IV] PRESERVATION OF PLANTS 67 



vegetation, but, by the application of the knowledge 

 of the relation between the structure of the plant- 

 machine and its functions gained by a study of living 

 species, it is possible in some degree to picture the 

 plants of the Coal period as living organisms and 

 to see in the structural framework a reflection ot 

 external environment. The recognition in the general 

 architectural plan of the Palaeozoic plants, as in 

 many of the finer anatomical features, of the closest 

 resemblance to plants of the modern world produces 

 an almost overwhelming sense of continuity between 

 the past and the present. 



The plants of the Palaeozoic period, though often 

 diffbring considerably from those of the same class 

 in the floras of to-day, exhibit a remarkably high type 

 of organisation. Some of the most abundant trees in 

 the forest of the Coal age are decidedly superior 

 in the complexity of their structure, as also in 

 size, to modern survivals of the same stock. On 

 the other hand, it must be remembered that Mono- 

 cotyledons and Dicotyledons which now occupy the 

 highest place in the hierarchy of plants have left no 

 sign of their existence in any of the Palaeozoic strata. 

 The greater size of some of the Palaeozoic plants, 

 and in some respects the more advanced stage of 

 evolution which they represent as compared with 

 their nearest relatives of the present era, must be 

 considered in relation to their more important and 



5—2 



