The Rhizogoniaceae is a predominantly southern hemisphere family of eubryalean mosses with a centre of diversity in Australasia and a distribution pattern suggestive of a late mesozoic Gondwanic origin. Many of the taxa are unusual with respect to characters associated with the distinction between acrocarpy and pleurocarpy, having been variously considered acrocarps or pleurocarps due to the occurrence of lateral perichaetial modules basally or distally on upright, tufted, determinate shoots. Such observations are consistent with recent cladistic analyses suggesting that at least some members of the family may be critical to the understanding of the evolution of pleurocarpy. As a prelude to a planned combined morphological and molecular phylogenetic study of the group, a preliminary examination of morphological characters was undertaken within the context of recent clarifications and redefinitions of pleurocarpy and acrocarpy. Initial observations confirm that the family contains both unambiguously acrocarpous and unambiguously pleurocarpous taxa according to currently accepted definitions and further suggest that the forms of pleurocarpy found within the Rhizogoniaceae are associated with sets of character states that are different from those associated with the "true pleurocarps".

Key words: acrocarpy, morphology, phylogeny, pleurocarpy, Rhizogoniaceae