Independent Origins of Cleistocarpy in the Splachnaceae: Analyses of cpDNA Sequences and Polyphyly of the Voitioideae (Bryophyta)

Abstract

Many dung mosses (Splachnaceae) are characterized by insect-mediated spore dispersal. All of the ento- mophilous 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. The phylogenetic significance of sporophytic characters within the family Splachnaceae is briefly discussed. Some members of the moss family Splachnaceae are unique among seedless land plants: they display fea- tures considered linked with insect-mediated spore dispersal. Such putative adaptations include an en- larged, brightly colored hypophysis, emission of vola- tile compounds that attract insects, sticky spores, and a pseudocolumella (Koponen 1990; Demidova and Fi- lin 1994). The systematics of the family is based pri- marily sporophytic features, and in particular of com- binations of entomophily related characters and the ar- chitecture of the peristome (Koponen 1982). The