Independent origins of cleistocarpy in the splachnaceae: Analyses of cpDNA sequences and polyphyly of the Voitioideae (Bryophyta)
Many dung mosses (Splachnaceae) are characterized by insect-mediated spore dispersal. All of the entomophilous species are coprophilous, whereas anemophilous species are humicolous or epiphytic. The three species of the Voitioideae are coprophilous but are distinguished from other members of the family by sporangia that remain closed (cleistocarpous) and lack a peristome. Spores are released when the sporangial wall disintegrates. Phylogenetic analyses of nucleotide sequences of the trnL-trnF region and the rps4 locus (cpDNA) for 25 species of Splachnaceae suggest that this combination of characters arose twice within the Splachnaceae and that Voitia grandis is more closely related to species of Tayloria subgenus Tayloria rather to the other species of Voitia, which are nested within the genus Tetraplodon. Hence the new combination Tayloria grandis (Long) Goffinet & Shaw is made. Although the optimal trees were left unrooted, our results resolve the Voitioideae (i.e., the genus Voitia) as nested within the Splachnoideae. Tile phylogenetic significance of sporophytic characters within the family Splachnaceae is briefly discussed.