The Class Oomycetes, also known as water molds, is a group of fungi-like organisms that belong to the phylum Straminipila. Some common synonyms for this group include the Phycomycetes, Oomycota, and Oomyces. Water molds are characterized by their filamentous, branching structures and their ability to reproduce using both sexual and asexual methods. They are mostly found in aquatic environments, but can also be found in soil and on plant surfaces. Many water molds are significant plant pathogens, causing diseases such as downy mildew and Phytophthora root rot. Understanding the diversity and synonyms of this group is important for research and identification purposes.