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many as three or four, contiguous rows of pits on their 

 radial walls, and these appear in surface view as 

 flattened circles or polygonal areas. 



These details have been mentioned in order to show 

 that Araucaria and Agathis are sufficiently distinct 

 in many respects from other Conifers to render their 

 identification in a fossil state comparatively easy, at 

 least much easier than the recognition of the majority 

 of the members of the Coniferae. It would be going 

 too far to state definitely that Araucarieae, as defined 

 by reference to existing species, existed during the 

 Palaeozoic period ; on the other hand it would seem 

 in a high degree probable that the vegetation of the 

 Coal age and of the succeeding Permian period in- 

 cluded trees in which certain Araucarian characters 

 were clearly foreshadowed. The name Araucarioxylon 

 was formerly applied to petrified wood, obtained from 

 Palaeozoic as well as from later formations, which 

 agrees anatomically with that of Araucaria and Agathis. 

 It has been shown in recent years that much of the 

 Palaeozoic wood of this type of structure belongs 

 to the extinct genus Cordaites, a tree which played 

 a prominent part in the earlier floras. Cordaites 

 affords a good example of a generalised type : in 

 its wood-structure it resembles very closely the 

 existing Araucarieae ; its long strap-like leaves are 

 not unlike those of some species of Agathis ; its 

 male flowers have often been compared with those 



