﻿1 8 SCOTT, Early History of Seed-bearing Plants. 



we have not yet been able to follow this ancient line of 

 seed-plants to its origin. The ancestors of the Pterido- 

 spermeae are still unknown, and may have differed in 

 important respects from ferns as we now understand 

 them. What we are entitled to say, on present evidence, 

 is that the most primitive seed- plants known to us 

 present close affinities with the ferns, and must have 

 sprung, with them, from a common stock, while they show 

 no indication of any near relationship to the other 

 families of Pteridophyta. 



It now remains for us to consider whether this con- 

 clusion may be extended to other groups of Palaeozoic 

 seed-plants. 



Since the researches of Grand 'Eury ('77) and Renault 

 ('79), nearly 30 years back, it has been known that the 

 characteristic Gymnosperms of Palaeozoic times were not, 

 as had been previously supposed, Coniferae, but belonged 

 to a distinct family, that of the Cordaiteae. The work 

 which had been begun by Carruthers and Williamson was 

 carried on with such brilliant success by the French in- 

 vestigators that we have been placed in possession of 

 wonderfully complete data as to all the organs in certain 

 plants of this group. The habit of the trees, the form of 

 their leaves, the minute structure of leaf, stem, and root, 

 the characters, both external and internal, of the male and 

 female inflorescences, and the structure of the seeds have 

 all been revealed. We have only to regret that the best of 

 the available material seems to have been soon exhausted, 

 and that our knowledge of the family has not been widened, 

 to the extent we might have hoped for, by later researches. 



The Cordaiteae were lofty trees, with a tall erect shaft, 

 terminating in a crown of branches bearing large, simple 

 leaves, sometimes a yard or more in length. Some of the 

 Conifers of the Southern Hemisphere, especially the large- 



