The Families of Flowering Plants
The Families of Flowering Plants | |
~ Verbenaceae
Habit and leaf form. Small mangrove trees and shrubs (branchlets articulate). Helophytic. Leaves opposite (decussate); leathery; simple. Lamina entire. Leaves exstipulate.
Leaf anatomy. Stomata diacytic.
Adaxial hypodermis present.
Stem anatomy. Internal phloem present. Secondary thickening anomalous; via concentric cambia. ‘Included’ phloem present. Xylem with libriform fibres. Vessel end-walls simple. Vessels without vestured pits. Wood parenchyma apotracheal.
Reproductive type, pollination. Plants hermaphrodite; viviparous.
Inflorescence, floral, fruit and seed morphology. Flowers aggregated in ‘inflorescences’; in cymes, in panicles, and in umbels. The terminal inflorescence unit cymose. Inflorescences terminal and axillary; cymose or thyrsiform, condensed or spiciform. Flowers bracteate; small; regular; cyclic; tetracyclic.
Perianth with distinct calyx and corolla; 9; 2 whorled; anisomerous. Calyx 5; 1 whorled; gamosepalous. Calyx lobes about the same length as the tube. Degree of gamosepaly (maximum length joined/total calyx length) about 0.5. Calyx slightly bilabiate; imbricate. Corolla 4; 1 whorled; gamopetalous. Corolla lobes about the same length as the tube, or markedly longer than the tube. Corolla imbricate; rotate, or campanulate; regular; yellow.
Androecium 4. Androecial members adnate (in the throat of the corolla); all equal to markedly unequal; free of one another; 1 whorled. Androecium exclusively of fertile stamens. Stamens 4; inserted in the throat of the corolla tube; didynamous (slightly), or not didynamous, not tetradynamous; isomerous with the perianth; oppositisepalous; alternating with the corolla members; filantherous to with sessile anthers. Anthers dehiscing via longitudinal slits; tetrasporangiate. Microsporogenesis simultaneous. Anther wall initially with more than one middle layer (up to three in A. officinalis). Tapetum glandular. Pollen grains aperturate; (2–)3 aperturate; colporate (colporoidate); 2-celled.
Gynoecium 2 carpelled. Carpels reduced in number relative to the perianth. The pistil imperfectly 4 celled. Gynoecium syncarpous; synstylovarious; superior. Ovary 2 locular. Locules partially secondarily divided by ‘false septa’. Styles 1. Ovules 2 per locule (one per locellus); pendulous; orthotropous to hemianatropous (the curvature arrested early, the ovule remaining almost orthotropous); unitegmic (but with incomplete growth of the integument, which does not form a micropyle); tenuinucellate. Endothelium not differentiated. Embryo-sac development Polygonum-type. Antipodal cells not formed (the 3 nuclei soon degenerating). Synergids hooked. Endosperm formation cellular. Endosperm haustoria present; chalazal and micropylar (of few cells). Embryogeny onagrad.
Fruit non-fleshy; dehiscent; a capsule. Capsules valvular (bivalved). Cotyledons 2. Embryo chlorophyllous.
Physiology, biochemistry. Not cyanogenic. Iridoids detected; ‘Route II’ type (normal and decarb.). Proanthocyanidins absent. Flavonols absent. Ellagic acid absent. C3. C3 physiology recorded directly in Avicennia. Anatomy non-C4 type (Avicennia).
Peculiar feature. Mangroves.
Geography, cytology. Tropical. Tropical coasts.
Taxonomy. Subclass Dicotyledonae; Tenuinucelli. Dahlgren’s Superorder Lamiiflorae; Lamiales. Cronquist’s Subclass Asteridae; Lamiales. APG (1998) Eudicot; core Eudicot; Asterid; Euasterid I; Lamiales. Species 11. Genera 1; only genus, Avicennia.
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 specified attributes, summaries of attributes within groups of taxa, geographical distribution, genera included in each family, classifications (Dahlgren; Dahlgren, Clifford, and Yeo; Cronquist; APG), and notes on the APG classification.
Cite this publication as: ‘Watson, L., and Dallwitz, M.J. 1992 onwards. The families of flowering plants: descriptions, illustrations, identification, and information retrieval. Version: 10th April 2008. http://delta-intkey.com’.