Format: ORAL

Raees Khan 1,2,3,*,Robert S. Hill1 and Jie Liu 2,3

1School of Biological Sciences, The University of Adelaide, Adelaide, SA 5005, Australia 2CAS Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China 3Germplasm Bank of Wild Species, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China

Conifers are economically and ecologically important and form extensive forests in both the Southern and Northern Hemispheres. The Podocarpaceae have evolved distinctive seed cones, most of which are fleshy. The detailed diversity and evolution of seed cones is poorly known in this family. We undertook a comparative analysis of Podocarpaceae seed cone morpho-anatomical traits and used ancestral state reconstruction to interpret their evolution. The family exhibits great diversity in functional structures and five distinct structures (free epimatium, fused epimatium, fleshy bracts, arils, and the receptaculum) are involved in the formation of their fleshy cones. Each of these structures has distinct evolutionary patterns, involving multiple origins and/or losses of fleshiness, with a minimum of 24 independent evolutionary changes either from non-fleshy to fleshy or fleshy to non-fleshy structures. The pathways of fleshy seed cone production vary among genera and sometimes within a genus. The Podocarpaceae show great evolutionary lability in seed cone morphology and especially in the production of fleshy seed cones, which are associated with the pollination mechanism (by assisting ovule inversion), protection of the ovule/seed and seed dispersal. The reconstruction of the ancestral Podocarpaceae seed cone is complicated by extinction, convergent evolution, and the relatively few fossil seed cone records.