76 



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required here. I will only say in passing that the Carboniferous flora 

 of America exhibits the same botanical characters as that of the Old 

 World. A few genera and a large number of species are peculiar to 

 America, but in all the great collections of fossil plants gathered from 

 the coal strata of this country, there is perhaps no botanical ele- 

 ment which has not also been noticed in Europe. It is impossible 

 now tp say how many species of plants have been obtained from our 

 American Carboniferous rocks, for the literature of the subject is cum- 

 bered with much synonymy, and species have been multiplied by de- 

 scribing under distinct names the stems, leaves, and fruit of the same 

 plant ; but at least five hundred distinct species have been described, 

 and that number is being added to every year. Of those already 

 known, probably half should be considered identical with some of 

 those found in Europe; and in some strongly marked and well-known 

 species the identity is so complete that we cannot but wonder at the 

 potency of the vital influence which held so closely to an elaborate 

 pattern, organic structures inhabiting different quarters of the globe. 

 The Triassic and Jurassic floras were essentially alike in botani- 

 cal characters. They both show a complete and surprising revolu- 

 tion in the vegetation of the globe in the passage from the Palaeozoic 

 to the Mesozoic ages. By influences of which up to the present time 

 we are ignorant, the great acrogenous flora of the Devonian and Car- 

 boniferous—consisting of gigantic lycopods and equiseta, the peculiar 

 group of sigillarids, a few simple-leaved cycads, and many ferns- 

 passed away " like a tale that is told " and, instead, without known 

 transitional forms, arose the great cycadaceous flora of the Mesozoic 

 Here the lycopods have shrunk to insignificance, the sigillarids are 

 extinct, the calamites with their allies, Annularia and Sphenophyllum 

 are replaced by true Equiseta, the conifers and cycads multiplied until 

 they constitute the most conspicuous forms of vegetation These 

 conifers were Araucarians; some with close rhomboidal appressed 

 disks for leaves {Brachyphyllum), others with divergent fleshy 

 scales {Alberha) like the Brazilian Araucaria of the present day and 

 still others with filiform foliage like the modern spruces ( Volizia ) 

 The cycads were almost infinitely varied. Some were arborescent 

 with lofty trunks crowned with graceful canopies of nodding plume- 

 hke fronds, while others grew in spheroidal masses marked with rhom- 



^'.V^ . .7^^'"''- J"/^^'-?S ^Z ^^^ ^'"^ discoverer gigantic birds' nests 

 {Mantelha mdifonnts). Remarkable changes are also noticeable in 



the/erns. Those with highly compound ixonds {SphenoMeris, Pecop- 

 terts, etc.), which existed m such vast numbers in the Carboniferous 

 age were to a great degree superseded by those with simple linear or 

 spatulate fronds {Taemopteris\ and by those in which the stipe bore a 

 horizontally-expanded pedate or spiral frond {Camptopteris etc ) or 

 broad pinnate or radiate fronds, like Clathropteris, of which the sur- 

 """k?' ?'l^f^,J"*° rectangular areoles by the strong nervation. 



f£ 



aeo- 



zoic ages and had jittle resemblance to any that are now living 



Abundant remams of the Triassic flora are found in the rocks of 

 this age at Richmond, North Carolina, in New Jersey and Tn the 

 Connecticut Valley. In certain localitie's vegetation wa^'so luxuriant 



