NEPOKROEFF, MOLLY1, WARREN L. WAGNER2*, ELIZABETH A. ZIMMER1, STEPHEN G. WELLER3, ANN K. SAKAI3, and RICHARD K. RABELER4. 1Laboratory of Molecular Systematics, Smithsonian Institution, Suitland, MD 20746, USA.; 2Department of Systematic Biology (Botany), Smithsonian Institution, Washington, D.C., USA.; 3Department of Ecology and Evolutionary Biology, University of California, Irvine, CA 92697, USA.; 4University of Michigan Herbarium, Ann Arbor, MI 48109, USA.. - Origin of the Hawaiian subfam. Alsinoideae and preliminary relationships in Caryophyllaceae inferred from matK and trnL C-F sequence data.
Relationships within the Caryophyllaceae have never been examined
explicitly using phylogenetic methods, despite the central position
and well-defined nature of the family in the order Caryophyllales
among the eudicots. Within Caryophyllaceae, the Hawaiian Alsinoideae
are an important model system for studying the insular adaptive shift
in breeding system from hermaphroditism to dimorphic breeding systems.
The relationships of the Hawaiian genera of subfam. Alsinoideae
Schiedea and Alsinidendron to the rest of the family and
relationships within the subfam. Alsinoideae are poorly known.
Previous studies suggested that the native Hawaiian Alsinoideae are
strongly supported as monophyletic and the result of a single
ancestral colonization to the archipelago. These studies suggested
that western North American members of the genus Minuartia are
sister to the Hawaiian clade, based on the shared presence of similar,
unique, nectary projections. Additionally, the monophyly and
relationships of the three main subfamilies, (Paronychoideae,
Caryophylloideae and Alsinoideae) are in question. The current
classification of the subfam. Alsinoideae has been based largely on
potentially highly labile characters, such as type of locule
dehiscence and number of styles relative to number of capsule teeth;
i.e. characters which may be homoplastic. A molecular phylogenetic
analysis using matK and trnL C-F sequences reveal that:
(1) the closest relatives of the Hawaiian Alsinoideae are a pair of
monotypic, circumboreal genera, Honckenya and
Wilhelmsia, (2) the subfamilies as currently delimited are not
natural groups; (3) the species-rich alsinoid genera Arenaria
and Minuartia are not natural groups and will likely require
nomenclatural reorganization to better reflect phylogenetic
relationships.
Key words: biogeography, Caryophyllaceae, Hawaiian islands, Honckenya, Schiedea, Wilhelmsia