Habit and leaf form. Creeping herbs (with a Lycopodium-like habit). With neither basal nor terminal aggregations of leaves. Stem growth conspicuously sympodial. Hydrophytic to helophytic; rooted. Leaves submerged to emergent. Leaves small; alternate; spiral (in high phyllotaxies); imbricate; sessile; non-sheathing; simple. Lamina dissected (but commonly apically bifid); linear (or filiform), or lanceolate; one-veined. Lamina margins entire.
General anatomy. Plants without silica bodies. Accumulated starch exclusively `pteridophyte type'.
Leaf anatomy. Stomata present; paracytic. Hairs absent (the plants glabrous save for ephemeral hairs in the leaf axils).
Lamina without secretory cavities (but with longitudinal air channels). The mesophyll not containing mucilage cells; without calcium oxalate crystals. Vessels present (?), or absent (with `vessel tracheids').
Stem anatomy. Secondary thickening absent (typically with three vascular bundles, and an aerenchymatous cortex separated from the narrow central cylinder by an endodermis). Xylem with vessels. Vessel end-walls scalariform, or reticulately perforated.
Root anatomy. Root xylem with vessels. Vessel end-walls reticulately perforated and scalariform.
Reproductive type, pollination. Hermaphrodite. Floral nectaries absent.
Inflorescence, floral, fruit and seed morphology. Flowers solitary; bracteate (the bracts membranous); small (aerial); regular; 3 merous; cyclic; tetracyclic. Perigone tube absent. Hypogynous disk absent.
Perianth with distinct calyx and corolla; 6; free; 2 whorled; isomerous; different in the two whorls. Calyx 3; 1 whorled; polysepalous; regular; imbricate, or valvate (`subvalvate'). Corolla 1; 1 whorled; polypetalous; imbricate; regular; pale pink to purple (rose), or white. Petals shortly clawed; entire.
Androecium 3. Androecial members free of the perianth; all equal; free of one another; 1 - whorled. Androecium exclusively of fertile stamens. Stamens 3; isomerous with the perianth; al\ter\ni\peri\anthial (representing the outer whorl); filantherous (the filaments slender, glabrous). Anthers basifixed; non-versatile; dehiscing via pores to dehiscing via short slits (apically); bilocular (occasionally), or four locular; tetrasporangiate; appendaged (sometimes). The anther appendages when present, apical (the dehiscence being sometimes at the end of a tubular appendage). Pollen shed as single grains. Pollen grains aperturate; 1 - aperturate; sulcate; finely reticulate; 2-celled.
Gynoecium 3 (the carpels alternating with the stamens); syncarpous; synstylovarious to eu-syncarpous; superior. Ovary 1 locular; sessile. Gynoecium stylate. Styles 1; attenuate from the ovary; apical. Stylar canal present. Stigmas 1, or 3; when single, 1 - lobed, or 3 - lobed (capitate to trifid). Placentation parietal. Ovules in the single cavity 25-100 (`many'); horizontal, or ascending; biseriate; orthotropous; bitegmic; thinly crassinucellate.
Fruit non-fleshy; dehiscent; a capsule. Capsules three valvular (dehiscing midway between the placentae, i.e. each valve with a median placenta). Seeds endospermic. Endosperm not oily (mealy, starchy and proteinaceous). Seeds with starch. Embryo small, discoid-unipapillate, forming an apical cap on the endosperm beneath the opercular `embryostega' at the micropylar end. Testa operculate (with a dorsal `embryostega', cf. Commelinaceae).
Physiology, biochemistry. Not cyanogenic. Proanthocyanidins absent. Flavonols present; quercetin. Ellagic acid absent.
Geography, cytology. Holarctic, Paleotropical, and Neotropical. Sub-tropical to tropical. Southeast U.S.A., Central and tropical South America, tropical Southwest Africa.
Taxonomy. Subclass Monocotyledonae. Superorder Commeliniflorae; Commelinales. Species 10. Genera 1; only genus, Mayaca.
Illustrations. mayac189.gif
Additional, to be intercalated. Flowers terminal (but simulating lateral by sympodial growth of the shoots).
