44 



ANCIENT PLANTS 



dence alone, we should be in almost complete ignorance 

 of the earliest types of vegetation and all the simpler 

 cohorts of plants, because their minute size and very 

 delicate structure have always rendered them unsuitable 

 for preservation in stone. At the same time, had we 

 none of the knowledge of the numerous fossil forms 

 which we now possess, there would be great gaps in 

 the series which no study of living forms could supply. 

 It is only by a study and comparison of both living and 

 fossil plants of all kinds and from beds of all ages that 

 we can get any true conception of the whole scheme of 

 plant life. 



Grouping together all the main families of plants 

 at present known to us to exist or to have existed, we 

 get the following series: 



Thallophyta . 

 Bryophyta 



Pteridophyta . 

 Pteridospermae 



Gymnosperms . 

 Angiosperms 



Group. 

 /Algae 



t Fungi 



f Hepaticae 



(Musci 



fEquisetales 



J Sphenophyllales ' 



Lycopodales 



Filicales 



Lyginodendrae * 

 'Cycadales 



Bennettitales * 



Ginkgoales 



Cordaitales * 



Coniferales 

 ^Gnetales 

 ( Monocotyledons 

 \ Dicotyledons 



Common examples of typical 

 families in the group. 



Seaweeds. 



Moulds and toadstools. 



Liverworts. 



Mosses. 



Horsetails. 



fossil only, Sphenophylhim. 



Club-moss. 



Bracken fern. 



fossil only, Sphenopteris. 



Cycads. 



fossil only. Binnettites. 



Maidenhair Tree. 



fossil only, Cordaites. 



Pine, Yew. 



Welwitschia. 



Lily, Palm, Grass. 



Rose, Oak, Daisy. 



In this table the different groups have not a strictly 

 -equivalent scientific value, but each of those in the 

 second column represents a large and well-defined 

 series of primary importance, whose members could 

 not possibly be included along with any of the other 

 groups. 



Those marked with an asterisk are known only as 



