A Revision of the \u27Cryptandra propinqua\u27 Complex (Rhamnaceae: Pomaderreae)

Volume: 128Start Page: 81End Page: 9

Phylogeny and classification of Eucalyptus subgenus 'Eudesmia' (Myrtaceae) based on nuclear ribosomal DNA, chloroplast DNA and morphology

Phylogenetic analysis of Eucalyptus subgenus 'Eudesmia' is presented on the basis of the following three datasets: sequences of the internal transcribed spacer (ITS) and the external transcribed spacer (ETS) regions from nuclear rDNA, sequences of the psbA–trnHintergenic spacer region from chloroplastDNA,and morphological characters, including stamen bundling, operculum development, seeds and trichomes. Studies of floral development were essential for understanding the morphology of mature flowers and interpretation of synapomorphy and homoplasy. A summary phylogeny was constructed from a maximum parsimony analysis of those nodes coded as characters that had support in the molecular trees together with morphological characters. A revised infra-subgeneric classification is presented on the basis of the summary phylogeny, and compared with classifications of Hill and Johnson (1998) and Brooker (2000). Differences relate to relationships between clades and taxonomic rank (sections, series and subseries) and valid names of Brooker (2000) are conserved where possible. One main clade of 14 species (section Limbatae), many of mallee growth form, was found in all analyses; this clade is distributed in the South-West of Western Australia and adjacent Interzone and desert areas. A second main clade (section Complanatae) occurs in the northern and eastern tropical and subtropical regions of Australia, including Kimberley, Arnhem, Queensland and NewSouth Wales. This section includes 'E. tetrodonta', previously treated as an isolated taxon in a monotypic section; however, this species is related to 'E. baileyana', 'E. similis', 'E. lirata' and series 'Miniatae'. The hypothesised phylogeny provides a framework for further analyses of biogeography and ecology, including functional traits

A box on the river: The phylogenetics and phylogeography of Eucalyptus baueriana (Eucalyptus sect. Adnataria ser. Heterophloiae).

We present a phylogeographic study of the tree species Eucalyptus baueriana Schauer, which occurs in disjunct areas on the near coastal plains and ranges of the south-east Australian mainland. DArTseq data are used to build a phylogeny including E. baueriana and closely related taxa to test its monophyly, test the genetic distinctness of the three subspecies of E. baueriana, and investigate relationships between its disjunct populations. Additionally, we use population structure analysis to investigate the genetic distinctness of populations, and MaxEnt to investigate the environmental factors potentially influencing the species' distribution. We show E. baueriana is monophyletic and most closely related to three other Blue Box eucalypt species: E. conica H.Deane & Maiden, E. dalveenica T.L.Collins, R.L.Andrew & J.J.Bruhl and E. magnificata L.A.S.Johnson & K.D.Hill, with some evidence for genetic introgression between these taxa. Within E. baueriana, the deepest genetic breaks do not correspond with the subspecies classification as the two geographically restricted subspecies, together with samples of the more widespread E. baueriana subsp. baueriana from west of the Gippsland lowlands, form a south-western clade with that is sister to other populations of subsp. baueriana. The oldest genetic break in the species occurs in far eastern Gippsland (Victoria), corresponding to one of the shortest geographic disjunctions in the species' distribution. Genetic breaks in other species have been observed in this region which is broadly referred to as the southern transition zone. Both total annual rainfall and the seasonality of this rainfall are hypothesised to affect the species' distribution; gaps in its distribution are in areas of higher rainfall that support closed forest and in regions with more winter dominated rainfall

Ribosomal DNA pseudogenes are widespread in the eucalypt group (Myrtaceae): implications for phylogenetic analysis

Pseudogenes from the 18S-5.8S-26S cistron of nuclear ribosomal DNA are reported in the eucalypt group (Myrtaceae), which includes seven genera. Putative pseudogenes are identified by a range of sequence comparisons including: the number of CpG and CpNpG methylation sites, GC content, estimated secondary structure stability of internal transcribed spacer transcripts, the presence of conserved motifs, patterns of sequence relationships and inferred substitution patterns. These comparisons indicate that pseudogenes are widespread, being evident in 'Eucalyptus' (subgenera 'Eucalyptus' and 'Eudesmia'), 'Corymbia' (extracodical sections 'Rufaria, Ochraria and Blakearia'), 'Angophora, Stockwellia quadrifida' and 'Arillastrum gummiferum'. At least six sequences used in previous phylogenetic studies are identified as pseudogenes, and a further 10 pseudogenes are newly sequenced here. Gene trees place pseudogenes in a number of distinct lineages: pseudogenes from Eucalyptus group with other Eucalyptus sequences, those from 'Corymbia' and 'Angophora' group with other 'Corymbia/Angophora' sequences, that from Stockwellia groups with other sequences from the Eucalyptopsis group, and that from 'Arillastrum' is placed as sister to the other included sequence of 'Arillastrum'. Some pseudogenes in Eucalyptus, 'Corymbia' and 'Angophora' represent "deep" ribosomal DNA paralogues that pre-date species differentiation in these groups, and a recombination analysis shows no evidence of recombination between putative pseudogenes and their functional counterparts. The presence of divergent paralogues presents both challenges and opportunities for the reconstruction of eucalypt phylogenies using ribosomal DNA sequences. Phylogenetic data sets should include only orthologous sequences, but different paralogues potentially provide additional, independent, character sets for phylogenetic analyses