Amber Jelly Roll, known by the Latin name Exidia crenata is a brownish jelly fungus that grows on dead hardwood and can be found through out temperate North America in moist environments or after a rain. Exidia crenata is a species of fungus in the family Auriculariaceae. Click on the hyperlink to learn more about Auriculariaceae

This species is saprobic, meaning that it grows on recently fallen wood, decomposing the wood in the process. This particular species can be found on dead hardwood, especially Oaks.

The fruiting bodies grow separately but will generally bunch together giving the appearance of one solid mass. The individual bodies are .25 to 1.5 inches wide and are gelatinous in nature. They will dry out in times of drought but can reconstitute them selves after a strong rain.

The species was first described in Nort America in 1822 by Lewis David de Schweinitz an American-German mycologist. Schweinitz classified in the genus Tremella but in the same year was transferred to the genus Exidia.

Until molecular testing was completed, Exidia crenata was considered a synonym to the European Exidia recisa. Based on cladistic analysis of DNA sequences it has been suggested that E. recisa (European variety) and E. crenata (North American) are different species. It seems that all descriptions for the two species are identical and I have not found anything to suggest a visible difference in the two species. See the pdf below.

Sources:

https://www.mushroomexpert.com/exidia_recisa.html

https://www.mushroom-appreciation.com/amber-jelly-roll-fungus.html