DESCRIPTIONS OF SPECIES. 101 



Liquidainbar of the Atlantic coast of North America, and the capsules 

 are smaller. The leaves of Liquidambar are found generally distributed 

 through the Middle Tertiary of Europe and have been described from 

 many localities. They exhibit a great diversity in size and form, as is true 

 of the living species above referred to, and it is the opinion of Heer and 

 Schimper that this is the descendant of the fossil one. 



Lesquereux has described a species of Liquidambar from the Pliocene 

 deposits of Chalk Bluff, California,, which he regards as distinct from 

 L. Europceum. The largest specimen which he figures has almost exactly 

 the form of those before us, but he says that they are usually small, and 

 three-lobed. Probably this also is to be regarded as only a variety of 

 L. Europceum, and all forms as hardly distinguishable from the living 

 L. styraciflua. This species is quite variable. In northern Mexico the tree 

 and leaves are small and the latter are all three-lobed. In Louisiana the 

 Sweet Grum often forms the greater part of the forest growth; the trunk 

 attains the height of 60 to 80 feet, with a diameter of 2 to 3 feet. The 

 tree grows along the coast as far north as Massachusetts, and has leaves 

 6 to 7 inches in diameter. They are generally five-lobed, but I have 

 found on the same tree leaves that were three-, five-, and seven-lobed. 



Formation and locality : Tertiary (Miocene). Bridge Creek, Oregon. 



Liquidambar obtusilobatus (Heer) Hollick. 

 PI. V, fig. 4; XII, fig. 4. 



Pliyllites obtusilobatus Heer. Proc. Acad. Nat. Sci. Phila. (1858), p. 266. 



Acerites pristinus Newb. Ann. N. Y. Lye. Nat. Hist., Vol. IX (April, 1S68), p. 15. 



Liquidambar integrifolius Lesq. Am. Journ. Sci., Vol. XL VI (July, 1868), p. 93; 



Cret. Fl. (1874), p. 56, PI. II, figs. 1-3; XXIV, fig. 2; XXIX, fig. 8; Ills. 



Cret. and Tert. PI. (1878), PI. V, fig. 4, under Acerites pristinus. 



This is the leaf first described by Professor Heer, from an outline 

 sketch, in the Proceedings of the Academy of Natural Sciences, Philadel- 

 phia, 1858, page 266, under the name of Pliyllites obtusilobatus. When, 

 in 1868, the Later Extinct Floras of North America was published, an 

 imperfect specimen was described by the writer as Acerites pristinus. 

 Subsequently several much better specimens were obtained by Lesque- 

 reux which led him to refer it to the genus Liquidambar. His descrip- 

 tion is given in American Journal of Science, Vol. XLVI (July, 1868), 



