6o BOTANICAL GAZETTE [july ; 



complete in the forms variously referred to L. Procacciiiii Unger, 

 Z. Haiieri Ettings., L, helveticum Fish-Oester, L. islaiidicufu Sap. 

 & Marion, all from the European Tertiary '^ formations, the 

 forms from the Pliocene being clearly identical with the existing 

 species. Schmalhausen''^ refers a leaf from the Pliocene (?) of 

 the Altai mountains to L, Tulipifera, and Saporta and Marion 

 consider certain of the forms referred to Z. islandicum as identical 

 with the modern tree. 



With the advent of the Glacial period the European Lirio- 

 dendrons, along with Sassafras, Magnolia, Celastrus, etc., dis- 

 appeared from that continent, the glacial conditions undoubtedly 

 forcing them southward until further retreat was cut off by the 

 Mediterranean. 



Returning to the curious lobate forms from the American 

 Cretaceous, we have four species and one variety that are unlike 

 anything seen in the modern species, and evidently not forming 

 a part of its ancestral line, but a collateral branch from it. The 

 most lobate forms found on the modern tree are quite different 

 from the long, narrow-lobed forms under consideration. The 

 least divergent form Is L. intermedium Lesq., and it is only known 

 from fragments of the upper part of the leaf. It was evidently 

 a large leaf, and might be derived from a form like L. giganteitm 

 by an extreme narrowing of the lobes. The next species, L. 

 Wellingtotdi Lesq., differs from the preceding in having the sup- 

 posed basal lobes of Z. interfnedium lengthened and curved 

 inward, ascending almost vertically nearly to the tips of the . 



upper lobes. L. acuminatum Lesq.' differs from Z. Wellingtoini in 

 having the basal lobes somewhat reduced in length and all of the 

 lobes acuminate. The variety bilobatiim merely differs from Z. 

 actimi7iatum in having the basal lobes bilobate, thus greatly 

 resembling various forms referred to Aralia. Lesquereux com- 

 pares it with Z. islandicum S. & M. If it be a true Lirlodendron 



'5 Diligent search fails to disclose Liriodendron in the extensive European Creta- 

 ceous system. 



^Ueber tertiare Pflanzen aus dem Thale des Flusses Buchtornia am fusse des 

 Altaigebirges. Palaeontographica 33. 1887. Z. Cetakovskii\^\^x\. is probably not a 

 Liriodendron (Bull. Torr. Bot. Club, July 1902). 



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