypetalous (the petals narrow); imbricate; regular; deciduous.
Androecium 9–15. Androecial members free of the perianth; coherent (connate below into a more or less broad ring); 1 adelphous. Androecium exclusively of fertile stamens. Stamens 9–15 (the filaments persistent); diplostemonous to triplostemonous. Anthers dorsifixed; versatile (small, deciduous); dehiscing via longitudinal slits; tetrasporangiate. Pollen grains aperturate; 3 aperturate; colpate, or colporate (colporoidate).
Gynoecium (2–)3 carpelled. Carpels reduced in number relative to the perianth. The pistil (2–)3 celled. Gynoecium syncarpous; synovarious, or synstylovarious, or eu-syncarpous (the single style shortly 3-lobed at the apex, with three short, reflexed styles, or intermediate); superior. Ovary (2–)3 locular. Gynoecium stylate. Styles 1, or 3; when three, free to partially joined; apical. Placentation axile. Ovules 2–50 per locule (to many); pendulous; anatropous; bitegmic.
Fruit non-fleshy; indehiscent; capsular-indehiscent (thick walled, surrounded by the persistent staminal filaments and winged by the accrescent, leathery or membranous calyx). Dispersal unit the flower (i.e. its remains). Fruit 2–50 seeded (to many). Seeds non-endospermic.
Geography, cytology. Paleotropical. Tropical. Madagascar.
Taxonomy. Subclass Dicotyledonae; Tenuinucelli. Dahlgrens Superorder Theiflorae (by inference); Theales. Cronquists Subclass Dilleniidae; Theales. APG 3 core angiosperms; core eudicot; Superorder Caryophyllanae; Order Caryophyllales.
Species 7. Genera 1; only genus, Asteropeia.
Illustrations. • Asteropeia amblyocarpa and A. densiflora: Perrier in Flore de Madagascar (1951). • Asteropeia micraster, A. rhopaloides and A. angustata: Perrier in Flore de Madagascar (1951).
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: 13th March 2017. delta-intkey.com/angio’.