^°189o"''] PROCEEDINGS OF THE NATIONAL MUSEUM. 29 



tlie nervation of this leaf is so entirely different from what we have seen 

 of the recent and fossil species of Lirlodendron, since the leaf, figured by 

 Velenovsky, shows a typical palmate nervation, which is never to be ob- 

 served in the true geuus. It is a regular three-lobed leaf, of which the 

 middle lobe is a little emarginate. 



These fossil leaves of the European and Greenland Tulip-tree, which 

 we have considered, have exhibited the same kind of variation in the 

 leaves or foliage as our recent species. But it seems, as I have pointed 

 out above, that the leaves of i. Procacclnii have been usually attenu- 

 ated a little at the base, rather than showing the roundish form, which 

 is the most frequent in the recent type, and this character might prob- 

 ably be sufficient in distinguishing them as specifically differing from, 

 although closely allied to, our recent species. Another character is, as 

 has been observed by Heer, that some fruits found together with the 

 leaves of the variety Helvetica, were much smaller and differed in several 

 other respects from those of the recent type. We will now examine 

 the American representatives of the ancestral forms of Liriodendron. 



Several contributions have been })ublished upon these ancient types 

 by Lesquereux, Newberry, and Ward, and several species have been 

 enumerated by these authors as belongiug to this geuus. Leo Lesque- 

 reux has described L. intermedium * L. giganteum, L. acuminatum, L. 

 cruciforme, L. semialatum, and L. pinnatijidum, of which the last five 

 have been mentioned in his " Keport on the recent additions of fossil 

 plants to the Museum collections." t The author, unfortunately, has 

 figured only two of these six species, but his descriptions are suffi- 

 ciently clear to give a correct idea of the shape of these leaves. 



The first species, L. intermedium [l. c. PI. xx, Fig. 5), is a large leaf 

 which seems to have been deeply four-lobed, with the characteristic 

 notch at its apex, but the inferior part of the blade, as well as the outer 

 portion of the lobes, are entirely wanting. It probably represented 

 a form analogous to that shown on Plate vii. Figs. 26 to 30, but appar- 

 ently with narrower lobes. The other figure, given by Lesquereux in 

 his Cretaceous Flora, is of L. giganteum (/. c. PI. xxii, Fig. 2), which 

 shows only a mere lateral lobe of a very large leaf. He mentions, how- 

 ever, in his Report {I. c.) that a beautiful entirely preserved leaf has 

 been found of this si)ecies, of which the distance between the lower 

 pair of lobes is indicated as being 20'-'". The lower lobes are oblong, 

 obtuse, and very broad (0""), while the superior lobes are shorter, 

 slightly turned upwards, and joining the lower ones in an obtuse sinus 

 at a short distance of 2*^^'" from the midrib. This description shows a 

 form entirely differing from all those hitherto mentioned, and combines 

 as a parallel the leaves figured on Plate vii, Figs. 26 to 30, with the 

 very obtusely lobed form figured on Plate viii, Figs. 32 to 34. 



* L6o Lesquereux: Coutributions to the fossil flora of the Western Territories. 

 Part I. The Cretaceous Flora, 1874, p. 93. 



t Bulletin of the Mus. of Coiupar. Zoology at Harvard College, vii, No. G, 1881, p. 227. 



