No snow in the mountains: early Eocene plant fossils from Hotham Heights, Victoria, Australia

Abstract

An Early Eocene plant assemblage from near the summit of Mt Hotham, Victoria, is described, using a combination of macro- and microfossils, especially cuticles. This is important since no other Australian macrofossil sites from this time, when environmental conditions are believed to have been the warmest of the Cenozoic, have been described in detail. The nature of the flora and vegetation supports geological evidence that the site was upland (approximately 800 m above sea level) at this time, with climatic conditions similar to those now experienced in regions such as the Atherton Tablelands in Queensland and mid-montane Papua New Guinea. The vegetation was probably a form of rainforest dominated by mesotherm elements, with abundant ferns including Gleicheniaceae and the tree ferns Cnemidaria, Cyathea and Dicksonia. Gymnosperms included Araucariaceae (Agathis) and Podocarpaceae (at least Acmopyle and Dacrydium). Angiosperms were diverse in Lauraceae (at least nine species including probably Cryptocarya, Endiandra and Litsea) and Proteaceae (at least nine species including probably Musgravea and Darlingia). Other angiosperms included Cunoniaceae, Gymnostoma (Casuarinaceae), Diospyros-like Ebenaceae, and the vine Cissocarpus (Vitaceae). Nothofagus was rare or absent from the Mt Hotham region at this time, as no macrofossil evidence was found, and pollen percentages were very low.