THE DEVONIAN PERIOD. 493 



allies) and the lower gymnosperms. 1 The angiospermous flowering 

 plants were not represented, so far as known. 



The record of the lower plant groups (on the land) is almost nega- 

 tive. There is no evidence of liverworts or mosses (Bryophytes) nor 

 of terrestrial algae and fungi (Thallophytes) , except that, interestingly 

 enough, bacteria (both bacillus and micrococcus) have been reported. 2 

 The identification of such simple forms in fossilized woody tissue at 

 so ancient a period is remarkable, but the presence of bacteria is alto- 

 gether probable, for there is good reason to think that the decay of 

 vegetation was then, as now, accelerated by bacterial action. Other- 

 wise the vegetal record should be more perfect. 



The ptericlophytes were represented in nearly every division. Among 

 the Filicales there were true ferns (Filices), and apparently also forms 

 intermediate between ferns and cycads (Cycadofilices, Pteridospermce). 

 The Equisetales were represented by calamarians ; the Sphenophyllales 

 by the type genus Sphenophyllum, while the Lycopodiales were present 

 in the form of Lepidodendron and possibly Sigillaria, reported by 

 some authors but questioned by others. The spermatophytes, on 

 the other hand, seem to have been represented only by their lower 

 division, the gymnosperms, and these perhaps only by Cordaites, 

 though conifers and ginkgos have been reported. The identifications 

 are, however, questioned. 



The general aspect of the ferns was already like that of the exist- 

 ing forms, but the other families were archaic and peculiar. It is 

 not a little singular that forms seemingly so delicate as the ferns should 

 have been among the most persistent and least modified of terrestrial 

 plants. Notwithstanding their relatively modern aspect, they were 

 archaic in many features, and embraced a much wider range of characters 

 than at present. 3 The larger number were herbaceous, but tree-ferns 

 (Psaronius), not unlike those now living in the tropics, were present. 

 The ferns were already so far advanced in evolution that little has 

 yet been learned from them relative to their ancestral relations. They 

 are thought to have been the progenitors of the Cycadofilices (Pterido- 

 spermce), and through them of the cycads and of most or all the other 



1 For classification see Vol. I, p. 653. 



2 Renault, Ann. Sci. Notes, Vol. II, 1896. See also Steward, Fossil Plants, 1898, 

 pp. 133-138. 



3 D. H. Scott, Studies in Fossil Botany, p. 506. 



