The oomycetes (Oomycota) are important organisms in the balance of diverse terrestrial and aquatic ecosystems, and take part in the cycling of nutrients. This study aimed to know the diversity of oomycetes in the Açude Joana Complex, in the municipality of Pedro II, Piauí state. In water and soil samples, 20 taxa, belonging to10 genera and five families, were identified from a total of 90 isolation. Among the species identified Achlya americana, Brevilegnia subclavata and Plectospira gemmifera are first record for Piauí. The taxa found are similar to other studies developed in the country.
geographic distribution; diversity; zoosporic organisms