SMITH, ALAN R.*, HARALD SCHNEIDER, BARBARA S. PARRIS, CHRISTOPHER H. HAUFLER, TOM A. RANKER, JAMES P. THERRIEN, AND JENNIFER M. O. GEIGER. University Herbarium, University of California, Berkeley, CA 94720; Fern Research Foundation, 21 James Kemp Place, Kerikeri, Bay of Islands, New Zealand; Department of Ecology and Evolutionary BiologyUniversity of Kansas, Lawrence, KS 66045; University Museum Herbarium, University of Colorado, Boulder, CO 80309. - Phylogeny of Grammitidaceae and Polypodiaceae inferred from two large data sets: rbcL and morphology.
Recent studies utilizing nucleotide sequence data have indicated that
Grammitidaceae and Polypodiaceae form a monophylum, in which the
monophyletic Grammitidaceae are nested in a paraphyletic
Polypodiaceae. This hypothesis is tested with an enlarged rbcL data
set and a new morphological data set. Nearly all proposed genera of
Grammitidaceae and Polypodiaceae are included with one or more
representatives in both data sets. The two data sets utilize the same
taxa and are analyzed both separately and combined. Our analyses
reveal monophyletic groups within both families (and the relationships
among Grammitidaceae and Polypodiaceae). Several disputed genera in
both families are shown to be polyphyletic or paraphyletic, e.g.
Grammitis, Microgramma, Microsorum, and
Polypodium, but many monophyletic units correspond with
previously proposed genera, e.g. Campyloneurum, Pecluma,
and Prosaptia. Several large clades have biogeographical
continuity, being restricted to either the Paleotropics or Neotropics.
The entire group probably had an Old World origin, whereas
Grammitidaceae are sister to New World Polypodiaceae. However a
number of genera have attained pantropical distribution, presumably in
their relatively short history. Important changes in the
classification are outlined. The phylogenetic results are compared
with traditional taxonomic units based on morphological characters,
and conflicts are discussed. Both families are primarily
tropical/subtropical epiphytes, and some morphological characters may
reflect adaptation to similar habitats. Such similarities cause
conflicts in the recognition of natural groups with traditional and
phylogenetic methods. The rbcL data set is used to recognize
convergent characters and evolutionary trends in epiphytic plants.
Key words: biogeography, epiphytes, ferns, Grammitidaceae, phylogeny, Polypodiaceae