Lourteig. A. 1951. Mayacaceae. Not. Syst. 14: 234-248.

 

 

One genus and 4 spp., 3 centered in New World Tropics, from southeastern U.S.A. and Mexico to Argentina and Uruguay, 1 in tropical southwestern Africa; 2 spp. reported for CR.

Aquatic moss-like herbs. Perennial, or sometimes annual, submersed in shallow water or amphibious, becoming exposed/semi-terrestrial at edges of aquatic habitats. Stems simple or branched, elongate when submersed, usually reaching near the water surface, or short and creeping, with densely compacted branching, procumbent to somewhat erect when stranded, then appearing moss-like. Leaves spirally arranged, linear to filiform, slightly widening toward base, apex bifid or acute, sometimes bristle-tipped. Flowers solitary or few-flowered in leaf axils, bisexual, actinomorphic, typically emergent in submersed habitats. Sepals 3, narrowly lanceolate, acute. Petals 3, broadly obovate to nearly round, white or pink to violet. Stamens 3, opening by apical pores borne on a short or elongate tube, or by pore-like apical slits. Ovary superior, 1-locular; style slender, stigmas 3. Fruit a capsule, dehiscing by 3 valves; seeds small, dark.

This aquatic moss-like group is poorly collected and can likely be mistaken for bryophytes when vegetative.

1. Flowers whitish; anthers dehiscent by an apical slit (sometimes appearing pore-like, lacking an apical tube; filaments equal or longer than the anthers ................. M. fluviatilis

1. Flowers pinkish to nearly violet (rarely white); anthers with conspicuous apical extension, dehiscent by an oblique pore at the tip; filaments shorter than the anthers........................... ............................................................................................................................M. sellowiana

Mayaca fluviatilis Aublet, Hist. Pl. Guiane 42, pl. 15. 1775. [M. Aubletii Michx.]

Leaves linear to filiforms, apex bifid or acute or both, acute tips more prevailent. Flowers whitish. Stamens with anthers dehiscent by an apical slit, filaments slender, equal or longer than the anthers.

Submersed, amphibious, or semi-terrestial in wet soil. Lake margins, ponds, pools, or ditches. Lowlands; Llanura Guatusos, Guanacaste lowlands [Crow 7601, CR, F, MO, NHA], Aug., Nov.; probably occurring widely at lower elevations. Southeastern U.S.A. to Bolivia, northern Argentina and Paraguay.

Morphologically very variable depending on fluctuation of water levels throughout the wet season. Although the other species of Mayaca have leaves that are typically bifid, this character is not consistent--M. fluviatilis tends to be more typically acute, with some bifid leaves. The leaves tend to be longer, nearly filiform, typically ca. 5-7 mm.

Mayaca sellowiana Kunth, Enum. Pl. 4: 32. 1843.

Leaves linear to filiform, apex typically bifid. Flowers pinkish to nearly violet, rarely white. Stamens with anthers dehiscent by an oblique apical pore at distal end of a conspicuous apical extension; filaments broad, typically shorter than the anthers.

Submersed, amphibious, or semi-terrestial in wet soil at margin of lakes, ponds, pools, or ditches. Lowlands to moderate elevations, Valle General, Cordillera Tilaran [Crow 6941, CR, MO, NHA], Jan., Aug.; probably occurring widely at lower elevations. Venezuela and Colombia, to Brazil, Bolivia, Paraguay, Uruguay, and Argentina.