Family Mendonciaceae

Mendonciaceae (Lindau) Bremek.

~ 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.