Phylogenetic studies of the Spiridentaceae (Musci): Observations of three morphological characters associated with pleurocarpy

Abstract

CLADISTIC ANALYSIS OF RBCL SEQUENCE DATA SUGGEST THAT THE SPIRIDENTACEAE BELONG TO A DISTINCT PLEUROCARPOUS LINEAGE THAT IS PHYLOGENETICALLY INDEPENDENT OF OTHER PLEUROCARPUS MOSSES. AS THE RBCL DATA SUGGEST A NOVEL SET OF TAXA ALLIED WITH THE SPIRIDENTACEAE, IT IS IMPORTANT TO RE-EXAMINE THREE CHARACTERS THAT HAVE BEEN USED TO DIFFERENTIATE PLEUROCARPOUS LINEAGES. THESE CHARACTERS HAVE OFTEN BEEN MISLEADINGLY REGARDED AS PART OF THE DEFINITION OF PLEUROCARPY ITSELF, RATHER THAN CORRELATED CONDITIONS. ACCORDING TO THE PRESENT RESULTS, IN PLEUROCARPS RELATED TO THE SPIRIDENTACEAE, BRANCH PRIMODIA CAN NO LONGER BE TYPIFIED AS EXCLUSIVELY AXILLARY AND NAKED, AND PSEUDOPARAPHYLLIA ARE NOT ALWAYS ABSENT. THEREFORE, THESE CHARACTERS NO LONGER SERVE TO DISTINGUISH A PLEUROCARPOUS LINEAGE CONTAINING THE SPIRIDENTACEAE FROM OTHER PLEUROCARPOUS LINEAGES.