The aquatic plant genus Sagittaria contains about 35 species
and is distributed mostly in the New World but can also be found in
Europe and Asia. Sagittaria was analyzed phylogenetically using
sequences of the 5S nuclear ribosomal non-transcribed spacer (5S-NTS).
Taxa that have historically been placed in Sagittaria subgenus
Lophotocarpus, with the exception of members of the
Sagittaria subulata group, were strongly supported as
monophyletic and were placed basal to the remainder of the genus when
using the closely related genus Echinodorus (Alismataceae) for
outgroup comparison. Of the remaining taxa, sagittate leaved species
form a group that is sister to non-sagittate leaved species. The
sagittate leaved group has a disjunct distributional pattern between
the New World and Asia in which the Asian species appear to be the
basal members. The Sagittaria subulata group, within the
non-sagittate leaved species, is strongly supported as monophyletic.
Taxonomy, character evolution, biogeography of Sagittaria will
be discussed in light of these findings.
Key words: 5S-NTS, Lophotocarpus, monophyletic, Sagittaria, sagittate