Ontogeny, anatomy and systematic significance of ovular structures in the 'eucalypt group' (Eucalypteae, Myrtaceae)

Abstract

Development of ovular structures in the 'eucalypt group' (Eucalyteae, Myrtaceae) was investigated using scanning electron microscopy and light microscopy. Different modes of placental expansion account for the variation in initiation and arrangement of ovules and ovulodes. In Eucalyptus sensu stricto placental elongation proceeds proximally and the distally-positioned ovulodes develop from the first primordia initiated (congenital ovulodes). In Angophora, Corymbia, Arillastrum, Allosyncarpia and Stockwellia placental elongation is bi-directional and the ovulodes develop from last-initiated primordia (residual ovulodes). Bi-directional elongation and residual ovulodes are present in the outgr..