H. BOTANY AND HORTICULTURE. 361 



H. BOTANY. 



RELATION BETWEEN THE MODERN AND TERTIARY FLORAS. 



A communication was made to the Vienna Academy by 

 Ettingshausen, embodying bis extensive researches on ter- 

 tiary plant-fossils and their study in connection with modern 

 floras. Regarding the present vegetable world as the result 

 of a former preparatory condition, he proceeds upon the fact 

 that the modern floras were already prefigured in the tertiary 

 flora, not confined, however, as at present, to different distinct 

 regions ; but that plants, at present denizens of widely differ- 

 ent portions of the earth, then flourished in the same region. 

 The state of preservation of the fossils of temperate and sub- 

 tropical plants, often occurring even in the same piece of 

 rock, renders this fact inexplicable on the hypothesis of the 

 mingling of the floras of mountains and lowlands, and leaves 

 only the conclusion that these plants flourished in immediate 

 proximity. Hence the tertiary flora, in comparison with the 

 modern, may be regarded as a kind of compounded primitive 

 flora, which by resolving, as it were, into its elements, pro- 

 duced the present natural floras, each of which consists of a 

 principal element, and to a greater or less degree of second- 

 ary elements; the term "element" being understood to in- 

 clude all geological plant-forms, the analogues of which at 

 present belong exclusively to the region of one natural flora. 

 The tertiary flora, therefore, as it involved all modern floras, 

 was, so far, of the same character over the whole earth. In 

 the present flora then, regarded as the more fully developed 

 tertiary flora, there are of course plant-forms on which the 

 impress of the original elements may be recognized, although 

 somewhat altered. This is very evident, in regard to the 

 principal elements, but the effect of secondary elements in 

 the development of modern plants can also be inferred from 

 the relationship of many modern genera and species, as well 

 as from their distribution ; and components of the natural 

 floras, which do not seem to conform to the character of the 

 same, clearly betray their association with components of 

 the secondary elements ; and the more or less extensive 



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