^°i89o!"'] PROCEEDINGS OF THE NATIONAL MUSEUM. 25 



of the supposed Liriodendron ohlongifoUuin, qiiercifoUmn, simplex, and 

 others. 



Now as regards the fossil leaves, belonging to the genus Lirioden- 

 dron^ all of them have been found either in the Cretaceous or in 

 the Tertiary formation. They represent certainly several quite well- 

 distinguished forms, but whether they represent a corresponding num- 

 ber of species is rather doubtful, at least, if we will compare them with 

 the numerous variations, which, as stated above, occur even on the same 

 tree, the only recent species of our flora. These supposed species are : 



Liriodendron acuminatum Lesqx. 

 Liriodendron Celalcoi-shii Veleusk. 

 Liriodendron cruciforme Lesqx. 

 Liriodendron Gardneri Sap. 

 Liriodendron gigantcum Les(ix. 

 Liriodendron Hauerii Ettings. 

 Liriodendron laramiense Ward. 

 Liriodendron Meekii Fleer. 

 Liriodendron Meekii, var. gemiina. 

 Liriodendron Meekii, var. Marcouana. 

 Liriodendron Meekii, var. mucronnlata. 

 Liriodendron Meekii, var. ohcordata. 

 Liriodendron Meekii, var. primawa. 

 Liriodendron oblongifoUum Newb. 

 Liriodendron pinnatifidnm Lesqx. 

 Liriodendron Procaccinii, Ung. 

 Liriodendron Procaccinii, var. A, Helvetica. 

 Liriodendron Procaccinii, var. B, acutiloha. 

 Liriodendron Procaccinii, var. C, ohtusiloha. 

 Liriodendron Procaccinii, var. C, (1) snbattenuata. 

 Liriodendron Procaccinii, var. C, (2) rotundata. 

 Liriodendron Procaccinii, var. D, incisa. 

 Liriodendron quercifoUum Newb. 

 Liriodendron scmialatnm Lesqx. 

 Liriodendron simplex Newb. 



besides the Tertiary, considered as identical with our recent Lirioden- 

 dron Tulipifera L. 



We have here fourteen species, with, in all, eleven varieties enumer- 

 ated of a genus, of which but one is still existing, i)roperly indigenous 

 in North America and China. We shall see later that, while some 

 authors have not hesitated to consider the different forms as species, 

 others have preferred to describe several of them as merely vari- 

 eties. The geographical distribution of the Tulip-tree was certainly 

 wide in the Cretaceous age, when it existed as far north as Greenland, 

 and in the Tertiary formation it occurred in several parts of Europe 

 from Iceland as far south as Italy. It is not strange then that a 

 genus, scattered throughout many lands during two geological epochs, 

 should have been represented by different forms, even specifically 

 distinct. On the other hand, it must not be forgotten that there is 

 very often to be observed a certain difference in the same plant when 

 we compare its representatives from different countries with varied 



