Sponsorship

This research was sponsored by the National Science Foundation (NSF) - Missouri Botanical Garden PEET project.

Systematic and Phylogenetic studies of the moss family Diphysciaceae (Buxbaumiidae).

(1) Dr Robert Magill (Director of Research, Missouri Botanical Garden, Adjunct Associate Professor and Research Associate Professor at the University of Missouri, St. Louis; and (2) Professor Elizabeth Kellogg, Biology Department, University of Missouri, St. Louis)

Diphysciaceae is a small family of mosses containing three genera, Diphyscium Mohr (19-21 species), Muscoflorschuetzia Crosby (1 species), and Theriotia Card. (2 species). Diphysciaceae consist of plants with short stems, well developed leaves, sessile capsules and pleated peristome structure (Figure 1). The Diphysciaceae are found on all major landmasses except Antarctica (Figure 2). The family is placed in the order Buxbaumiales together with the family Buxbaumiaceae which consists of one genus, Buxbaumia Hedw. (15 species). Monophylly of the Buxbaumiales was assumed based on the pleated peristome structure, not found in all other mosses. The Diphysciaceae show intermediate characteristics to major moss groups and, therefore, have pivotal position to our understanding of evolution of (i) those groups i.e. Andreaeales, Tetraphidales, Polytrichales, and the Bryales; and (ii) peristome structure which has been the basis of moss classification.

The study has the following objectives: (1) to predict phylogenetic relationships of Diphysciaceae to major moss groups, particularly Buxbaumiaceae, Andreaeales, Tetraphidales, Polytrichales and Bryales; (2) to determine phylogenetic relationships of genera and species within Diphysciaceae and circumscription of those taxa; (3) to study character evolution especially the peristome structure among major moss groups; and (4) to uncover biogeographic history of taxa in the Diphysciaceae.

Figure 1. Diphyscium foliosum (Photo by Prof. J. Snider)

Figure 2. Global distribution of Diphysciaceae

The research includes (1) a detailed study of character variation based on herbarium specimens and material collected during field surveys, (2) a wide range of taxon sampling for DNA analysis including taxa that have never been analyzed in previous studies, (3) use of morphological, developmental and molecular data sets for cladistic analyses to assess phylogenetic relationships, (4) use of the phylogenetic framework to study character evolution, and (5) assessment of the biogeographic history of the taxa based on taxonomic treatments, distribution data and phylogenetic analyses. Modern research techniques and research facilities at the Missouri Botanical Garden including the libraries, herbarium collections and TROPICOS database, and research facilities at University of Missouri St. Louis (Dr. Elizabeth Kellogg molecular laboratory) will be used.

Preliminary results of the taxonomic treatment led to the conclusion that only one genus, Diphyscium (15-20 species) should be recognized in the Diphysciaceae with the two genera, Theriotia and Muscoflorschuetzia reduced to synonymy. Phylogenetic analysis based on molecular data ( rbcL, and trnL) is underway and more molecular data is being gathered. Study of character variation for a complete taxonomic treatment is also continuing. Choose W³Most database page for taxonomic information and other details of taxa in Diphysciaceae.