INTRODUCTION 7 



upon the muddy bank of some ancient pond or marsh, we can 

 never know, as we can hardly hope to find recognizable remains 

 of the extremely delicate and perishable organisms of the very 

 ancient formations when land life first began. 



Fungi 



In addition to the algae, which are characterized by the pi 

 ence of the characteristic green pigment, chlorophyll, there is a 

 vast assemblage of plants, structurally of about the same degree of 

 development as the algae, and perhaps derived from them. Th< 

 plants, the fungi, are destitute of chlorophyll, and hence depend- 

 ent on organic substances for food, and at the present time play 

 a very important role in the land-vegetation of the woild. 



While there is abundant evidence that fungi existed in the 

 earlier geological formations, the record is too incomplete to 

 throw much light on their early history. The best known fossils 

 are parasitic forms which are found in the tissues of higher plants, 

 and it is evident that as at present fungi were the cause of serious 

 plant diseases. 



The First Land Plants 



The first unmistakable land plants are first met with in the 

 early Devonian formations, but these have already attained a 

 structure which implies a long series of intermediate forms be- 

 tween them and the ancestral algae. 



The Bryophytes (mosses and liverworts), which are the low 

 of the existing land plants, have apparently left few recognizable 

 traces in the ancient rocks. There is every reason to believe that 

 these have existed for a period antedating the first known remaina 

 of land plants, but their delicate tissues are extremely perishable 

 and positive evidence is not at present forthcoming. These plants 

 have been rather neglected by the students of fossil plants, and 

 possibly a more intensive search for their remains may throw light 

 upon their early history. 1 



The early Devonian land plants belonged bo a peculiar group 

 of vascular plants, i. e., plants with woody conducting tissues— 



1 A paper by Mr. J. Walton, in the Annuls of Botany, July, L926, describe! 

 liverworts from shales belonging to the Middle Coai-Meaflure Age, from Shropal 



in England. 



