264 O. Feistmantel 



Dicótyledons occur usually quite rarely, and are mostly archaic in 

 character. At other localities, however, the Jurassic feature is much 

 diminished, the proportions of Ferns, Cycads, Conifers and Equiseta 

 is much smaller, and Dicótyledons are more abundant. At these loca- 

 lities the Dicótyledons with the most modern aspect occur. 



Notwithstanding this difference in the flora, the conformability 

 of the beds, and the number of plants common to all, forbid a se- 

 paration into distinct members. 



The archaic character of some of the Dicótyledons has been al- 

 luded to. By this is meant a character including the following fea- 

 tures. The nervation is lax and irregular. It is noteworthy for the 

 slenderness of the primary lateral nerveš, or ribs and for the com- 

 parative strength and fern-like character of the ultimate reticulation ; 

 in a number the petiole, which seems to háve been rather succulent, 

 splits up into a number of nearly equal nerveš. These characters 

 are independent of the comprehensiveness of type possessed by so 

 many of the Potomac Dicótyledons. This latter is indicated by the 

 outline of the leaf, its mode of division, etc. 



The following are the genera of Dicótyledons. Most of them are 

 so vaguely characterized, or so complex in type that it is very dif- 

 ficult to refer them to any single living relatives. 



List of genera. 



Conospermites 







1. 



Species.*) 



Acaciaephyllum 



gen. 



nov. 



4. 



5) 



Proteaephyllum 







8. 



)} 



Rogersia 



5J 



» 



2. 



11 



Sassafras 







3. 



n 



Fícophyllum 



5J 



i> 



4. 



» 



Ficus 







2. 



11 



Sapindopsis 



» 



t> 



8. 



11 



SálicipTiyllum 



55 



11 



3. 



» 



Celastrophyllum 



5! 



)) 



9. 



» 



Querciphyllum 



11 



11 



2. 



n 



Vitiphyllum 



11 



» 



3. 



n 



Myrica 







1. 



?7 



*=) Lester Ward giebt in seinem Aufsatze die Žahl der Arten als 76; hier er- 

 geben sich nur 73, was jedoch an dem Interesse des Gegenstaades gar 

 nichts ándert. Die ZaH 73 ist immerhin hoch genug. 



