Glossoptera Leaves, NSW
Glossopteris was a woody, seed-bearing shrub or tree, some apparently reaching 30 metres (98 ft) tall. They had a softwood interior that resembles conifers of the family Araucariaceae. Seeds were borne on one side of variably branched or fused structures, and microsporangia containing pollen were borne in clusters at the tips of slender filaments. Both the seed- and pollen-bearing organs were partially fused (adnate) to the leaves, or, in some cases, possibly positioned in the axils of leaves. The homologies of the flattened seed-bearing structures have remained particularly controversial with some arguing that the fertile organs represent megasporophylls (fertile leaves) whereas others have interpreted the structures as flattened, seed-bearing, axillary axes (cladodes). It is unclear whether glossopterids were monoecious or dioecious.
The first investigation of a Glossopteris flora associated with coal seams within a paleogeographic and palaeoclimatic context, in the Paraná Basin, southern Brazil, was that by geologist Israel Charles White in 1908. This allowed correlation between Gondwanan coal deposits in southern Brazil and those documented in South Africa, Australia, India andAntarctica, and showed that this flora flourished in latitudes near the south pole.
In Rio Grande do Sul, Glossopteris leaves were found in paleorrota at Mina Faxinal, in Arroio dos Ratos at Mina Morro do Papaléo in Mariana Pimentel and Quitéria in Pantano Grande. Various species were recovered from the Rio Bonito Formation at these sites including G. angustifolia, G. brasiliensis, G. browniana, G. communis, G. indica and G. occidentalis.