210 THE FLORA OF THE DAKOTA GKOUr. 



of the lamina into linear, acute or obtuse lobes in L. acuminatum, L. Well- 

 inf/tonii, L. lyinnutijidum, etc., one is forced to admit, especitiUy from the 

 character of the nervation, that they pertain to Liriodendron. 



The fragments show the essential parts of what at first seem to be 

 compound leaves. The lobes on each side of the median nerve are sub- 

 opposite, about 5""" long, 1""° broad near the base, 17""° toward the apex, 

 where they are eitlier entire, obtuse, or lobate, separated Ijy a distance about 

 equal to that of their width, like the lobes of L. pinnatifidtnii, which, how- 

 ever, are not cut deep to the median nerve. This remarkalde species shows 

 more than any other of the genus the tendency to variability in the leaves 

 of the Dakota Group. 



Habitat: Ellsworth County, Kansas. No. 4 of the nuiseum of tlie 

 University of Kansas; A. Wellington, collect«»r. Fig. 2 is that of a speci- 

 men recently sent from Kansas, now in the collection of ^Ir. R. D. Lacoe. 



LlEIOPHYLLUM OBCORDATUM Lesq. 



PI. XXVIII, Fig. 7. 

 Cret. and Tert. Fl., p. 77. 



Leaf obovate, deeply emargiuate or split at apex, in the direction of 

 the midrib, narrowed and cuneate to the base; median nerve narroAv, rigid ; 

 secondaries few, thin, at an acute angle of divergence, simple, oblique, 

 effaced near the borders. 



This small leaf, by its deeply, narrowly emargiuate apex and l)y its 

 nervation, has its affinity more distinctly marked with Liriophyllum than 

 with Liriodendron. It is nearly S""" long, not quite \Jf"' broad in the upper 

 part, with two pairs of thin secondaries ascending liigli at an angle of di- 

 vergence of 30" and curving at a (Jistance from tlie borders ; the petiole is 

 destroyed. Though comparable to some of the figures given by Heer as 

 varieties (jf Liriodendron Meekii, it evidently differs in essential characters, 

 viz, the prolongation of the upper pair of secondaries to near the apex of 

 the upper borders or lobes of the leaf, as in those of LiriopltiiUnm populoides 

 Lesq. (Cret. and Tert. Fl., PI. xi. Figs. 1, 2). 



Habitat: Near Fort Harker, Kansas. S])ecimen in the Museum of 

 Comparative Zoology of Cambridge, Massachusetts. 



LlEIOPHYLLUM BEOKWITHII Lesq. 



Cret. aud Tert. Fl., p. 76, PI, x, Fig. 1 ; Haydeii's Auii. Uept., 187G, p. 482. 



