STEFANOVIC, SASA* and RICHARD G OLMSTEAD. University of Washington, 355325, Seattle, WA 98195, USA. - Molecular systematics of Convolvulaceae inferred from multiple chloroplast loci.
Convolvulaceae are a large family, traditionally comprising 55 genera
with some 1600-1700 species, the members of which present a rich
diversity of morphological characteristics and ecological habitats.
Previous efforts to systematize this diversity without a cladistic
phylogenetic framework have disagreed on the circumscription of the
family as well as tribal composition and relationship. In order to
circumscribe the family and assess the relationships among its major
lineages, a broad data set was constructed, containing representatives
of all ten recognized tribes of Convolvulaceae plus representatives of
putatively related families within Asteridae. This is done by using
four chloroplast regions: rbcL, atpB, psbE-J
operon, and trnL-F intron/spacer. The results indicate that
Convolvulaceae are sister to Solanaceae, with 100% bootstrap support
for each family and the clade comprising both families. Two of the
three groups that have been proposed previously as segregate families,
Cuscuta and Dichondreae, are nested within the Convolvulaceae in this
analysis, and the third, Humbertia, is the sister to all other
members of the family. The exact position of Cuscuta could not
be ascertained, but some alternatives were rejected with confidence.
The study identified several distinct monophyletic groups, some of
which correspond to earlier ideas. Close relationships of tribes
Hildebrandtieae with Cresseae and Ipomoeeae with Argyreieae (forming
Echinoconieae) were confirmed. The polyphyly of Poraneae and Erycibeae
is first reported in this study.
Key words: Convolvulaceae, cpDNA, Cuscuta, Humbertia