Abstract
Odontoschisma prostratum (Sw.) Trevis. and Jungermannia callithrix Lindenb. et Gottsche, two liverworts mainly distributed in the Neotropics, are reported at hand of many collections from Macaronesia. O. prostratum occurs on 8 of the 9 Azorean islands, growing on all type of substrates, even epiphyllous, but rarely in bogs. J. callithrix is known from 8 Azorean islands and from Madeira, growing epigeic. The phytogeographical interest of the occurrence on the Azores of some 39 liverworts (among 147) belonging to the neotropical and/or paleotropical elements is discussed. Most of the neotropical species may have been easily transported to the Azores by the frequent depressions (or occasionally storms) moving rapidly at relatively low altitude (3,000 m) from the North or Central American eastern coasts or from the Caribbean islands and Bermuda to Western Europe in a few days. Only a few of these species could have been be introduced by human activities, mainly along the coast.