202 The Palaeontological Record. 11. Plants 



we know nothing of the origin of life ; consequently, for all we 

 can tell, it is as probable that life began, on this planet, with 

 many living things, as with one. If the first organic beings were 

 many, they may have been heterogeneous, or at least exposed to 

 different conditions, from their origin ; in either case there would 

 have been a number of distinct series from the beginning, and if so 

 we should not be justified in assuming that all organisms are related 

 to one another. There may conceivably be several of the original 

 lines of descent still surviving, or represented among extinct forms — 

 to reverse the remark of a distinguished botanist, there may be 

 several Vegetable Kingdoms ! However improbable this may sound, 

 the possibility is one to be borne in mind. 



That all vascular plants really belong to one stock seems certain, 

 and here the palaeontological record has materially strengthened the 

 case for a monophyletic history. The Bryophyta are not likely to be 

 absolutely distinct, for their sexual organs, and the stomata of the 

 Mosses strongly suggest community of descent with the higher plants ; 

 if this be so it no doubt establishes a certain presumption in favour 

 of a common origin for plants generally, for the gap between " Mosses 

 and Ferns " has been regarded as the widest in the Vegetable King- 

 dom. The direct evidence of consanguinity is however much weaker 

 when we come to the Algae, and it is conceivable (even if improbable) 

 that the higher plants may have had a distinct ancestry (now wholly 

 lost) from the beginning. The question had been raised in Darwin's 

 time, and he referred to it in these words : " No doubt it is possible, 

 as Mr G. H. Lewes has urged, that at the first commencement of life 

 many different forms were evolved ; but if so, we may conclude that 

 only a very few have left modified descendants 1 ." This question, 

 though it deserves attention, does not immediately affect the subject 

 of the palaeontological record of plants, for there can be no reasonable 

 doubt as to the interrelationship of those groups on which the record 

 at present throws light. 



The past history of plants by no means shows a regular pro- 

 gression from the simple to the complex, but often the contrary. 

 This apparent anomaly is due to two causes. 



1. The palaeobotanical record is essentially the story of the 

 successive ascendancy of a series of dominant families, each of which 

 attained its maximum, in organisation as well as in extent, and then 

 sank into comparative obscurity, giving place to other families, which 

 under new conditions were better able to take a leading place. As 

 each family ran its downward course, either its members underwent an 

 actual reduction in structure as they became relegated to herbaceous 

 or perhaps aquatic life (this may have happened with the Horsetails 



1 Origin of Species, p. 425. 



