with Descriptions of JVew Sj>, <•/, s of Fossil J'/" "■: 



ous a feature in the flora to which it belongs, that it requires 

 to be figured and described. Future observations will deter- 

 mine whether it has been correctly referred to its livine allies. 

 Formation and Locality. Miocene strata. Banks of Yel- 

 lowstone River. (Dr. Hayden ) 



Negundo triloba (n. sp.) 

 Leaves thin and delicate, but distinctly nerved, pinnate in one 

 or more pairs, leaflets lanceolate or lance-ovate, long-pointed, rounded 

 or slightly cordate at base, short-petioled ; margins coarsely, re- 

 motely, and irregularly toothed; terminal leaflet trilobate, the mar- 

 gins toothed or serrated; nervation of lateral leaflets pinnate, nil i 

 or ten pairs of lateral nerves diverging from the midrib al an angle 

 of about 50°, arching upward, more or less branched toward the 

 summit. Of these the basal pair are shortest and Bimple, following 

 the course of the adjacent margin; the second pair are Btrono 

 and throw off each three or four curved branches on the lower side. 



The general aspect, including texture, form, dental ion, and 

 nervation of the lateral leaflets, is strikingly like thai of the 

 corresponding parts of the leaf of the living JY, gundo "<■< roidi 8. 

 The genus Negundo is represented among living plant- by hut 

 a single species, and this is so like Acer in all but its leave-, that 

 Prof. Gray intimates that it should hardly be considered die 

 tinct from that genus. A fossil species has been discovered 

 in the Tertiaries of Europe, N. Furqpeum, Heer (Flor. Tert. 

 Helvet. 3, S. 60, Taf. cxviii. figs. 20-22), but it would seem to 



have been a smaller species than the living i, and had 



obovate wedge-based leaves, quite different from those bel 

 us. 



If in the light of more and better material, it Bhonld pro 

 that a species of Negundo lived on the American contin 

 during the Miocene Tertiary Epoch, it would he a fact of no 

 little interest, and would strengthen the claim- \ gundo 



aceroides to a distinct generic place in the botanical B« In 



that case, however, its trilobate terminal leaflet wonld still 

 further indicate its acerine affinities. 



Formation and Locality. Near Fort tTnion. | Dr. Bayd< a.) 



