202. The Palaeontological Record. II. 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.” 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. 
