Introduction

Salvinia molesta D. S. Mitchell (Salviniaceae) (salvinia) is a floating water fern of tropical and subtropical distribution worldwide. Its center of origin is southeastern Brazil. It is an extremely important invasive species and its biological control is an extraordinary, contemporary, success story.

Salvinia molesta is named after Antonio Maria Salvini (1633-1729), University of Florence. The specific epithet molesta originates from the Latin molestus meaning ‘troublesome,’ ‘annoying,’ referring to its weediness (Parsons and Cuthbertson, 2001).

Taxonomy

Salviniaceae in Hydropteridales comprises the monotypic taxon Salvinia with 10-12 species (Hassler and Swale, 2002): S. minima Baker, S. oblongifolia Martius, and four species in the S. auriculata complex originating in the tropical Americas. The S. auriculata complex comprises species in which the upper section of each leaf hair forms an ‘egg-beater’ or ‘cage’ shape by splitting apart below the tip and joining at the tip (Fig. 19.1) (Forno, 1983) and includes S. auriculata Aublet, S. biloba Raddi, S. herzogii de la Sota, and Salvinia molesta D. S. Mitchell. Salvinia molesta was separated from S. auriculata by Mitchell (1972). Most literature that refers to S. auriculata as a pest species outside South America and Trinidad actually refers to S. molesta.

Herzog (1935) recognized S. auriculata Aublet, and this name was applied to the invasive species that occurred outside South America. De la Sota (1962) recognized that S. auriculata comprised a number of species and described S. herzogii.