Photo by Melody

Definition of water mold

Categorized under "General"

Definition as written by paulgrow:

The common name for a group of organisms that superficially resemble fungi but are are placed in the kingdom Protista. There are two important phyla of water molds: chytrids and oomycetes.


The chytrids live in salt- and freshwater and in moist soil. They obtain their metabolic energy from decaying plant and animal material; or by attacking plants, fungi, and algae.

They typically take the form of small masses - called sporangia - from which many hairlike rhizoids protrude and absorb nutrients. Reproduction can be by simple division or by more complicated processes. There are approximately 900 species of chytrids.

The oomycetes resemble fungi, but differ from fungi in that cellulose is present in their cell walls. The hyphae of oomycetes have specialized regions that can produce distinct male and female gametes. Oomycetes can also reproduce asexually.

Many oomycetes are aquatic and many others live in water in certain stages of the life cycle. Most of the 800 species of oomycetes are saprobes but those that are parasitic are of great significance: they cause downy mildew - a disease often affecting grapes; late blight of potatoes, an outbreak of which led to the 19th century potato famine in Ireland; and blue mold of tobacco.

Other parasitic water molds cause diseases of fish and fish eggs.


Add a definition to this term

Return to the Gardenology homepage

Return to Dave's Garden


Overwhelmed? There's a lot to see here. Try starting at our homepage.

[ Home | About | Advertise | Media Kit | Contact Us | Do Not Sell My Personal Information]

Back to the top