Developmental and Structural Section
Lewis, Emma .
Cuticular variation and leaf evolution in the tribe Eucalypteae (Myrtaceae).
The tribe Eucalypteae (syn. ‘eucalypt group’) includes seven genera of the family Myrtaceae that form a monophyletic group. Eucalyptus (600+ species), Angophora (13 species) and Corymbia (100+ species) are widespread in arid areas of Australia. The remaining four genera are of relictual rainforest distribution, with two Australian genera (Allosyncarpia and Stockwellia) and two extra-Australian genera (Eucalyptopsis and Arrilastrum). The fossil record of the group is problematic, with only limited leaf fossil evidence found to be similar to extant eucalypt leaves. A survey of 75 extant taxa using light and electron microscopy was undertaken in order to assist in the identification of eucalypt leaf fossils. Features of the leaf including cuticular ornamentation and stomatal structure were observed. A set of leaf cuticular characters that are definitive at a generic and sub-generic level within the group are described and illustrated alongside the corresponding cross-sectional leaf anatomy of each cuticular type. For each type, ontogenetic sequences from seedling leaf to adult are illustrated. These results will assist the identification of eucalypt leaves in future palaeobotanical studies and provide additional leaf characters for future taxonomic studies. By combining the results of this research with current molecular and morphological phylogenetic studies of the eucalypt group, possible modes of leaf evolution are proposed.
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1 - University of Melbourne, School of Botany, Reception, Parkville, Victoria, 3010, Australia
Presentation Type: Poster:Posters for Sections
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM