Cuticular morphology and aspects of the ecology and fossil history of North Queensland rainforest Proteaceae

Cuticles of North Queensland rainforest Proteaceae were examined using light and scanning electron microscopy. The genera of North Queensland rainforest Proteaceae are mostly endemic and composed of one or few species, with greatest diversity in the granitic uplands of the region. Knowledge of cuticular morphology may be an important tool in determining the true affinities of several undescribed taxa in the region and can be used to explore hypotheses relating to the history of the Proteaceae. Some species exhibit purported xeromorphic features of thick cuticles, sunken stomates and dense trichome cover on the abaxial surface. Grevillea , Banksieae and Stenocarpus are believed to have radiated into open, much less mesic environments. In the former two taxa this can be interpreted in terms of xeromorphic features expressed in their cuticular morphologies, whereas in Stenocarpus amphistomaty in species of open habitats suggests an alternative mode of evolution more related to physiological factors. Several Cainozoic proteaceous macrofossils temporally and spatially far removed from North Queensland possess cuticular morphologies very similar or identical to extant rainforest taxa in the region.