ISSN:
1615-6110
Keywords:
Brexioideae
;
Brexia
;
Ixerba
;
Roussea
;
Saxifragaceae s. l.
;
18S rDNA andrbcL sequence analysis
;
molecular systematics
;
phylogenetic analysis
;
taxonomy
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract Previous molecular phylogenetic analyses have demonstrated that Saxifragaceae sensu lato are polyphyletic, with component lineages scattered throughout the eudicots. As part of our effort to elucidate the relationships of members of Engler and Prantl's Saxifragaceae s. l., we undertook a molecular systematic study of subfamily Brexioideae, which comprises three genera:Brexia, Ixerba, andRoussea. Not all taxonomic treatments have concurred, however, in placing these genera together. To elucidate relationships among these three genera as well as their relationships to other angiosperms we constructed large data sets ofrbcL, 18S rDNA, andrbcL + 18S rDNA sequences. Our phylogenetic analyses indicate clearly that Brexioideae are polyphyletic.Brexia is part of a celastroid clade that also includesParnassia, Lepuropetalon, and Celastraceae.Ixerba appears as sister to a large eurosid I clade;Roussea appears as part of Asterales. Molecular data, therefore, indicate that Brexioideae are a polyphyletic assemblage and component genera should ultimately be incorporated into other groups. Our studies continue to demonstrate the polyphyly not only Saxifragaceae s. l., but also of its constituent subfamilies.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00985579
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