Some Morphological Features of Wollemi Pine (Wollemia nobilis: Araucariaceae) and Their Comparison to Cretaceous Plant Fossils

Abstract

Morphological details of Wollemia nobilis (Wollemi pine) are described and illustrated, and compared with the extant genera Agathis and Araucaria and with selected araucarian fossils from the Cretaceous of Australia. Adult and juvenile shoots of Wollemia differ in leaf arrangement, leaf shape, and cuticular features; in these features they are most similar to Araucaria. The cone scales have a long, distal spine reminiscent of Araucaria section Eutacta, but the winged seeds that are ontogenetically free from, and shed independently from, the cone scale are similar to Agathis. Shoots with variable leaf types, Araucaria-like cone scales, and Agathis-like winged seeds are found in several plant fossil assemblages from the Cretaceous of Australia; these fossil conifers, which had been recognized as araucarian, can now be favorably compared with Wollemia. Pollen of Wollemia is indistinguishable from the fossil pollen form-genus Dilwynites, which has a fossil record extending back to the Late Cretaceous in Australia and New Zealand. Reexamination of Mesozoic and Tertiary paleofloras will most probably reveal an important contribution of Wollemia to the fossil record of Araucariaceae.