SafePlants

River Jelly Lichen: A Unique Aquatic Dweller

The River Jelly Lichen, a fascinating organism that often resembles seaweed more than a typical lichen, offers a unique glimpse into the world of symbiotic relationships. Often found in fast-flowing aquatic environments, this lichen presents a number of interesting characteristics.

Considerations for Pets

• The text mentions the lichen's gelatinous texture when wet, which might be appealing to some pets.
• It grows on submerged rocks, an environment that pets may access.

Considerations for Children

• The lichen's gelatinous texture when wet, which might be appealing to some children.
• It grows on submerged rocks, an environment that children may access.

Scientific Classification and Nomenclature

• Scientific Name: Collema dichotomum (With.) Coppins &amp Laundon
• Common Name: River Jelly Lichen
• Family: Collemataceae
• Order: Lecanorales
• Synonyms: While not explicitly stated, Collema ohioense is a synonym for COLLEMA CONGLOMERATUM, and the text generally discusses various Collema species.

Description and Morphology

• The thallus (lichen body) is foliose (leafy) and black, becoming gelatinous when wet.
• It typically grows to 2-4 cm broad, with broadly rounded lobes.
• Isidia and soredia are absent.
• Spores are 4-septate, hyaline, and measure 20-40 by 3-4.5 ?m.
• Other Collema species are described as having flattened or erect, bright to dark green rosettes with convex, finger-like lobes of about 1-2 cm long.

Distribution and Habitat

• The River Jelly Lichen is an aquatic lichen found on submerged rocks and boulders in fast-flowing rivers.
• It has been observed in the upper reaches of rivers in Northumberland.
• Populations of the River Jelly Lichen are thought to be the largest in Great Britain in some areas.

Ecology and Conservation

• The text references safeguarding existing populations of River Jelly Lichen by guarding against developments.
• It suggests that activities like outdoor river pursuits might compromise its conservation.

Interactions with Other Organisms

• The photobiont (the photosynthetic partner in the lichen symbiosis) is the cyanobacterium genus Nostoc.
• The text also mentions considering canoe access to rivers so as not to adversely affect salmonid populations and river jelly lichen.

Quirky Facts

• This lichen is described as looking more like seaweed than a lichen.
• The name "jelly lichen" comes from the fact that these lichens absorb water until they become jelly-like.

Further Information

• ARKive (implied, as a source of River Jelly Lichen photos and facts)
• Encyclopedia of Life