PALAEONTOLOGY 65 



the Calamites. Tlieir modern representatives are the 

 Equisetums or Mares' tails, which are often very numer- 

 ous in the places where they grow at all, and which are 

 represented by species adapted to life in dry ground 

 and others that inhabit shallow water. The English 

 species do not exceed a few feet in height, but there 

 are some foreign ones that grow in groves together 

 and thus help to support each other's slender shafts to 

 a height of twenty or more feet. These plants must 

 represent on a somewhat smaller scale much of the 

 external appearance that was probably presented by 

 their sturdier and more complex ancestors. 



One other family from the coal flora must be men- 

 tioned and this is one that has now no relative still 

 living. Its existence would never have been suspected 

 had we not had detailed knowledge of the fossils. This 

 group was recently discovered, or rather recognised, 

 and named by Professor Oliver and Dr. Scott the 

 Pteridospermse. Its name indicates the nature of the 

 group, for it means Pteridophytes, that is fern-like 

 plants bearing seeds. Among modern plants seeds 

 are only borne by the higher families the Gymno- 

 sperms and the Angiosperms, ferns and all the tribes 

 below them having nothing more advanced than spores. 

 Hence this ancient group which connects the fern-like 

 plants with those which bear seeds is a most important 

 link in the chain of evolution of the vegetable world. 

 There are many side issues of interest connected with 

 the recent discoveries of these fossil forms, and one of 

 these is the stress it has laid anew on the dictum which 

 all know and all ignore, viz., that appearances are 

 deceitful. One of the most generally accepted tenets 

 about the flora of the past in Coal Measure times had 

 been that it was the " Age of Ferns," because there 



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