AbstractMinute ovoid monolete spores and thick - walled pseudoelaters are the main characters for consideringAnthoceros dussiiSteph. the type species of the new genusLeiosporocerosHässel and the new family Leiosporocerotaceae Hässel of the Anthocerotopsida.Anthoceros rigidusLehm. ex Gott.,Anthoceros leiosporusGott.,Aspiromitus dussii(Steph.) Steph.,Aspiromitus leiosporusGott. ex Steph., andPhaeoceros(Aspiromitus)dussii(Steph.) S. Arnell, are synonyms. Latin and English descriptions are given, SEM micrographs of spores and pseudoelaters. The genus thrives in the Antilles.