IG MEMOIRS FROJI THE DEPARTMENT OF BOTANY OF COEUMBIA COLLEGE. 



[Plate A.] 



I. Polygonum tertiarium. 



Slender. Stem striate and somewhat angled, much enlarged and sparingly gnarled 

 at the nodes, 4 mm. in diameter above the ocrea, 3.5 mm. above the node, and 8-9 mm. 

 at the node ; leaf lanceolate, entire, apparently acutish at the apex, sub-cordate at the 

 l)ase, petioled, the lamina 6 em. long, 2.6 cm. broad, apparently slightly undulate, the 

 midrib about l.o mm. broad at the base, the secondary nerves opposite or alternate, 

 leaving the midrib at angles \'arying from 40 to 45 degrees, soon curving upward, camp- 

 todrome, sometimes coalescing at a point about halfway to the ixiargin or forking a short 

 distance from the midrib, joined b}' tertiary' cross-nerves, which leave the secondary one 

 at almost a right angle; petiole 2 cm. long, 1.5 mm. broad at the junction with the 

 lamina, somewhat expanded and 4 mm. broad at the base, joined above the middle of the 

 ocrea ; ( )cren cylindric, .'5 cm. long, irregular at the summit. 



In the Miocene Tertiary at Florissant, Colorado. 



