96 THE LATER EXTINCT FLORAS OF NORTH AMERICA. 



LlRIODENDEON PKIMiEVUM Newb. 



PI. VI, fig. 7. 



Ann. N. Y. Lye. Nat. Hist., Vol. IX (April, 1868), p. 12; Ills. Cret. and Tert, PI. 

 (1878), PI. VI, fig. 7. [Not named on plate.] 



"Leaves three-lobed, upper lobe emarginate, all the lobes rounded; 

 nervation delicate, principal nerve straight or slightly curved, terminating 

 in the sinus of the superior lobe ; secondary nerves gently arching upward, 

 simple or forked near the extremities, a few more delicate ones alternating 

 with the stronger." 



Collected by Dr. F. V. Hayden. 



This leaf is considerably larger than that of L. Meekii Heer, less deeply 

 lobed, and the lobes more broadly rounded. In its general aspect this 

 species approaches much nearer the living tulip tree and the Tertiary species 

 of Europe (L. Procaccinii Ung.) than that described by Professor Heer 

 from the collections of Dr. Hayden (L. Meekii). The leaves of the former 

 species are, however, generally more deeply lobed and the lobes are acute, 

 but I have collected leaves of L. tulipifera of small size with all the, lobes 

 rounded and in all respects remarkably like that under consideration. On 

 the whole this is so like the leaf of our tulip tree that there can be little 

 doubt that it represents a species of the same genus which grew on our 

 continent at the commencement of the Cretaceous epoch. This is one of 

 the most important facts deduced from the collections of Dr. Hayden, for 

 the genus Liriodenclron is now represented by but a single known species, 

 which is confined to North America. During the Miocene Tertiary epoch, 

 however, it formed part of the flora of Europe, as well preserved leaves of 

 a species very closely allied to, if not identical with, the living one grew 

 in Italy, Switzerland, and Iceland. 



Thus this comes into the interesting category of Magnolia, Liquidam- 

 bar, Sassafras, etc., genera which flourished both in Europe and America 

 during the Miocene epoch, but which have long since ceased to exist on the 

 European continent. 



These specimens also teach us the still more interesting truth that 

 Liriodenclron, Sassafras, Magnolia, Quercus, Salix, Platanus, Populus, and 

 many others of our living genera date back on this continent to a period 

 long anterior to the dawn of the Tertiary age, and having survived all the 



