THE METAMORPHOSES OF PLANTS 83 



was at first cold, but the doctrine which it enforced 

 g*radually won the attention of botanists, and by 1830 

 he was able to show that it had been accepted by many 

 g^ood judges. 



Then came the discoveries of Hofmeister, followed by 

 Darwin's Origin of Species. Naturalists soon ceased 

 to put the old questions, and the old answers did not 

 satisfy them. Wolff and Goethe had generalised the 

 flov/ering plant until it became a series of leaf-bearing 

 nodes alternating with internodes, but no such abstract 

 conception could throw light upon the common ancestor 

 of all the flowering plants, nor upon the stages by which 

 the flowering plant has been evolved, and it was these 

 which were now sought. Hofmeister brought to light 

 a fundamental identity of structure in the reproductive 

 organs of the flowering plants and the higher cryptogams. 

 There has since been no doubt in what group of plants 

 we must seek the ancestor of the flowering plant. It 

 must have been a cryptogam, not far removed from the 

 ferns, and furnished with sporophylls — i.e.^ leaf-like 

 scales, on which probably two kinds of sporangia, lodging 

 male and female spores respectively, were borne. The 

 careful investigation of the fossil plants of the coal 

 measures has brought us still nearer to the actual pro- 

 genitor. Oliver and Scott^ have pointed out that the car- 

 boniferous Lyginodendron, though showing unmistak- 

 able affinity with the ferns, bore true seeds, as a pine or 

 a cycad does. Many other plants of the coal measures 

 are known to have combined characteristics of ferns 

 with those of cycads, while some of them, like Lygino- 

 dendron, crossed the frontier, and became, though not 

 yet flowering plants, at least seed-bearers. 



The discovery of a fossil plant which makes so near 

 * Phil. Trans. ^ 1904. 



4 



