PHYLOGENY OF THE CHARACEAE (CHAROPHYTA) INFERRED FROM ORGANISMAL AND MOLECULAR CHARACTERS

Phylogenetic hypotheses proposed for extant genera of the Characeae by WOOD & IMAHORI (1965) and by KHAN & SARMA (1984) are based on morphol ogical characters, and morphological characters and chromosome numbers respectively. For all six extant taxa, cladistic analyses have been p erformed on organismal characters and chromosome numbers, sequence dat a from the nucelar-encoded small subunit rRNA gene, and a combined mor phological and molecular data set. These analyses support: 1) monophyl y of the Characeae, 2) monophyly of tribe Chareae, 3) placement of Nit ellopsis basal to the rest of the Chareae, and 4) monophyly of Lamprot hamnium. Neither the WOOD & IMAHORI nor the KHAN & SARMA hypothesis is strongly supported. Additional analyses based on a more comprehensive taxon sampling may help resolve: 1) monophyly of Chara, 2) monophyly of Nitella, 3) monophyly of the Nitelleae, 4) placement of Nitella axi llaris, and 5) placement of Lamprothamnium.