170 THE FLORA OF THE DAKOTA GROUl'. 



base to a sliort petiole; secondaries consisting of ten to twelve pairs diverg- 

 ing at an angle of 50° to 55° from the midrib, a little cnrving in trav- 

 ersing the blade, arched along and near the borders without osculating in 

 festoons. 



I have no point of comparison for these leaves. The nervation is much 

 like that of /?. tenax Lesq., but the leaves have a far different aspect and 

 the angle of divergence of the secondaries is twice as broad. 



Habitat: Ellsworth County, Kansas. Nos. 793 and 794 of the museum 

 of the University of Kansas; E. P. West, collector. 



Ehamnus tenax Lesq. 

 PI. XXXVIII, Fig, 6. 

 Orc't. Fl., p. 109, PI. XXI, Fig. 4. 



The leaf is merely a little smaller than B. Mudgei described above, but 

 identical in all the characters. 



Habitat: Ellsworth County, Kansas. No. 791 of the museum of the 

 University of Kansas; E. P. West, collector. 



Rhamnvs iN-a:QuiLATERAXis, sp. nov. 

 PI. XXXVII, Figs. 4-7. 



Leaves subcoriaceous, entire, broadly or narrowl}^ lanceolate, acumi- 

 nate, nan-owed and decurring to a sliort petiole, inequilateral, curved to one 

 .side or subfalcate; primary nerves narrow; secondaries at an acute angle 

 of divergence, camptodi-ome. 



These leaves, though related to the following species, especially in 

 their nervation, are more variable in length, being from 3.5*"" to 8"'" long, 

 and from 1"" to 3.5°'" broad, tapering- u}) to an acumen, attenuated to the 

 base in the same degree and slightly decurrent in reaching the petiole. 

 The secondaries, diverging at an angle of 20° to 25°, curve near the borders, 

 following them in anastomosing in a simple or double series of areoles; the 

 lowest pair being thin and marginal. 



It is related to the following species, from which it is, however, distinct 

 by the form of the leaves and the nervation. It has also a marked degree 

 of affinity to B. (I'lihif/oisis A\. Br., as it is represented in Heer's Fl. Tert. 

 Helv. (vol. 3, p. 78, PI. cxxiii. Fig. 31), at least by the form of the mequi- 

 lateral leaves and the acute divergence of the secondaries, which, however, 

 are more ramose in tlie Cretaceous sj)ecies. Its relation to Ficiis jtriiiKirdi- 



