Riella helicophylla (Mont.) Hook., a new addition to the macrophytic wetland flora of the Maltese Islands (Bryophyta, Marchantiopsida, Riellaceae)

Abstract

The freshwater liverwort Rie/ia helicophylla (Mont.) Book. is recorded for the first time from the Maltese Islands. A number of individuals were cultured following hydration of desiccated sediment collected from Ghadira s-Safra, a saline marshland situated on the north-eastern coast of Malta. Subsequent fieldwork has not revealed any field occurrences of the species in the Maltese Islands, indicating that this record may be due to a chance occurrence of viable spores in the sediment, possibly as a consequence of transport by means of migrating waterfowl. The apparent absence of the species in the wild may also be~ due to habitat degradation and to a sub-optimal physico-chemical environment.