Radula

Radula is a genus of liverwort in the family Radulaceae. The genus includes 248 species of small plants that typically grow as green, scaly patches on tree trunks, logs, or rocks in moist environments. It is distinguished from other liverworts by several unique features, including the production of root-like structures (rhizoids) exclusively from leaf surfaces and characteristic branching patterns. The plants have rounded, overlapping leaves consisting of two unequal lobes, with considerable variation in structure across species. Following a major taxonomic revision in 2022, the genus comprises five subgenera with distributions ranging from tropical to temperate regions. The oldest known fossil species, R. cretacea, found in Burmese amber, dates to the Cenomanian age, though molecular evidence suggests the genus originated in the Triassic period, around 228 million years ago.