NEINHUIS, CHRISTOPH1*, STEFAN WANKE1, KHIDIR W. HILU2, and THOMAS BORSCH1. 1Botanisches Institut und Botansicher Garten, Universitaet Bonn, Meckenheimer Allee 170, D-53115 Bonn, Germany; 2Department of Biology, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061. - Peppers and pipevines: phylogenetic relationships within Piperales.
In most broadscale studies Piperales are recognised as one of the best
supported clades within basal angiosperms. Although small in number of
genera, the group displays a surprisingly high morphological
diversity, so that a close phylogenetic relationship is not obviously
supported. Based on a dense sampling, representing all genera of
Saururaceae and Aristolochiaceae, Lactoridaceae as well as a selection
of Piperaceae, we present an analysis inferred from different coding
and non-coding regions of the chlorplast genome: the two spacers and
the intron of the trnT-trnF region, the matK gene and
adjacent regions of the trnK intron. The data show a sister
group relationship between Saururaceae and Piperaceae, which both
appear to be monophyletic. In previous studies the position of
Lactoridaceae and the subfamily Asaroideae of the Aristolochiaceae was
not clearly resolved. This ambiguity is considered to arise from long
branches leading to either Piperaceae as well as to Asaroideae, and
will be adressed in detail. Within Aristolochiaceae subfamily
Aristolochioideae, a fully resolved and well supported phylogeny could
be obtained. The genus Thottea branches first, followed by two
clearly monophyletic clades: One comprises the Asian/American species
that are often recognised as genus Isotrema, the other the rest
of the family comprising of Pararistolochia, a group of woody
lianas and geophytes of Central and South American species of
Aristolochia, the Mexican genus Einomeia as well as the
old world species of Aristolochia sensu stricto. Within
Saururaceae two clades are inferred, one consisting of Saururus
and Gymnotheca, the other of Houttuynia and
Anemposis.
Key words: Aristolochiaceae, matK, Piperaceae, Piperales, Saururaceae, TrnT-trnF