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:
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.
Tremella dichotomum Withering 1776
Tremella dichotomum Withering 1776
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