212 The Palaeo7itological Record. II. Plants 



far more advanced than the Pteridospermeae, and in many respects 

 approaching the Coniferae, which themselves begin to appear in the 

 latest Palaeozoic rocks. The Cordaiteae, while wholly different in 

 habit from the contemporary fern-like Seed-plants, show unmis- 

 takable signs of a common origin M'ith them. Not only is there 

 a whole series of forms connecting the anatomical structure of the 

 Cordaiteae with that of the Lyginodendi'eae among Pteridosperms, 

 but a still more important point is that the seeds of tlie Cordaiteae, 

 which have long been known, are of the same Cycadean type as those 

 of the Pteridosperms, so that it is not always possible, as yet, to 

 discriminate between the seeds of the two groups. These facts 

 indicate that the same fern-like stock which gave rise to the Cycado- 

 phyta and through them, as appears probable, to the Angiosperms, 

 was also the source of the Cordaiteae, which in their turn show 

 manifest affinity with some at least of the Coniferae. Unless the 

 latter are an artificial group, a view which does not commend itself 

 to the writer, it would appear probable that the Gymnosperms 

 generally, as well as the Angiosperms, were derived from an ancient 

 race of Cryptogams, most nearly related to the Ferns ^ 



It may be mentioned here that the small gymnospermous 

 group Gnetales (including the extraordinary West African plant 

 Welwitschia) which were formerly regarded by some authorities 

 as akin to the Equisetales, have recently been referred, on better 

 grounds, to a common origin with the Angiosperms, from the 

 Mesozoic Cycadophyta. 



The tendency, therefore, of modern work on the palaeontological 

 record of the Seed-plants has been to exalt the importance of the 

 Fern-phylum, Avhich, on present evidence, appears to be that from 

 which the great majority, possibly the whole, of the Spermophyta 

 have been derived. 



One word of caution, however, is necessary. The Seed-plants 

 are of enormous antiquity ; both the Pteridosperms and the more 

 highly organised family Cordaiteae, go back as far in geological 

 history (namely to the Devonian) as the Ferns themselves or any 

 other Vascular Cryptogams. It must therefore be understood that 

 in speaking of the derivation of the Spermophyta from the Fern- 

 phylum, we refer to that phylum at a very early stage, probably 

 earlier than the most ancient period to which our record of land- 

 plants extends. The affniity between the oldest Seed-plants and the 

 Ferns, in the widest sense, seems established, but the connnon stock 

 from which they actually arose is still unknoAvn ; though no doubt 



^ Some botanists, however, believe that the Coniferae, or some of them, are probably 

 more nearly related to the Lycopods. See Seward and Ford, "The Araucarieae, Recent 

 and Extinct," Phil. Trans. Royal Soc. Vol. 198, b. 1906. 



