898 SYSTEMATIC PALEONTOLOGY 



Populus apiculata Hollick, 1907, Mon. U. S. Geol. Survey, vol. 1, p. 49, pi. vii, 



figs. 28, 29. 

 Populus apiculata Berry, 1911, Bull. 3, Geol. Survey of New Jersey, p. Ill, 



pi. xi, fig. 4. 



Description. Leaves variable in size and shape, ovate to orbicular in 

 general outline, 5 cm. to 10 cm. in length by 3 cm. to 7 cm. in maximum 

 width, which is at or below the middle. Apex usually somewhat abruptly 

 produced into an acuminate tip. Base cuneate and slightly decurrent to 

 rounded or almost truncate. Margins entire, sometimes slightly repand. 

 Petiole of medium length, stout. Midrib mediumly stout, often flexuous. 

 Secondaries five or six pairs, subopposite below, alternate above, slender, 

 branching from the midrib at angles of from 45 to 50 and arching 

 upward, camptodrome. Tertiaries camptodrome in the marginal region, 

 percurrent internally. 



Professor Newberry, the original describer of this species in manuscript, 

 compared it with Populus hyperborca Heer and Populus berggreni Heer, 

 but seemed doubtful of its real relation to Populus. This doubt seems 

 to be well founded, for while these leaves are not unlike those usually 

 referred to the genus Populus, this assumed relationship has by no means 

 been proven for a number of the Upper Cretaceous forms so identified. 

 While it is not impossible that species of Populus may have flourished 

 from New Jersey to the Gulf region during the Upper Cretaceous, the 

 association of a number of forms whose descendants are tropical led to an 

 extended search among existing tropical American forms, with the result 

 that the present species is referred to the genus Cordia. The latter has 

 upwards of two hundred existing species of the tropics and warmer extra- 

 tropical regions of both hemispheres, the majority being American, several 

 of which reach the Florida Keys, the Bahamas, and the valley of the Rio 

 Grande. The fossil species in all its characters suggests most strongly the 

 existing Cordia sebestena Linne which ranges from the Florida Keys to 

 New Guinea. It also suggests Cordia tremula Griesbach of the West 

 Indies, and there is a general generic likeness to various other existing 

 species of this genus. Cordia leaves are variable and tend to have more or 

 less toothed margins as is sometimes the case in Cordia sebestena, but they 



