Riccardia regnellii, an older name for R. amazonica (Marchantiophyta: Aneuraceae)

Riccardia amazonica is one of the most widespread tropical species in the genus Riccardia, occurring on soil, shaded rock and rotten wood in lowland and montane rainforests throughout tropical South America. A study of type specimens shows that the name R. amazonica should be replaced by R. regnellii. The latter species has been confused with R. sprucei. Riccardia regnellii is a further example of a Riccardia species that can be monoicous or dioicous. African specimens identified as R. amazonica do not belong to this species; the correct name for the African plants is R. longispica. Riccardia regnellii is lectotypified.