The families of flowering plants
Including Tripterelleae (Tripterellaceae) Dum.; excluding Corsiaceae, Thismiaceae.
Habit and leaf form. Herbs. Normal plants, or plants of very peculiar vegetative form (some being tiny saprophytes); sometimes vegetatively almost filamentous, or fungoid. Leaves well developed, or much reduced, or absent. Plants autotrophic, or saprophytic. Annual, or perennial; with a basal aggregation of leaves, or without conspicuous aggregations of leaves. Leaves alternate; spiral (usually), or distichous; herbaceous, or membranous; sessile; sheathing. Leaf sheaths with free margins. Leaves simple. Lamina entire; usually linear to ovate; parallel-veined; without cross-venules.
General anatomy. Plants without silica bodies.
Leaf anatomy. Stomata anomocytic. The mesophyll containing crystals (sometimes?), or without crystals. The crystals if present, not raphides. Foliar vessels present (in some autotrophic taxa), or absent; with scalariform end-walls.
Axial (stem, wood) anatomy. Secondary thickening absent. The axial xylem with vessels (in some autotrophs), or without vessels.
The vessel end-walls scalariform.
Root anatomy. Roots with velamen, or without velamen. Root xylem with vessels; vessel end-walls scalariform.
Reproductive type, pollination. Plants hermaphrodite, or monoecious. Floral nectaries present. Nectar secretion from the gynoecium (via septal nectaries, or from the top or sides of the ovary).
Inflorescence, floral, fruit and seed morphology. Flowers solitary, or aggregated in inflorescences; when aggregated, in cymes, or in racemes. The ultimate inflorescence units cymose. Inflorescences terminal; dichasia or monochasia. Flowers regular; 3 merous; cyclic; tetracyclic. Perigone tube present (3-winged).
Perianth of tepals; 6, or 3 (3+3, but either whorl may be reduced or obsolete); joined; 1 whorled, or 2 whorled; isomerous; petaloid; different in the two whorls (Burmannia with the inner lobes smaller or absent), or similar in the two whorls.
Androecium 3. Androecial members adnate (to the tube); free of one another; 1 whorled. Androecium exclusively of fertile stamens. Stamens 3; isomerous with the perianth; when perianth developed, oppositiperianthial (by contrast with Iridaceae etc.). Anthers introrse to latrorse; tetrasporangiate; appendaged (often), or unappendaged. Microsporogenesis successive. Anther wall initially with one middle layer. Tapetum probably glandular. Pollen shed as single grains. Pollen grains aperturate, or nonaperturate; 1 aperturate; when aperturate, sulcate, or ulcerate; 3-celled (Apteria), or 2-celled and 3-celled (with both conditions recorded in Burmannia), or 3-celled.
Gynoecium 3 carpelled. Carpels isomerous with the perianth. The pistil 1 celled, or 3 celled. Gynoecium syncarpous; synstylovarious; partly inferior. Ovary 1 locular, or 3 locular. Styles 1; partially joined; apical. Stigmas 3. Placentation when unilocular parietal; when trilocular axile. Ovules in the single cavity when unilocular, 15–100 (? many); when trilocular 10–50 per locule (? many); anatropous; bitegmic; tenuinucellate. Embryo-sac development Polygonum-type, or Allium-type. Polar nuclei fusing prior to fertilization. Antipodal cells formed; 3; not proliferating; small. Synergids pear-shaped. Endosperm formation cellular, or helobial. Embryogeny onagrad, or asterad (?).
Fruit non-fleshy; dehiscent; a capsule. Capsules splitting irregularly, or loculicidal, or valvular (rarely). Fruit 15–100 seeded (many). Seeds scantily endospermic; winged. Embryo rudimentary at the time of seed release. Testa without phytomelan; thin.
Physiology, phytochemistry. Accumulated starch other than exclusively pteridophyte type. Saponins/sapogenins possibly present, extracts being haemolytic.
Geography, cytology. Holarctic, Paleotropical, Neotropical, Australian, and Antarctic. Temperate to tropical. Widespread, tropical, subtropical, north to Japan and eastern U.S.A., south to Tasmania and New Zealand.
Taxonomy. Subclass Monocotyledonae. Dahlgren et al. Superorder Liliiflorae; Burmanniales. APG 3 core angiosperms; Superorder Lilianae; non-commelinid Monocot; Order Dioscoreales.
Species 125. Genera 9; Apteria, Burmannia, Campylosiphon, Cymbocarpa, Dictyostega, Gymnosiphon, Hexapterella, Marthella, Miersiella.
Illustrations. • Apteria, Burmannia, Campylosiphon, Dictyostegia: Nat. Pflanzenfam. II (1889). • Technical details: Burmannia, Apteria. • Technical details: Dictyostega (Lindley.
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: 19th October 2016. delta-intkey.com’.