512 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. 41. 



migration of this land plant element was very probably by the north 

 Pacific. 



The most important deduction to be drawn from the occurrence 

 of Gigantopteris and its particular associates in North America is 

 the essential continuity of environmental conditions indicated 

 thereby. The vital conditions under which the types lived in Okla- 

 homa and Texas can not have been very far different in their essential 

 respects from those prevaihng in the Chinese habitats of the types. 

 Environmental conditions sufficiently uniform to enable these plants 

 to thrive must have attended the route of their land migration. We 

 may therefore conclude that a climatic environment essentially 

 similar extended from China to western North America ; that is, that 

 during Giganto'pteris time western North America and portions of 

 eastern Asia were probably included in the same chmatic province. 

 The minghng of the western European flora with the Chinese ele- 

 ments in Oklahoma and Texas suggests that the latter region may 

 have been on the eastern border of the provmce. 



Another interesting feature of the western Permian is the presence 

 of fronds possibly identical with Psygmopliyllum cuneifolium, Odon- 

 topteris permiensis, Odontopteris jischeri, and SplienopJiyllum stouken- 

 hergi, species that seem not to have been known outside of the Uralian 

 region, from which they were described. Possibly the remarkable 

 Kansas tj^pe described by Sellards ^ as Glenopteris, which is unlike 

 any European type of its period, and which may be nearest related 

 to the Neuropteris salicifoUa of Morris, also is of Uralian or Asiatic 

 descent. The types of Uralian origin also may have reached western 

 North America by the north Pacific route. 



According to their composition and relations the floras of the 

 younger Carboniferous in Shansi and Sheng-King, or Manchuria, 

 which are either at the latest Pennsylvanian stage or in the early 

 Permian, may with probable safety be assumed to have antedated the 

 early Gondwana glaciation and the existence of the Gangamopteris 

 flora in southern Asia. The question arises, then, whether the floral 

 peculiarities of the Gigantopteris province are due in part to climatic 

 changes leading to refrigeration in India, and whether later the 

 cUmate of the Gangamopteris province extended over a portion at 

 least of the Gigantopteris province, and if so, whether it did not cover 

 a part of western North America. 



CONCLUSIONS. 



The genus Gigantopteris Schenck, common in the Permian "Red 

 Beds" of Texas and Oklahoma, is a plant with large sympodially(?) 

 dichotomous pinnae, and confluent (and thus elongately meshed) 

 Goniopteroid nervation. It is in many respects strongly suggestive 



> Kans. Univ. Quar., vol. 9, 1900, p. 179. 



