The Families of Flowering Plants
The Families of Flowering Plants | |
~ Acanthaceae
Habit and leaf form. Lianas (with articulated young stems). Leaves opposite; simple. Lamina entire. Leaves exstipulate. Lamina margins entire.
Leaf anatomy. Stomata present; diacytic. Hairs present; eglandular and glandular (cf. Acanthaceae).
Lamina without secretory cavities. Cystoliths absent.
Stem anatomy. Secretory cavities absent. Internal phloem absent. Secondary thickening anomalous; via concentric cambia (centripetal, in the form of an internal secondary ring of bundles, in Afromendoncia). ‘Included’ phloem absent. Vessel end-walls simple.
Reproductive type, pollination. Plants hermaphrodite.
Inflorescence, floral, fruit and seed morphology. Flowers (bi) bracteolate (the bracteoles large, spathaceous); very irregular; zygomorphic. The floral irregularity involving the androecium, or involving the perianth and involving the androecium. Flowers neither papilionaceous nor pseudo-papilionaceous; cyclic; tetracyclic. Free hypanthium absent. Hypogynous disk present; intrastaminal; annular (large, cupular).
Perianth with distinct calyx and corolla; theoretically 10; 2 whorled. Calyx reduced, theoretically 5 (?); 1 whorled; gamosepalous; shortly lobulate to blunt-lobed, or entire (then annular or truncate). Calyx lobes markedly shorter than the tube. Calyx open in bud (?); with the median member posterior. Corolla 5; 1 whorled; gamopetalous; contorted; more or less hypocrateriform (not inflated above); unequal but not bilabiate, or regular.
Androecium 4, or 5. Androecial members adnate (to the corolla tube); markedly unequal; free of one another; 1 whorled. Androecium exclusively of fertile stamens, or including staminodes. Staminodes when present, 1; in the same series as the fertile stamens; representing the posterior median member. Fertile stamens representing the posterior-lateral pair and the anterior-lateral pair. Stamens 4; didynamous; reduced in number relative to the adjacent perianth; oppositisepalous; alternating with the corolla members. Pollen shed as single grains. Pollen grains aperturate; 4–6 aperturate; colpate (the colpi very short).
Gynoecium 2 carpelled. Carpels reduced in number relative to the perianth. The pistil 1 celled, or 2 celled. Gynoecium syncarpous; synstylovarious to eu-syncarpous; superior. Ovary 1 locular (one locule more or less reduced or suppressed), or 2 locular. Gynoecium presumed median; stylate. Styles 1; apical. Stigmas 1, or 2 (the stigmatic lobes often more or less unequal). Placentation when unilocular, parietal; when bilocular, axile. Ovules in the single cavity 2; 2 per locule; funicled; collateral; non-arillate; presumed unitegmic; presumed tenuinucellate.
Fruit fleshy; indehiscent; a drupe (with a thick, bony endocarp); 1 seeded, or 2 seeded (1(–2) locular). Seeds non-endospermic. Embryo well differentiated. Cotyledons 2 (the cotyledons twice folded).
Physiology, biochemistry. Iridoids not detected. Saponins/sapogenins absent.
Peculiar feature. The funicles not as in Acanthaceae.
Geography, cytology. Paleotropical and Neotropical. Tropical. Central and tropical South America, tropical Africa, Madagascar.
Taxonomy. Subclass Dicotyledonae; Tenuinucelli. Dahlgren’s Superorder Lamiiflorae; Scrophulariales. Cronquist’s Subclass Asteridae; Scrophulariales. APG 3 core angiosperms; core eudicot; Superorder Asteranae; lamiid; Order Lamiales (as a synonym of Acanthaceae).
Species 60. Genera 2; Anomacanthus (Gilletiella), Mendoncia.
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: 25th November 2009. http://delta-intkey.com’.