Status of an ongoing systematic study of Plagiothecium.
Justin Thomas Wynns
dept. Agriculture and Ecology, Copenhagen University
Plagiothecium is a conspicuous and widely distributed genus of pleurocarpous mosses, typically growing on soil or humus in forests, heaths and swamps. The genus is well characterized morphologically by plants that are mostly medium-sized to large, flattened, and highly glossy, with decurrent leaves. Many species produce characteristic small uniseriate gemmae in abundance.
Plagiothecium appears to be a mostly natural genus that includes several species-complexes and some anomalous species. A large number of taxa have been described, and some are very poorly known. Although several excellent regional treatments of the genus exist, Plagiothecium has not been monographed on a worldwide scale. The goal of my study is to obtain a molecular phylogeny of Plagiothecium that will serve as the systematic basis for a projected worldwide monograph.
Pleurocarpous mosses have undergone rapid morphological diversification in recent evolutionary history, and DNA sequence data can be very uniform in this group. To identify the most useful genetic loci for evolutionary reconstruction in Plagiothecium, I have sequenced a number of different loci (mostly chloroplast, some nuclear) for a small number of taxa. In this Ph.D. Status Seminar, I discuss the results of this ongoing initial phase of my study, including the taxonomic conclusions that are emerging.
