Taxonomy

The river jelly lichen produces small rosettes up to 2.5cm in diameter. Thalli are greyish dark green to almost brownish when dry, and dark to bright green (sometimes with a brownish tinge). The dry lichen is very brittle but turns into a jelly like texture when wet.

Characters typical for the species are:

  • more or less dichotomous branching pattern
  • convex lobes with the disc-like reddish brown fruiting bodies (apothecia) on the upper surface of the thalllus

Other species of jelly lichens (Collema spp. and Leptogium spp.) in amphibious habitats are less submersion tolerant and they do not have the combination of characters of convex lobes and a dichotomous branching pattern.

Some liverworts may appear similar. In the field they can be easily distinguished by the absence of the reddish brown disk like fruiting bodies.

Basionym

Tremella dichotomum Withering 1776

Synonyms

  • Collema cataclysum Koerber 1855
  • Collema fluviatile (Huds.) Steudel 1824
  • Collemodium cataclystum (Koerb.) Nyl 1879
  • Enchylium fluviatile (Huds.)
  • Leptogium cataclystum (Koerber) Harm. 1905
  • Leptogium fluviatile (Huds.) Leighton
  • Leptogium rivulare auct. britt. non (Ach.) Montagne
  • Lichen fluviatilis Huds. 1778

Basionym

Tremella dichotomum Withering 1776

Synonyms

Collema cataclysum Koerber 1855

Collema fluviatile (Huds.) Steudel 1824

Collemodium cataclystum (Koerb.) Nyl 1879

Enchylium fluviatile (Huds.)

Leptogium cataclystum (Koerber) Harm. 1905

Leptogium fluviatile (Huds.) Leighton

Leptogium rivulare auct. britt. non (Ach.) Montagne

Lichen fluviatilis Huds. 1778