No. 2388. TERTIARY FOSSIL PLANTS FROM VENEZUELA— BERRY. 559 



Phylum PTERIDOPHYTA. 

 Class LEPTOSPORANGIATAE. 



Order POLYPODIALES. 

 Family POLYPODIACEAE. 



Genus BLECHNUM Linnaeus. 



BLECHNUM BETUOQUENSIS, new species. 



Plate 107, fig. 1. 



Fronds of medium size, pinnate. Pinnae ovate-lanceolate, with an 

 acuminate apex and a rounded base. Midvein stout, prominent. 

 Lateral veins numerous, closely spaced, parallel, simple or once 

 forked, craspedodrome, diverging from the midvein at wide angles 

 and curving gently upward. Margins, except in the basal region, 

 with small crenate-serrate teeth. No traces of sori or fertile pinnae. 



This species, which is clearly new, is represented by a considerable 

 amount of broken material, which is sufficient, however, to show the 

 pinnate character of the frond and all of the details of the sterile 

 pinnae. In the absence of fruiting characters its generic reference 

 is beset with difficulties, since it resembles a number of existing 

 tropical American forms which have been variously assigned to the 

 genera Blechnum, Lomariopsis, Stenochlaena, etc., by students of 

 living ferns. 



The genus Gymnogramme has a Neuropteroid instead of a Taeniop- 

 teroid venation, which eliminates it from consideration. On the 

 whole it has seemed best to refer the present species to the genus 

 Blechnum, although the generic limits of this and other tropical fern 

 genera are variously interpreted by different authorities and are 

 evidently not clearly understood. The genus has a large number of 

 mostly tropical species, and is well represented at the present time 

 in northern South America. The present species may be compared 

 with Blechnum serrulatum Richards, Blechnum hrasiliense Desveaux, 

 and other members of the genus to be found in the rain forest country 

 from Central America to Brazil and Bolivia, all of which show a 

 general similarity to the fossil species. 



Collected from light colored clay interbedded with sandstone, 

 exposed on a small hill on the northeastern outskirts of the town 

 of Betijoque. 



Holotype.—C&t. No. 36423, U.S.N.M. 



