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River Jelly Lichen: A Glimpse into the World of Jelly Lichens

Dive into the fascinating world of River Jelly Lichens, unique organisms that blur the lines between algae and fungi. This article explores their identification, structure, distribution, and ecological significance.

Scientific Classification

• Scientific Name: Collema dichotomum (With.) Coppins &amp J.R. Laundon
• Common Name: River Jelly Lichen
• Family: Collemataceae
• Order: Lecanorales
• Synonyms: C. ohioense (for COLLEMA CONGLOMERATUM)

Distribution and Habitat

• This aquatic lichen thrives on submerged rocks and boulders in fast-flowing rivers.
• It is found in the upper reaches of rivers, including those in Northumberland and Wales.

Morphological Characteristics

• The thallus (lichen body) forms flattened or erect, bright to dark green rosettes.
• When wet, the thallus becomes gelatinous and black, with broadly rounded lobes.
• The lobes are convex, finger-like, and typically one to two centimeters long.
• Spores are 4-septate, hyaline, and measure 20-40 by 3-4.5.
• Some species like Collema nigrescens are leafy (foliose).

Ecological Role

• River Jelly Lichen is an important component of river ecosystems.
• Conservation efforts are in place to protect it, such as the River Jelly Lichen Action Plan in Wales.

Interactions with Other Organisms

• The photobiont (algal partner) is the cyanobacterium genus Nostoc.
• It can be affected by activities that impact salmonid populations.

Quirky Facts

• Collema dichotomum can resemble seaweed more than a typical lichen.
• Other Jelly lichens, like one with the English name "bat's wings," absorb water until jelly-like.

Further Information

• Encyclopedia of Life: Provides brief summaries and articles on Collema dichotomum.
• ARKive: Offers photos and facts about the River Jelly Lichen.