Species At Risk

Flooded Jellyskin

(Leptogium rivulare)
Provincial Status: Threatened
Flooded Jellyskin
Flooded Jellyskin occurrences map


Flooded Jellyskin is a leaf-like lichen with bluish-grey lobes, a smooth, unwrinkled surface, with numerous small brown discs which are the fruiting bodies. When Flooded Jellyskin gets wet, the lobes become gelatinous and translucent, resulting in the name “jellyskin.” Lichens grow slowly – perhaps only one to two millimetres per year. Flooded Jellyskin individuals can grow to about six centimetres, but are more often found in clusters that can form large aggregations on tree bases, and sometimes rocks, up to half a metre wide.


Flooded Jellyskin is found in eastern North America, Western Europe and Tanzania. In Canada, there are seven published populations (of which two are historic) of Flooded Jellyskin in Ontario and one in Manitoba. However, recent surveys for Flooded Jellyskin by the Ministry of Natural Resources have identified additional populations in Ontario, which are being reviewed by the Natural Heritage Information Centre.


Flooded Jellyskin is mainly found growing on the bark at the base of trees that are periodically flooded, typically during the spring. The trees are species that can withstand substantial flooding such as: Black Ash, Red Maple, American Elm and more rarely, Balsam Poplar. It can also be found growing on rocks that are subject to similar periodic flooding.


Threats to Flooded Jellyskin include habitat loss and degradation due to a combination of recreational uses and development. Other potential threats include water quality impacts such as sediments coating the host tree trunks and reduced water quality from contaminants. Invasive species pose a threat to Flooded Jellyskin including Emerald Ash Borer, which kills the host trees upon which the lichen depends, and non-native slug species, which are predators of Flooded Jellyskin. Climate change and associated declines in flood levels are also considered a threat.


Flooded Jellyskin receives protection under Ontario’s Endangered Species Act and the federal Species at Risk Act.

For more information on legislation that helps protect Ontario's species at risk visit ontario.ca/speciesatrisk.

What You Can Do to Help the Flooded Jellyskin

  • The Ministry of Natural Resources tracks species at risk such as the Flooded Jellyskin. You can use a handy online form to report your sightings to the Natural Heritage Information Centre. Photographs with specific locations or mapping coordinates are always helpful. nhic.mnr.gov.on.ca
  • Contact local naturalist groups such as the Ontario Vernal Pool Association (www.ontariovernalpools.org) to find out how you can help improve habitat for Flooded Jellyskin
  • Report any illegal activity related to plants and wildlife to 1-877-TIPS-MNR (847-7667).
  • Private land owners have a very important role to play in species at risk recovery. If you find Flooded Jellyskin on your property, you may be eligible for stewardship programs that support the protection and recovery of species at risk and their habitats. For more information, visit: ontario.ca/speciesatrisk.
  • Invasive species seriously threaten many of Ontario’s species at risk. To learn what you can do to help reduce the threat of invasive species, visit: ontario.ca/invasivespecies ; www.invadingspecies.com ; www.ontarioinvasiveplants.ca ; and, www.invasivespecies.gc.ca .

Did you know?

Flooded Jellyskin is considered rare wherever it occurs worldwide.

Did you know?

Although there appears to be ample suitable habitat in Canada, the rarity of Flooded Jellyskin is believed to be due to limitations in how it spreads. Because it spreads through water, it’s possible that a combination of dams and siltation in many waterways in North America and Europe limits movement of the lichen’s spores to short distances.

Did you know?

There are over 1000 lichen species know to occur in Ontario.

The Endangered Species Act

Contact your local ministry office

Often the best source of local information on species at risk is your nearest ministry office. Call with your questions or concerns.