THE EVOLUTION OF PLANTS. 
17 
THE EVOLUTION OF PLANTS. 
Illustrated by the cultivated Nature of Gardens. 
By Mr. R. Irwin Lynch, Cambridge Botanic Gardens. 
[Read March 13, 1900.] 
I. — Evolution in Nature. 
II. — Evolution in the Garden. 
III.— Illustrations, A, of Hybrid Origin ; B, not of Hybrid 
Origin. 
1. 
My point of view and the treatment of my subject may be better under- 
stood, perhaps, if I mention that in dealing with this subject I propose 
to demonstrate, so far as may be possible, the real identity of all evolution, 
whether it takes place in wild nature or in the cultivated nature of 
gardens. A very low view is often taken of plants that originate in the 
garden, and I shall be disappointed if I do not succeed in raising, to some 
extent, the status of garden hybrids, species and varieties, as entities that 
are worthy of the same recognition that is accorded to the species, the 
varieties, and often the hybrids found wild in nature. Evolution in nature 
is fully recognised by every intelligent mind of this last year of the 
nineteenth century, but those very same minds have often but little 
respect for the undoubted evolution that goes on before our eyes in the 
garden. Bailey writes, not long ago : This notion that a species to be a 
species must have originated in Nature's garden and not in man's has 
been left over to us from the last generation ; it is the inheritance of an 
acquired character." I quite agree with his sentiment, if not quite with 
the last part of his sentence, which was intended merely, no doubt, to add 
emphasis. 
I propose to deal only with the main factors of evolution, because, 
certainly, it would be impossible to do more, satisfactorily, in so vast a 
subject, and for my purpose, also, the main factors are quite sufficient. 
I have to show, as well as I can, the means or mechanism by which 
evolution comes about, and I have to show a parallel, or strict similarity, 
between the operations of Dame Nature uncontrolled and the operations 
of Dame Nature more or less controlled in the garden. I hold of course 
the Darwinian theory as the true theory, which, in its main elements, 
must contain all that is most essential and for ever true. Huxley in his 
Life of Darwin " wrote : " I venture to affirm that, so far as my know- 
ledge goes, all the ingenuity and all the learning of hostile critics have 
not enabled them to advance a single fact of which it could be said, This 
is irreconcilable with the Darwinian theory." That theory, to my mind, 
is essentially dependent upon three principal factors. 
We have first of all variation, without which there could be no evolu- 
tion ; secondly, we have the struggle for existence, without which there 
