| Summary: | The structure and species richness of the Late Cretaceous (Santonian-Maastrichtian) vegetation in the Otway Basin, southeast Australia is reconstructed based on knowledge of palaeolatitudes, palaeotemperatures, plant taxa identified from fossil spores and pollen, and ecophysiological relationships established for present-day ecosystems. The vegetation, which grew at palaeolatitudes of 60-65°S and at mean annual palaeotemperatures of 16.5-19°C, comprised tall open-forests (Foliage Projective Cover 60-70%, height about 30 m) containing austral conifer and proteaceous taxa having coriaceous, notophyll-sized leaves. Today the taxa (Podocarpus, Dacrydium, Dacrycarpus, Knightia, Gevuina, Macadamia) from a minor component of upland closed-forests (usually termed rainforests) of tropical northeast Australia and New Caledonia. A conical-shaped crown to the trees of the tall open-forests situated in high latitudes during the Cretaceous would enable some light to penetrate the canopy to a shrubby understorey (of Proteaceae, Winteraceae, Trimeniaceae, Nothofagus, and Ilex) and a ground stratum of diverse cryptogams. On nutrient-poor, waterlogged sites fringing the forest, sclerophyllous leaved taxa (Adenanthos, Stirlingia, Epacridaceae, and possibly Beauprea) developed, with wetland swamps of Callitriche, ferns and some epacrids. In cooler localities in New Zealand and Antarctica, the productivity of the forests would have been greater, and the canopy taxa mainly with coriaceous, microphyll-sized leaves. Austral podocarps and Proteaceae occurred in the canopy of New Zealand forests, whereas the canopy of Antarctic forests contained podocarps and Nothofagus.
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