CHAPTER XVIII. 
THE EVIDENCE FROM PALAEOPHYTOLOGY. 
Ir has been remarked above (Chapter I.) that the only direct and positive 
clue to the sequence of appearance of Plant-Forms in past time upon the 
earth is to be obtained from the study of fossils. Luminous facts derived 
from them are beginning to shed a fresh and direct light upon problems 
hitherto obscure; and the last quarter of a century especially has shown 
how greatly a knowledge of the fossil forms may advance the true per- 
ception of affinities of certain groups of plants now living. 
But the success which has already attended Palaeontological investi- 
gation, and has Jed to such important results, must not be allewed to 
disguise the limits which circumscribe this branch of enquiry: nor should 
it unduly raise the hope that the area of fact available for comparison 
with forms now living will be indefinitely extended. It can hardly be 
anticipated that data derived from fossils will ever take a decisive place 
in discussions of the primary origin of the sporophyte. In the mind 
of the Morphologist there can be no spirit of depreciation of the recent 
advances. of Palaeophytology, but rather a very high estimate of their 
value: nevertheless he cannot help recognising how inadequate the 
evidence drawn from fossils is in its bearing on such questions as those 
discussed in the foregoing chapters. Hitherto it has given no clue 
whatever to the origin of the Bryophyte sporogonium: nor does it 
materially assist in resolving the problem of the origin of the leafy 
sporophyte, or of its adoption of a free-living habit: nor, again, does it 
indicate with any decisiveness the evolutionary relationships of the great 
phyla of the early Pteridophytes. All these questions deal with events 
which we may presume to have preceded the existence of the earliest 
fossils of which any exact record has hitherto been discovered.} 
1T am unable to share the very sanguine view of Mr. Arber (Azals of Botany, 1906, 
p. 216), who remarks that ‘‘the imperfection of the Record, largely exaggerated in the 
past, can be wholly neglected where we are considering the larger divisions of the vege- 
table kingdom, such as phyla, classes, or groups of Plants.” 
