DESCRIPTION OF THE SPECIES. 289 



SASSAFRAS Nees. 



The genus Sassafras seems to Iiave been certainly present in tlie 

 Potomac flora in forms that differ little from the living species, and in at 

 least one species the fossil leaves can be matched by the living plants 

 which "abound in the vicinity. The genus, however, is sparingly repre- 

 sented l)otli in species and individuals. Remarkably few specimens of 

 undoubted Sassafras were found. 



Sassafras pakvifolium, sp. nov. 



Plate CXXXIX, Fij,'. 7. 



Leaf very small, shape not seen. At the summit there is an obtusely 

 rounded short lobe, and on each side of this occur two oval subacute lobes 

 which are imperfectly shown, owing to mutilation. 



Locality: Covington street, lialtimore, very rare. 



Sassafras cretaceum, Newb., var. heterolobum. 



Plate CLII, Fig. 5; Plate CLIX, Fig. 8; Plate CLXIV, Fig. 5. 



Leaves small, but varying somewhat in size, wedge-shaped at base, 

 expanding rapidly above so as to assume a fan-shape, having at the sum- 

 mit three lobes, which extend nearly to the same height, but are very shal- 

 low. The middle one has its margins parallel with the midrib for the 

 greater portion of its length, but at its summit it is abruptly rounded and 

 very obtuse, or else narrows to a sul)acute point; the lateral ones are sep- 

 arated from this by a rather broad, rounded sinus, and have their tijis more 

 or less divergent, subacute, pretty 1)road, with the outer margin curving 

 gently and the inner nearly straight. The petiole seems to have been 

 strong, and soon after entering the leaf it splits into three nerves, one 

 medial and two lateral ; lateral nerves going off obliquely at nearly the 

 same point and running nearly straight into the lateral lobes, each sending 

 off on the outer side, near the base and at the same height, two strong 

 branches, that curve upwards ; lateral nerves at higher points and the mid- 

 nerve throughout, sending off obliquely lateral nerves that are much 

 smaller than the two lower outer ones. Subordinate nerves and reticula- 

 MON XV 19 



