Salvinia molesta is rarely found growing in the canals of Collier County. It is native to Brazil but escaped cultivation (Wunderlin, 2003). It grows year round.
Free floating fern; stems rootless, hairy, about 10 cm long.
Borne in threes; appear 2-ranked, but with 3rd leaf finely dissected and dangling, resembling roots; rounded to somewhat broadly elliptical, to 2 cm long, with cordate base, upper surface with 4-pronged hairs joined at the tips (resembling an egg beater), lower surface hairy.
In a nutlike sporocarp (a multicellular structure), trailing beneath.
Spreads rapidly and prolifically into a monoculture which can shade out underwater natives, leaving large bare bottom areas.
1. Invasive and Non-native Plants You Should Know - Recognition Cards, by A. Richard and V. Ramey. University of Florida-IFAS Publication # SP 431. 2007.