What do we know about hybridization among bryophytes in nature?

Abstract

Despite being recognized as a widespread and evolutionary important phenomenon among vascular plants, interspecific hybridization among bryophytes has been strongly underestimated. In the present review, we summarize knowledge about bryophyte hybrids that are found in nature. Mechanisms of reproductive isolation in bryophytes are compared with those in vascular plants. The morphological and genetic features of sporophytic hybrids and their gametophytic progeny are discussed, as well as some inferences about hybrid fitness. The data available indicate that spontaneous hybridization among bryophytes is not uncommon and has an important, though still not completely understood, evolutionary significance. The existence of many allopolyploid taxa supports this conclusion. Finally we suggest some methods for further investigation of hybridization among bryophytes in nature.Key words: hybridization, bryophytes, isolating mechanisms, evolution, hybrid fitness, hybrid features.