Agathoxylon

Agathoxylon (previously known as Dadoxylon) is a form genus of araucarian fossil wood, including massive tree trunks. Although identified from the late Palaeozoic to the end of the Mesozoic, "Agathoxylon" is common from the Carboniferous to Triassic.
Description.
"Agathoxylon" were large trees that bore long strap-like leaves and trunks with small, narrow rays. Often the original cellular structure is preserved as a result of silica in solution in the ground water becoming deposited within the wood cells. This mode of fossilization is termed permineralization.
Systematics.
As a genus, "Dadoxylon" was poorly defined, and apart from Araucariaceae, has been associated with fossil wood as diverse as Cordaitales, Glossopteridales and Podocarpaceae. Furthermore, it may be the same form genus as "Araucarioxylon", hence the usage "Dadoxylon" ("Araucarioxylon"). The genus "Agathoxylon", classified under the family Araucariaceae, has nomenclatural priority over the genera "Araucarioxylon" and "Dadoxylon".
Several "Dadoxylon" species, such as "D. brandlingii" and "D. saxonicum" have been identified as "Araucarites". "D. arberi" and "D." sp.1 were synonymised with the glossopterid species "Australoxylon teixterae" and "A. natalense", respectively; while "D." sp. 2 was transferred to "Protophyllocladoxylon".
Distribution.
"Agathoxylon" is common in many parts of the world, found in sites of both Gondwana and Laurasia and reported from southern Africa, Asia, the Middle East, Europe, South America, and North America.
In southern Africa, "Agathoxylon" is widespread in the Karoo Supergroup. In Zimbabwe, it is especially encountered in the Pebbly Arkose Formation, and also reported frequently from the Angwa Sandstone Formation.