COAL PLANTS. lOI 



tender bodies are as little suited as those of aU other 

 mosses for being preserved 'in a fossil state, palaeontology 

 can give us no information about this. 



We learn from the science of petrifactions much more 

 than we do in the case of Mosses of the importance which 

 the second branch of Prothallus plants — that is, Ferns — 

 have had in the history of the vegetable world. Ferns, or 

 more strictly speaking, the "plants of the fern tribe" 

 (Filicinese, or Pteridese, also called Pteridophyta, or Vascular 

 Cryptogams), formed during an extremely long period, 

 namely, during the whole primary or palaeolithic period, the 

 principal portion of the vegetable world, so that we may 

 without hesitation call it the era of Fern Forests. From the 

 beginning of the Devonian period, in which organisms 

 living on land appeared for the first time, namely, during 

 the deposits of the Devonian, Carboniferous, and Permian 

 strata, plants like Ferns predominated so much over all 

 others, that we are justified in giving this name to that 

 period. In the stratifications just mentioned, but above all, 

 in the immense layers of coal of the Carboniferous or coal 

 period, we find such numerous and occasionally weU pre- 

 served remains of Ferns, that we can form a tolerable vivid 

 picture of the very pecuKar land flora of the palaeolithic 

 period. In the year 1855 the total number of the then 

 known palaeolithic species of plants amounted to about a 

 thousand, and among these there were no less than 872 Ferns. 

 Among the remaining 128 species were 77 Gymnosperms 

 (pines and palm-ferns), 40 Thallus plants (mostl}^ Alg^e), and 

 about 20 not accurately definable Cormophyta (stem-plants). 



As already remarked. Ferns probably developed out of the 

 lower liverworts in the beginning of the primary period. 



