STEFANOVIC, SASA* AND RICHARD G. OLMSTEAD. Department of Botany, University of Washington, Box 355325, Seattle, WA 98195, USA. - Molecular systematics of Convolvulaceae inferred from cpDNA sequences.
Convolvulaceae are a large family, comprising approximately 50-60
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-trnF 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, phylogeny