Saprolegnia multispora, a new oomycete isolated from water samples taken in a river in the Burgundian region of France.

Saprolegnia multispora is described from water and floating organic matter taken in the Tille River, in the Burgundian region of France. The new species is illustrated and compared with other species of the genus. Distinguishing characteristics of S. multispora are the production of smooth-walled oogonia containing many subcentric oospores which are (1-) 11-70 (-100) per oogonium. The antheridial branches supplying the oogonia are predominantly diclinous, but at times these may be monoclinous and androgynous. Morphological features of the oomycete and the sequence of the ITS region of its rDNA as well as their comparison with related species are discussed in this article.