EVOLUTION OF SEED-PLANTS 115 



this group has completely transformed our old 

 ideas of the Palaeozoic Flora. Most of the Ferns, 

 so-called, were not Ferns at all, but seed-bearing 

 plants, and hence the Palaeozoic period can no 

 longer be called the "Age of Cryptogams," in 

 the sense that Cryptogams were then really 

 dominant. The Seed-plants already held their 

 own very well, and probably may have about 

 equalled the Spore-plants in number of species. 



What conclusion are we to draw from the 

 presence, in Palaeozoic times, of the vast group 

 of Fern-like but seed-bearing plants which we 

 call the Pteridosperms? It is not for nothing 

 that they have been called Ferns for so long. 

 The resemblance to Ferns is not only external 

 the two groups have many points of structure 

 likewise in common, and, as regards the pollen- 

 bearing organs, it is still almost impossible to 

 distinguish between the pollen-sacs of a Pterido- 

 sperm and the sporangia of a true Fern. Both 

 seeds and male organs appear to have been borne 

 on almost unaltered foliage-leaves, an altogether 

 Fern-like arrangement. 



On the other hand, the characters allying the 

 Pteridosperms to Cycadophyta are no less clear. 

 There are many points of close agreement in 

 the anatomy, so close as to have been quite 

 enough to establish relationship before anything 

 was known of the organs of reproduction. An 



