EVOLUTION OF SEED-PLANTS 103 



like plants, the association between particular 

 fronds and particular seeds is constant. In 

 fact, all the evidence we have (though direct 

 proof is only afforded in a few cases) tends to 

 prove that most of the Palaeozoic plants which 

 used to be classed as Ferns were hi reality seed- 

 bearing plants and not Cryptogams at all. Just 

 as the Cycads of the Mesozoic have turned out, 

 for the most part, to be much more advanced 

 than recent Cycads, and very near the true 

 Flowering Plants, so have the supposed Ferns 

 of the Palaeozoic proved for the most part to be 

 far superior in organisation to the true Ferns 

 and to have a real kinship with the Seed-plants. 



What then were the affinities of these "seed- 

 bearing Ferns" which formed so great a part 

 of the Palaeozoic vegetation? What was their 

 relation to the Mesozoic Seed-plants on the 

 one hand, and to the Ferns, which they so closely 

 resembled, on the other? The discovery of a 

 new and extensive class of Palaeozoic seed-bearing 

 plants may be expected to throw fresh light on 

 the evolution of the higher groups. 



We will begin by describing one particular 

 type of seed-bearing Fern, and will choose Lygi- 

 nodendron oldhamium (fig. 12), the first of these 

 plants in which the seed was identified, and now 

 the most completely known, as it happens, of 

 all fossil plants. The piecing together of all the 



