MOODY, MICHAEL L.* and DONALD H. LES. Department of Ecology and Evolutionary Biology, University of Connecticut, Storrs, CT 06268. - Phylogenetic relationships in Haloragaceae emphasizing the aquatic genus Myriophyllum.
Phylogenetic analyses using parsimony and maximum likelihood methods
were conducted with data from the plastid genome (rbcL,
matK and trnK introns) to assess relationships among
Haloragaceae genera and among species in the aquatic genus
Myriophyllum. The Haloragaceae consist of 8 genera, three of
them aquatic (Proserpinaca, Laurembergia, and
Myriophyllum). Myriophyllum (55 species) is the largest
genus in the family and has its greatest species diversity centered in
Australia. Relationships among many aquatic plants have been
notoriously difficult to assess due to their convergent and highly
plastic vegetative morphology and reduced flower size. All of these
factors have made it difficult to determine species limits and
relationships among Myriophyllum or to assess its relationship
to other genera in the family. RbcL, matK and the
trnK introns have been very informative in delimiting
relationships among Haloragaceae genera and among species of
Myriophyllum. Results indicate an Australian origin for the
family with possible multiple origins of the aquatic habit. Results
also suggest a monophyletic Myriophyllum consisting of two well
supported clades. A clade of North American endemics (Schindler’s
Subgenus Tessaronia) is well supported and has its closest
sister taxa in Australia.
Key words: Haloragaceae, matK, maximum likelihood, Myriophyllum, parsimony, trnK introns