XVI International Botanical Congess

Androecial morphology differs widely amongst flowers of Australasian Myrtaceae. Differences occur in number, position and length and clustering of stamens. Similar structures in mature flowers are not necessarily equivalent in terms of their underlying development. Using detailed ontogenetic studies in Angophora, Eucalyptus, the Metrosideros group, Melaleuca, Callistemon and the Chamelaucium group we show how a range of developmental factors contribute to mature floral form. Timing of stamen production influences how many stamens are produced initially, total number of stamens in the flower is influenced by the duration of stamen intitiation, and the final arrangement of stamens is dictated by how the bud expands. Minor changes in any of these developmental factors result in significantly different flower morphology.