Evolutionary and ecological significance of photosynthetic organs in <i>Phyllocladus</i> (Podocarpaceae)

Abstract The structure of phylloclades and true leaves in Phyllocladus was investigated with emphasis on function, ecology evolution. Only the earliest ontogenetic stages are true, needle developed. comprise a fusion product shoot axis first order its inserted leaves. Later, this is augmented by expansion axillary short shoots from base some fused Phylloclades mature individuals entire systems, including shoots, becoming photosynthetic tissue. These represent one adaptations for increasing functional area that present Podocarpaceae. Such were probably needed because Podocarpaceae usually medium-sized trees faced competition ever-expanding angiosperm forests at mid to high latitudes Southern Hemisphere Late Cretaceous, but especially during Palaeocene–Eocene, when dense diverse angiosperm-dominated rainforests common. data obtained living species compared those fossil material Phyllocladus. fully developed have been place since least early Cenozoic.