PALEOBOTANY BERRY. 



38' 



evolution had accomplished much. Moreover, there were special 

 stimuli to change in the wide extent of continental areas, the forma- 

 tion of mountain ranges, the diversification of climates, and the 

 competition of new plant associations that had resulted from the 

 Permian glaciation. Furthermore, many geologists consider the 

 prevailingly red deposits of the Triassic indicative of extremely 

 arid if not real desert conditions. Without subscribing to this ex- 

 treme view, it is probable from the geography of that time alone 

 that the climates were less humid or uniform than they had been 

 previous to the Permian glacia- 

 tion; at least such was the case 

 during the earlier Triassic. 



Marine Triassic deposits of 

 the Mediterranean regions at- 

 test to the abundance of cal- 

 careous algae (Diplopora, Gy- 

 roporella) at that time. On 

 the land, mosses and hepatics 

 were unknown and the floras 

 consist overwhelmingly of ferns, 

 Cycadophtes and Conifers, 

 Among the ferns most of the 

 Paleozoic types are missing or 

 much reduced. The whole class 

 Coenopteridae or Primofilices 

 was absent. The class Hydrop- 

 teridae, never abundant in the 

 geological record, was sparingly 

 represented in the late Triassic 

 by Sagenopteris. The Euspo- 

 rangiate ferns, so common in 

 the Carboniferous and Permian, 

 where they were represented by 

 Psaronius, Pecopteris, etc., were 

 the most prominent fern element during the Triassic, with seven or 

 eight genera and a large number of species, especially in the Keuper 

 and Rhaetian (Danaeopsis, Taeniopteris, Macrotaeniopteris, Maratti- 

 opsis, Angiopteridium, Pseudodanaeopsis, Asterotheca, Oligocarpia). 

 Macrotaeniopteris with its large strict simple fronds was especially 

 common in the rocks of the Newark formation in the eastern United 

 States. The Leptosporangiate ferns, which comprise the bulk of the 

 living ferns, were represented in the Triassic by the more ancient 

 families, Gleicheniaceae, Osmundaceae, Dipteriaceae, and Matonia- 

 ceae, while Cheiropteris of the late Triassic is thought to represent 

 the Ophioglossales. 



Fig. 31. 



■Restoration of Macrotaeniopteris (after 

 Russell), X 1/10. 



