26 HOW TO KNOW THE FERNS 



there are perhaps not more than about a dozen 

 species, the sole survivors of a race which at one 

 time dominated the world. There seems every 

 reason for thinking that the Flowering Plants 

 arose as an offshoot of the Bennettiteae, and in 

 some way secured an advantage which enabled 

 them to arrive at their present position. 



When we come to consider the past history of 

 the Club Mosses the record is of a different nature 

 to that of the Ferns. Nowadays the Club Mosses 

 are not of great importance in the world, even 

 though, as will be shown later, the number of 

 species is considerable. But when we travel 

 back to Palaeozoic times, particularly in the coal 

 period, it is evident that these plants were 

 represented by a number of very large and 

 dominant families. Some of these early Club 

 Mosses certainly came very near to rivalling the 

 Flowering Plants. Probably the tendency of 

 the world to become drier has had something 

 to do with the decline, seeing that in all cases 

 the fertilization is carried out under water. We 

 may gather some idea of the importance of the 

 Club Mosses in Palaeozoic times from the fact 

 that in every part of the world where coal de- 

 posits have been examined great numbers of the 

 fossil remains of these plants are always dis- 

 covered. Many of these grew into large trees 

 which were a hundred or more feet in height, 

 sending out great branching shoots above and 

 an enormous root system below. 



From a botanical point of view there is no 

 doubt that some of the Club Mosses, particularly 

 those belonging to the family Selaginellacece, 

 have approached very nearly to the Flowering 

 Plants. At the present time the existing species, 

 the Selaginellas, bring us up to the very threshold 

 of the dominant group. The lowest division 



