558 PROCEEDINGS OF THE NATIONAL BIVSEVM. vol.45. 



pairs of alternate remote pinnules. The terminal leafy branches 

 (pinnse) exceeded 6 cm. in length. The pinnules range in length from 

 about 1 to 2.5 cm.; their width is between 2 and 3 mm. The pinnules 

 were clearly coriaceous in texture, as they appear thick and rigid, and 

 have the margins distinctly revolute. 



The presence of sori in these specimens is more or less in doubt, there 

 being only a number of minute dots or pits, usually about two in each 

 segment, that may represent very immature fruit. Their relation to 

 the veins can not be certainly ascertained. 



The Hving representatives of the Gleicheniaceae, upward of 100 in 

 nimiber, according to American students, are comprised in four genera, 

 two of which (Platyzoma and Stromatopteris) are monoty]Dic. The 

 other species are distributed among Gleichenia proper and Dicranop- 

 teris, the latter covering the ground of the former section Mertensia} 

 These are distinguished mainly as follows : In Dicranopteris the veins 

 are free, once or several times forked, and the sori dorsal on the 

 veins, while in Glechenia the veins are simple and the sori terminal 

 on the veins. According to Underwood,^ followed by Maxon,^ who 

 has recently monographed the American forms, the genus Gleichenia 

 as now restricted is not found in the New World, all being referable 

 to Dicranopteris. It is believed that the fossil form under consider- 

 ation, belongs, so far as the essential features can be made out, to 

 Gleichenia. If this is correct, and it is thought to be, it is of interest 

 as showing that in the late Cretaceous time the genus Gleichenia was 

 an inhabitant of America, and many hundreds of miles north of the 

 present habitat of any living representative of the family. 



In many cases the absence of fructification in fossil ferns makes 

 then classification more or less a matter of question, but with the 

 present specimens there can hardly be the possibiUty of error. The 

 manner of forking, the included terminal bud and the coriaceous, 

 narrow, moniliform pinnules with revolute margins, are so exactly 

 the characters of Gleichenia that there can be no reasonable question. 

 It is, for instance, very much like the Australian G. circinata Swartz, 

 which is itself apparently a variable species. 



Among fossil species referred to Gleichenia the present one is perhaps 

 closest to several described by Heer * from the Kome (Lower Cretace- 

 ous) of Greenland. It has the same habit as G. zippei Heer, but is 

 much smaller. It is nearest to G. gracilis Heer and to G. delicatula 

 Heer, but differs in regard to the lobation and shape of the jjinnules. 



1 Mertensia is preoccupied by the Boraginaceous genus of this name. 



2 BuU. Terr. Bot. Club, vol. 34, 1907, pp. 243-262. 



3 North Amer. Flora, vol. 16, pt. 1, 1909, pp. 53-63. 



* Flora Foss. Arct., vol. 3 (Kreide-flora d. Arct. zone), 1S74, pis. 3-11. 



