rOSSlL FLORA. 671 



Dryopteris xantholithense n. sp. 



n. LXXXI, lig. 1. 



Frond pinnate?; pinnre lanceolate; pinnules o^jposite, lanceolate-deltoid, 

 obtuse, cut to within one-third of their length of the base, much arched 

 upward at the point; nervation simple, consisting of well-marked midvein 

 and 9 or 10 pairs of opposite, parallel, unbranched lateral veins; sori large, 

 round, on the backs of the veins at about one-third of their length from 



the midvein. 



Of this well-marked species the single specimen figured was the only 

 one found. It is not preserved entire, the fragment being about 5 cm. in 

 length. There is therefore no means of knowing whether or not it was 

 simple or compound. The i)ortions of tlie pinnre preserved are of the same 

 width throughout, showing that they pmbably came from the middle por- 

 tion. The pinnules are opposite and arise at an angle of 30° or 40'^ from 

 the rachis. They are lanceolate-deltoid in shape, and about 12 mm. long 

 and 5 nun. broad, l)eing much arched upward at the extremity. The fruit 

 dots are large, round, and placed on the backs of the veins near the mid- 

 vein. 



This species is allied to Dryopteris tveedii, from which it clearly differs 

 in having much shorter, arching phmules, only 9 or 10 pairs of nerves, and 

 larger fruit dots which are nearer the midvein. The nervation is the same 

 in character, but differs, as stated, in number of pairs of veins. 



From Lastrea gohlkma this species differs in much the same manner. 

 It has more arching pinnules, and is quite different in general appearance. 

 The number of pairs of nerves is, however, about the same; all of which 

 goes to show that these three species are closely related. 



Habitat: Fossil Forest Ridge, Yellowstone National Park, bed No. 6, 

 "Platanus bed;" collected by Lester F. Ward and F. H. Knowltou, August 

 19, 1887. 



DeVAI.LIa! MONTANA U. Sp. 



PL LXXIX, fig. 4. 



Frond thin, twice pinnate, possibly more compounded; rachis strong; 

 pmnjB alternate, lanceolate, ending in a sharp, hair-like point; cut into 5 



