200 



THE GEOLOGICAL HISTORY OF PLANTS. 



of forms of these plants of a very striking character. It 

 is further to be observed that some of the genera have 



many species in the Cre- 

 taceous and dwindle to- 

 ward the modern. In 

 others the reverse is the 

 case they have expand- 

 ed in modern times. In 

 a number there seems to 

 have been little change. 

 Dr. dewberry has 

 given, in the " Bulletin 

 of the Torrey Botanical 

 Club," an interesting 

 resume of the history 

 of the beautiful Lirio- 

 dendron, or tulip-tree, 

 which may be taken as 

 an example of a genus 

 which has gone down 

 in importance in the 

 course of its geological 

 history. 



"The genus Lino- 

 dendron, as all botan- 

 ists know, is represent- 

 ed in the present flora 

 by a single species, ( the 

 tulip-tree,' which is con- 

 fined to eastern Amer- 

 ica, but grows over all 

 the area lying between 

 the Lakes and the Gulf, 

 the Mississippi and the 



FIG. ^.-Magnolia magnified, Dawson, Atlantic. It is a mag- 

 reduced. Upper Cretaceous, Canada. nificent tree, On the 



