English: Watermoss.
Clades:
Salviniales;
Salviniidae;
Lycopodianae;
Pteridophyta;
Plants.
Members: 1 genus, Salvinia; 14 species.
Region: North America, Mexico, West Indies, Central America, South America, Eurasia, Africa,
Madagascar, South Borneo, Asia.
Habitat: aquatic; mostly tropical.
Ecology: invasive weed in warm climates, South America; forming dense mats over still waters.
Use: mopping up oil spills; trichomes as a model for a similarly hydrophobic synthetic polycarbonate.
BotanyFern; floating; small.
Root: rhizophorous.
Stem: creeping; branched; non-protostelic; bearing hairs on the leaf surface papillae; trimerous whorls, 2 green, sessile or short-petioled, flat, entire, floating, 1 finely dissected, petiolate, rootlike and pendent; submerged leaves bearing sori that are surrounded by basifixed membranous indusia (sporocarps).
Leaves: ligulate; floating; upper side appears to face the stem axis, is morphologically abaxial.
Sporocarps: two types; either megasporangia that are few in number (approximately 10), each with single megaspore, or many microsporangia, each with 64 microspores.
Spores: globose, trilete; heterosporous, two kinds and sizes; megagametophytes and microgametophytes protruding through sporangium wall; megagametophytes floating on water surface with archegonia directed downward; microgametophytes remaining fixed to sporangium wall.
The small, hairlike growths, known as trichomes or microgametical follicles, are not known to have any productive function, and are currently a biological mystery.
Stages Remedies1
Salvinia auriculata