Parsimony analyses of morphology, restriction sites of the cpDNA, sequences from the nuclear, ribosomal internal transcribed spacer (ITS), and the chloroplast gene rbcL were performed to asses tribal and generic relationships in the subfamily Ixoroideae (Rubiaceae). The tribes Vanguerieae and Alberteae (Antirheoideae) are clearly part of Ixoroideae, as are some Cinchonoideae taxa. Pavetteae should exclude Ixora and allies, which should be recognized as the tribe Ixoreae. Heinsenia, representing Aulacocalyceae, is part of Gardenieae, as is Duperrea, a genus earlier placed in Pavetteae. Posoqueria and Bertiera and the taxa in the subtribe Diplosporinae should be excluded from Gardenieae. Bertiera and three Diplosporinae taxa are part of Coffeeae, while Cremaspora (Diplosporinae) is best housed in a tribe of its own, Cremasporeae. The mangrove genus Scyphiphora, recently placed in Diplosporinae, is closer to Ixoreae and tentatively included there. The combined analysis resulted in higher resolution compared to the separate analyses, exemplifying that combined analyses can remedy the incapability of one data set to resolve portions of a phylogeny. Twenty-four new rbcL sequences representing all five Ixoroideae tribes (sensu Robbrecht) are presented.

JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact support@jstor.org.. Missouri Botanical Garden Press is collaborating with JSTOR to digitize, preserve and extend access to Annals of the Missouri Botanical Garden.

Heterogeneous DNA substitution rates were found in the 18S-26S nuclear ribosomal DNA internal transcribed spacer (ITS) and external transcribed spacer (ETS) regions of Sidalcea (Malvaceae), a putatively young genus of annuals and perennials. The majority of comparisons revealed that the annual species had significantly higher molecular evolutionary rates than the perennials, whereas rates were consistently homogenous between obligate annual species. These findings led us to conclude that generation time or possibly another biological factor distinguishing annuals and perennials has influenced rates of molecular evolution in SIDALCEA: The congruence of relative-rate test results across both spacer regions reinforced the association between life history and rate of rDNA evolution across lineages of checker mallows. Evolutionary rate variation within perennials mainly involved three basally divergent lineages. The faster rate in one lineage, Sidalcea stipularis, compared with other perennials may be the result of genetic drift in the only known, small, population. The other two basally divergent lineages had slower evolutionary rates compared with the remaining perennials; possible explanations for these differences include rate-reducing effects of a suffrutescent (rather than herbaceous) habit and seed dormancy.

No abstract

No abstract

The morphologically homogenous tribe Vanguerieae was investigated phylogenetically using sequence data from the Internal Transcribed Spacer (ITS) region in the nuclear ribosomal DNA. Sequences from 41 Vanguerieae species representing 19 genera were produced, and a parsimony analysis was performed. The phylogenetic analysis has several clades with strong support, among which three new informal groups are discussed, i.e. the Vangueria group, the Fadogia-Rytigynia group and the Spiny group. Also found monophyletic with strong support are Multidentia, Keetia, Lagynias, and Pyrostria. Canthium and Rytigynia are revealed as polyphyletic; Vangueria, Tapiphyllum, and Fadogia are paraphyletic. Results from this ®rst phylogenetic analysis of the tribe clearly demonstrate a need for new circumscriptions of several genera. Morphological characters are discussed and putative synapomorphies are mentioned. Jackknife, bootstrap, and Bremer support are calculated and dierences found in support are discussed.

Warneckea consists of shrubs and small trees endemic to tropical forests in Africa, Madagascar, and Mauritius. Phylogenetic analyses of sequence data from the transcribed spacers of nuclear ribosomal DNA (ETS, ITS) indicate that W. sect. Carnosa Jacq.‐Fél. (1 sp., East Africa and Madagascar) is a divergent element that is best treated at subgeneric level. The analyses recovered three major lineages in W. subg. Warneckea, together forming a basal trichotomy. The three lineages represent W. sect. Strychnoidea (western and central Africa), sect. Warneckea (East Africa, Madagascar, Mauritius), and a third group with three West African species (W. fascicularis, W. guineensis, W. mangrovensis) comprising the newly proposed W. sect. Guineensea.

No abstract