[Chap. Lll 



PLANTS OF THE PAST 



729 



362 ) . These were the first seed plants and they seem to have developed 

 from the same ancestral stock as the true ferns. Thev reached their 







Fig. 362. A seed tern (Eospermatopteris) of the Devonian period. Restoration by 

 W. Goldring. Courtesy New York State Museum, Albany. 



greatest development in the late Paleozoic, and along with the primitive 

 lycopods soon after became extinct. From the Devonian onwards primi- 

 tive gymnosperms were associated with them, for example, Cordaites 

 (Fig. 363). 



The luxuriant vegetation of the Carboniferous seems to indicate a 

 warm temperate, moist climate with a very narrow range of variation 

 of temperature. Trees and woody plants seem to have been predomi- 

 nant; the properties of coal strata are due to the woody character of the 

 parent materials. These coal strata, however, contain occasional layers 

 rich in spores, and layers that are possibly of algal origin. 



The Permian rocks indicate a period of extreme aridity, and also of 

 glaciation, which can be accounted for by the great crustal changes 

 that occurred at the close of the Paleozoic Era. Both of these climatic 

 changes probably contributed to the destruction of the Carboniferous 

 floras. 



No fossil flowering plants ( angiospemis ) have been found in Pa- 

 leozoic rocks. The evolution of sepals, petals, pistils, fruits, fusion nuclei, 



