Systematics Section / ASPT
Moody, Michael L. , Les, Donald H. .
Getting wet in a sunburnt country: Phylogenetics of Haloragaceae R. br. inferred from nuclear and chloroplast DNA sequences.
Haloragaceae are a relatively small family of 8 genera and approximately 120 species; yet, they display a rare and extreme diversity in habit, ranging from small trees to submerged aquatics. The center of diversity for the family is Australia where three genera are endemic. Four genera are primarily terrestrial (Haloragodendron, Glischrocaryon, Haloragis, and Gonocarpus) while four are aquatic/semiaquatic (Meziella, Proserpinaca, Laurembergia, and Myriophyllum). Evolutionary relationships within Haloragaceae have been difficult to ascertain, particularly due to uncertain placement of the various aquatic/semiaquatic genera in relation to each other and the terrestrial taxa. Phylogenetic analyses using both chloroplast (trnK, matk) and nuclear (ITS-1, ITS-2 and 5.8S) sequences have given insight into relationships among all the genera and many species of Haloragaceae. The terrestrial woody genera (Glischrocaryon and Haloragodendron) are basal in the family while the number of aquatic habit origins is equivocal. The position of the recently rediscovered monotypic genus Meziella is supported as sister to Myriophyllum. The semiaquatic species Haloragis brownii is phylogenetically distant from other Haloragis and has unique morphological characters (e.g. bipinnate leaves, bicarpellate gynoecium) that argue for its distinct generic status. The large aquatic genus Myriophyllum is divided into two distinct clades. Generic and subgeneric limits are similar to those proposed in Orchard's treatments, but there are some striking differences involving the generic limits within the Haloragis/Gonocarpus clade and alliances within Myriophyllum (e.g., M. veriticillatum alliance and M. aquaticum alliance).
1 - University of Connecticut, Ecology & Evolutionary Biology, 75 North Eagleville Rd., Storrs, Connecticut, 06269-3043, USA
Presentation Type: Paper
Location: Cottonwood A (Snowbird Center)
Date: Monday, August 2nd, 2004
Time: 9:15 AM