Maryland Geological Survey 2-il 



the assertion that some at least of the fronds described under this name 

 are those of Osmundacese." ' Zeiller "" has recently described a species 

 from the Wealden of Peru, which he considers identical with or very 

 close to Gladophlehis Browniana, in which the sporangia are biseriate, 

 oval, and annulate as in the Schizaeacese. These are said to be very 

 like those of the Jurassic genus Kluhia of Eaciborski. In the Potomac 

 flora we find that fourteen so-called species of Aspidium Swartz (Dnj- 

 opteris Adanson), mostly fertile fronds, were described by Fontaine in 

 1890. These showed mostly large elliptical or reniform sori in rows on 

 each side of the midvein, and located generally on the distal branch of 

 a furcate vein, usually wanting in the apical part of the pinnule. These 

 were compared by this author with modem species of Aspidium, Cys- 

 topteris, Folystichum, and Didymochlcena. The preservation is not of 

 the best, the matrix being coarse, and Fontaine's figures are largely 

 idealized. It has seemed remarkable that the fronds of Dryopteris in 

 the Potomac beds were almost always fertile, while those of Gladophlehis 

 in intimate association with them were invariably sterile. 



By careful comparison it has been possible to correlate the fertile 

 specimens described as Dryopteris with the sterile Gladophlehis fronds 

 of the same species in five of the types .which are represented in the 

 Potomac flora by sterile and fertile fronds, and the presumption is 

 strong, although unverified, that the remaining Dryopteris forms repre- 

 sent fertile fronds of Gladophlehis, although they are set apart in the 

 present publication in the genus Dryopterites. While the foregoing facts 

 are not in unison in regard to the systematic position of Gladophlehis 

 they all point to the inclusion of the following American species in the 

 family Polypodiacese, or what answered to this family in Lower Cre- 

 taceous times, and cast some doubt upon Raciborski's suggestion that 

 Gladophlehis denticulata and other species of the same genus were the 

 sterile fronds of Osmundaceous ferns. It is quite possible that ferns 

 of more than one subfamily of the Polypodiacege, or, indeed, of other 

 families, are included among the various described species of Gladophle- 



^ Seward, Fossil Plants, vol. il, 1910, p. 345. 

 ^ Zeiller, Comptes rendus, tome cl, 1910, p. 1488. 



