9321767 Schilling Under the direction of faculty adviser Dr. Edward Schilling at the University of Tennessee, graduate student Robert Duff is employing molecular and morphological analyses to study the North American species of the primitive, spore-bearing plant Isoetes. The so-called quillworts (from the quill-like resemblance of their small leaves) grow in ponds, streams, or vernal pools, usually in small and highly restricted populations, scattered across the continent. Currently about 25 species are recognized in North America, and about 150 total in the world. The fossil record of quillworts shows the genus to be ancient; there is some evidence that it is one of the three surviving genera of the most primitive lineage of vascular land plants. New molecular data from chloroplast DNA restriction-enzyme mapping and from nucleotide sequencing of nuclear ribosomal DNA will be compared to traditional taxonomic information from morphology and chromosomes to develop a robust hypothesis of phylogenetic relationships of the North American species, and then to explore patterns of character evolution and geographical distribution. The generation of new molecular evidence from DNA analyses and the integration of that information with traditional morphological characters are revitalizing the taxonomic study of plants. Isoetes will be better understood as a result of this investigation.
