LECTURE XII 



THE PTERIDOSPERMS AND THE SEED 



" THERE is no part of Fossil Botany in which there have 

 been such revolutionary changes within a very short 

 period as in the question of the position of Palaeozoic Ferns. 

 Till within the last three years [as from 1906] the Ferns 

 were universally regarded as forming one of the dominant 

 classes of Palaeozoic plants in fact, the most dominant 

 of all and this estimate of their importance will be found 

 in all the Text-books. According to the computations 

 of systematists the Ferns constituted almost exactly 

 one-half of the known Carboniferous flora. The position 

 has now so completely changed that Professor Zeiller, 

 than whom there is no higher authority, wrote, in August 

 of last year [1905], that the Ferns of the Palaeozoic 

 period, though ' they were probably not entirely absent, 

 occupied an altogether subordinate rank.' The ground 

 for the radical change of view which Professor Zeiller's 

 words indicate, is, of course, to be found in the recognition 

 of the Pteridosperms, a class of seed-bearing plants, to 

 which, as it now appears, the great majority of the 

 supposed Palaeozoic Ferns belonged." 



In these words Dr. Scott introduces to us a sketch of 

 the remarkable discoveries that have been made of late 

 years relating to the origin of seed-bearing plants. If 

 we are to look for the point of origin of the Spermatophyta 

 away deep down in the Palaeozoic strata, then our 

 notions as to the antiquity of that phylum must be 

 radically altered, and for that reason the discoveries I 



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