DESCRIPTION OF SPECIES— FILICES. 53 



would be a terminal pinna. It seems, therefore, that these fragments are 

 mere leaflets. They are in size from eight to ten centimeters long, and from 

 one and a half to three centimeters broad, wilh a narrow midrib, and thick, 

 distinct veins, all under the same angle of divergence, 60°, simple or forking 

 once, and reaching the bordei's straight, or without deflecting upward or down- 

 ward. The borders, by contraction at the point of connection of the veins, 

 are sliglitly crenulate. This character is unlike that of the nervation of 

 Osmumla leaves, to which this Fern might be compared, by the form of the 

 leaflets, resembling those of plate iv, fig. 1. Taken for simple fronds, they 

 have a relation to Acrostichum latifolium, Sw., var. aLlsirKzfolium of Cuba, 

 which has the same type of nervation. As leaflets of a compound frond, they 

 are comparable io Acrostichum cervhmm, Sw., or Lomariopsis Wrightii, Mett., 

 both Cuban species also. 



Habitat. — Golden, Colorado. 



Pteris erosa, Lesqx. 



Plate IV, Fig. 8. 



Ptei-is erosa, Lesqx., Supplement to Annual Report, 1871, p. 12 ; Annual Eeport, 1873, p. 392. 



Pinnae large, broadly lanceolate, taper-pointed ; border obtusely dentate toward the point, irreg- 

 ularly crenulate-lacerale in the middle ; middle nerve thick ; veins at an open angle of divergence, fork- 

 ing once or twice, slightly turued up iu reaching the borders. 



The only specimen of this Fern figured here represents the point of a 

 large pinna, the fragment being five and a half centimeters long and three 

 centimeters broad toward the middle. The pinnse are near the point regu- 

 ularly obtusely dentate ; but lower the teeth become irregular in form and 

 size, and more or le.ss deeply eroded. The veins are about at the same angle 

 of divergence as in the former species, to which this one has a close relation ; 

 they differ, however, by more numerous divisions, and especially by their dis- 

 position to slightly curve up in reaching the borders. By this character, the 

 siiecies is allied to Fteris j)arschlugiana, Heer, Bornst. FI., p. 7, pi. 1, fig. 1, 

 which has the veins divided about in the same way. 



Lately, after the printing of the plate and the preparation of the descrip- 

 tion, I have received from Rev. A. Laken, and found at Golden, a splendid 

 specimen, with- one leaflet preserved in its integrity. It is seventeen centi- 

 meters long, three and a half centimeters broad below the middle, linear-oblong, 

 rapidly narrowed near the point to an acumen, sharply, nearly equally dentate 

 from a little above the base, which is unecpiilateral, rounded on one side, 

 cuneate on the other, broken near the point of attachment, where it is narrowed 



