Later Extinct Flora* oj Worth America, 



Aralia triloba, (n. sp.) 



Li aves pinnate or ternate; lateral leaflets long-oval, rounded, or 

 slightly heart-shaped, and unequal at base, pointed at summit, 

 sharply Berrate throughout ; nervation pinnate; texture thin; sur- 

 faces smooth. 



Trilobate leaf similar in surface, texture, nervation and marginal 

 ition, but unequally three-lobed; lobes acute, Long-pointed. 



The character of these leaves is vow well shown in the speci- 

 men- before me. They seem plainly to indicate a specie.- of 

 Aralia, and have a marked resemblance to some of the Leaves 

 of our two most common species, A. raoemosa and A. nudicau- 



1/18. Tiie trilobate leaf is not commonly found in our Aralia-. 

 hut there is, always a tendency to the production of such a form. 

 and I have frequently remarked it in A. racemosa, as it grows 

 at the West. That is, however, generally a much larger and 

 stronger plant than this. 



Formation and Locality. Miocene strata. Fort Clarke, 

 i I )r. Hayden.) 



< or> ins orbiculata. (n. sp.) 



Leaves small, orbicular, or nearly so, slightly and unequally cor- 

 date .-it base, blunt-pointed above ; margins set with tine and nearly 

 equal teeth; nervation Btrong; midrib curved and slightly sinuous; 

 lateral nerves about 7 pairs, mostly straight and nearly parallel 

 among themselves, lower pair sending off each 7—8 short, simple or 

 forked branches which terminate in the teeth of the edge; Becond 



pair supporting each ahoiit three brauche- of similar character: 



upper lateral nerves simple, or having each 2—3 branohes near the 

 Bummit ; tertiary nerves parallel, distinct. 



Tin- is another hazel like leaf, of which the classification, with- 

 out the fruit, mu-t he somewhat doubtful. The general form is 



more like that of the leaves of Tilia {'/'. Americana ami '/'. 



EuropCBa)', being much rounder than those of any species of 

 ' rylue with which 1 am familiar. 



The nervation is however different fr that of TUia, and 



n facl altogether that of Corylw. In Tilia, the leave- are 



