Dombeya

Abstract: The floristic composition and vegetation structure of Denkoro forest, South Wello Zone of Amhara Region, N Ethiopia, were described during November–December, 2002 A total of 95 sample plots were analysed, and 174 species of vascular plants representing 66 families were recorded Out of these, 41 species were new records reported for the first time from Wello Eleven endemic species, which are included in the IUCN Red List categories, have been recorded Based on the results of vegetation classification, six clusters were recognized and designated as local plant community types: 1) Erica arborea - Hypericum revolutum, 2) Myrsine melanophloeos - Dombeya torrida, 3) Myrsine africana – Maesa lanceolata – Prunus africana, 4) Olinia rochetiana – Olea europaea, 5) Olinia rochetiana – Allophylus abyssinicus – Apodytes dimidiata , and 6) Maytenus gracilipes – Teclea nobilis Structural analysis of the forest showed the density of individuals > 10 cm DBH to be almost twice as that of individuals with DBH >20 cm A higher proportion of woody individuals (ca 65%) fell in the low height classes (ie, SINET: Ethiopian Journal of Science Vol 29(1) 2006: 45–56

Abstract: Previous research suggests that Gossypium has undergone a 5- to 6-fold multiplication following its divergence from Theobroma. However, the number of events, or where they occurred in the Malvaceae phylogeny remains unknown. We analyzed transcriptomic and genomic data from representatives of eight of the nine Malvaceae subfamilies. Phylogenetic analysis of nuclear data placed Dombeya (Dombeyoideae) as sister to the rest of Malvadendrina clade, but the plastid DNA tree strongly supported Durio (Helicteroideae) in this position. Intraspecific Ks plots indicated that all sampled taxa, except Theobroma (Byttnerioideae), Corchorus (Grewioideae), and Dombeya (Dombeyoideae), have experienced whole genome multiplications (WGMs). Quartet analysis suggested WGMs were shared by Malvoideae-Bombacoideae and Sterculioideae-Tilioideae, but did not resolve whether these are shared with each other or Helicteroideae (Durio). Gene tree reconciliation and Bayesian concordance analysis suggested a complex history. Alternative hypotheses are suggested, each involving two independent autotetraploid and one allopolyploid event. They differ in that one entails an allopolyploid origin for the Durio lineage, whereas the other invokes an allopolyploid origin for Malvoideae-Bombacoideae. We highlight the need for more genomic information in the Malvaceae and improved methods to resolve complex evolutionary histories that may include allopolyploidy, incomplete lineage sorting, and variable rates of gene and genome evolution.