CHAPTER XIX 
VARIATION AND THE EVOLUTION OF SPECIES 
WHEN we look round upon this land of England, its 
pleasant fields and placid meadows, its hedgerows, pools, 
and woods, and the long stretches of purple heath and 
desolate moor, the question naturally arises, Whence did 
it all come? What is the past history of these fields, 
these woods, these vast hosts of many-tinted flowers ? 
Is it possible for us to learn something of the previous 
history of these humble populations—their struggles and 
conquests, to understand why one race has established 
a dwelling-place here and another there, and to reconstruct 
in mental vision the part each and all have played in the 
development of that vegetation which constitutes to-day 
our native flora ? 
These questions occur to the inquiring mind, but to 
most there is no answer. Our knowledge, however, is 
increasing, and every year some light is being thrown upon 
the dark places. 
The plants which we see around us are unlike those 
whose remains are preserved to us in the rocks. The 
further we recede in time, the more unlike the vegeta- 
tion becomes to that which is living to-day. The number 
of different forms now inhabiting this country is enor- 
mous. In the London Catalogue of British Plants 
over 2,000 species of seed-plants and ferns are enu- 
merated. Whence arose this great assemblage of plants 
and this wealth of variation ? Two theories are possible. 
Either each species is constant and was separately created 
—the Special Creation theory—or they have all arisen 
by modification and variation from pre-existing forms, 
more or less unlike them, developing under the control of 
natural laws—the Evolution theory. It is now generally 
agreed that only the latter theory can account for the facts. 
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