A phytochemical and morphological study of the liverwort Plagiochila retrorsa Gottsche, new to Europe

The Neotropical liverwort Plagiochila retrorsa Gottsche is conspecific with P. sharpii H.L.Blomq., known previously as a Southern Appalachian endemic, as well as P. tricarinata Carl and P. permista Spruce var, subintegerrima Herzog from Costa Rica. It has been discovered recently in the Azores and M adeira, new to Europe. Illustrations, SEM micrographs of spores and elaters , nuclear magnetic resonance (NMR) fingerprints and gas chromatography-mass spectrometry (GC-MS) data are presented, based on American and European ma terial. Costa Rican material used for an earlier phytochemical study has no w also been identified as P. retrorsa. Although NMR fingerprinting initiate d the present discoveries, the NMR fingerprint of P. retrorsa is not unique and NMR fingerprinting alone is not sufficient to identify the species. P. retrorsa belongs to the 9,10-dihydrophenanthrene chemotype group and the t wo principal secondary metabolites are 3,5-dimethoxy-9,10-dihydrophenanthre n-2-ol and methyl 4-hydroxy-4'-O-methyllunularate.