Marks, Claire .
Floral morphology and Australian Nicotiana.
NICOTIANA section Suaveolentes is monophyletic and endemic to Australia with one or two taxa in the South Pacific and one in Africa. Approximately 25 Australian species occur across the continent in a variety of habitats but mostly in arid areas. The phylogeny of the section has not been resolved by molecular work to date, and many taxa are under collected and poorly known. A number of species and subspecies are difficult to identify in the field and the current taxonomy is problematic. My studies have shown that floral characters are useful for defining the Australian taxa of Nicotiana. Twenty-one floral characters have been analysed for 230 specimens using UPGMA cluster analysis and ordination. Eighteen clusters correlated with recognised species and subspecies. However some current taxa overlapped and are not seperated on floral characters. Important floral characters are: floral tube length, stamen length, calyx length and width, diameter of petal limb and the percentage of the shortest stamen that is free. These flower data form part of a larger project to elucidate the phylogeny of the section based on morphology. Scanning Electron Microscopy of trichomes also illustrates the potential usefulness of microanatomical characters.
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1 - The University of Melbourne, School of Botany, Parkville, Victoria, 3010, Australia
Location: Ballroom CD/Monona Terrace
Date: Tuesday, July 25th, 2006
Time: 8:00 AM