Alford, Mac H. , Brantley, Rebecca J. , Hernández, C. Liliana , Samarakoon, Tharangamala .
What are the closest relatives of Salix and Populus?
Recent studies have demonstrated that five Asian and two Central American genera formerly placed in the Flacourtiaceae are the closest relatives of Salicaceae sensu stricto (Salix and Populus). However, in all analyses the closest relative or relatives were unresolved. In order to elucidate these relationships, additional morphological and DNA sequence data were gathered for phylogenetic analysis. DNA sequence data were obtained from one nuclear region (ITS) and eight plastid regions (matK, ndhF, rpL16, trnD-trnT, trnH-psbA, trnL, trnL-F, trnS-trnG). Although two genera, Macrohasseltia and Olmediella, could not be amplified for all regions, the results indicate that a clade consisting of Bennettiodendron, Idesia, and Olmediella are sister to Salix and Populus. Sister to that clade is a clade of the other four genera, Carrierea, Itoa, Macrohasseltia, and Poliothyrsis. Morphologically, these relationships are sensible, as all seven genera lack petals, have similar glands at the leaf teeth, and have sepals that are caducous in fruit. In addition, the clade sister to Salicaceae sensu stricto consists of genera that are dioecious (or polygamous) and have stamens associated with nectaries (“disk glands”). Combined with recent fossil evidence from Salicaceae, these results indicate that the nectaries of Salix are homologous to nectaries, not to perianth.
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1 - University of Southern Mississippi, Department of Biological Sciences, 118 College Drive #5018, Hattiesburg, MS, 39406, U.S.A.
Presentation Type: Oral Paper:Papers for BSA Sections
Location: Maybird/Cliff Lodge - Level C
Date: Wednesday, July 29th, 2009
Time: 9:00 AM