24 THE FLORA OF THE DAKOTA GROUP. 



FILICES, FERNS. 

 Family POLYPODIACE^. 

 Tribe PECOPTERIDE>E. 



Pecopteris nebbaskana Heer. 



Saporta, Fl. Foss. de Suzanne, p. 332, Fig. 8; Lesquereux, Cret. Fl., p. 46, PI. xxix, 



Figs. 5, 5a. 



Tribe PTERIDE^^. 



Pteris dakotensis, sp. nov. 

 PI. I, Figs. 2, 3. 



Ultimate piiinse linear-lapceolate, pinnately deeply cut into oblique 

 equal subopposite lanceolate blunt-pointed and subfalcate pinnules, con- 

 nate above the base, entire, close but disconnected above ; median nerve 

 thin, distinct ; secondaries opposite, 6-7 pairs, simple, curving upAvard in 

 passing to the borders. 



This species is comparable, at least in the form and the disposition of 

 the pinnules, to P. Albertsii Dunk., as figured by Heer.^ It is, however, 

 smaller in all its pai-ts ; the pinnules are clearly disconnected from below 

 the middle, and the lateral veins simple. 



Habitat: Ten miles northeast of Delphos, Kansas. No. 4048 of Mr. 

 R. D. Lacoe's collection, of Pittston, Pennsylvania. 



Tribe ASPLENIEvE. 



AsPLENiuM DiCKSONiANUM Heer. 

 PI. I, Figs. 1, la. 



Heer, Fl. Foss. Arct., vol. 3, pt. 2, p. 31, PI. i, Figs. 1-5 ; vol. 6, 2 Abth., p. 3, PI. ii, 

 Figs. 2, 2b; p. 33, PI. xxxil, Figs. 1-8. 



"Leaves triply pinnate; rachis firm, rigid; primary and secondary 

 pinnae lanceolate ; ])innules narrowly lanceolate, the lower acute serrate, 

 the upper entire, acute." 



iPl. Fos8. Arct., vol. 6, 2 Abth., p. 29, PI. xxviii, Figs. 1-3. 



