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80 



THE GEOLOGICAL HISTORY OF PLANTS. 



and durable wood, such as we have iu our modern pines 

 and yews (Fig. 29). 



These primitive pines make their appearance in the 

 Middle Brian, in various parts of America, as well as in 

 Scotland and Germany, and they are represented by wood 

 indicating the presence of several species. I have myself 

 indicated and described five species from the Erian of 

 Canada and the United States. From the fact that these 

 trees are represented by drifted trunks embedded in sand- 

 stones and marine limestones, we may, perhaps, infer that 

 they grew on the rising grounds of the Erian land, and 

 that their trunks were carried by river-floods into the sea. 

 No instance has yet certainly occurred of the discovery of 

 their foliage or fruit, though there are some fan-shaped 

 leaves usually regarded as ferns which may have belonged 

 to such trees. These in that case would have resembled 

 the modern GingTco of China, and some of the fruits re- 

 ferred to the genus Cardiocarpum may have been pro- 

 duced by them. Various names have been given to these 

 trees. I have preferred that given by linger, Dadoxylon, 

 as being more non-committal as to affinities than the 

 others.* Many of these trees had very long internal 

 pith-cylinders, with curious transverse tubulae, and which, 

 when preserved separately, have been named Sternhergia. 



Allied to these trees, and perhaps intermediate between 

 them and the Cycads, were those known as Cordaites 

 (Fig. 30), which had trunks resembling those of Dadoxy- 

 lon, but with still larger Sternhergia piths and an internal 

 axis of scalariform vessels, surrounded by a comparatively 

 thin woody cylinder. Some of them have leaves over a 

 foot in length, reminding one of the leaves of broad-leaved 

 grasses or iridaceous pi ts. Yet their flowers and fruit 

 seem to have been more nearly allied to the yews than to 

 any other plants (Fig. 31). Their stems were less woody 



* Araucaritca, Goeppert ; Arattearioxi/lon, Kraus. 



