Vol. Il., No. 8, MARCH, 1885.,] 
BOTANICAL EVOLUTION.* 
In endeavouring to place before you in the following short 
course of lectures the subject of Botanical Evolution, I have 
set myself a somewhat difficult task. As far as I know, the 
subject has not hitherto been treated of by itself, and though 
the principles of the doctrine of evolution in their application 
to vegetable life are to be found scattered broadcast in many 
botanical works, yet the collation of the most interesting facts and 
their presentation in somewhat regular sequence, is a work of 
considerable labour. Besides, those who are familiar with biclogical 
subjects, in attempting to expound such a subject in popular 
language, have to abandon their usual technicalities, and seek to 
express themselves in familiar everyday words. And they have also 
to remember that the majority of their fellow-beings are not familiar 
even with what may be considered the rudiments of biological 
science. Therefore, in dealing with the subject of this. course, I 
think it advisable in the first place to enter into a short statement of 
the doctrine of evolution, particularly in its application to plants. 
In endeavouring to place shortly before you this doctrine I shall 
point out certain facts and certain theories. Facts as we know—but 
are apt to forget—are things “that winna’ ding”; the theories may 
be upset or replaced if they are unable to explain what they profess 
to do. 
The facts which I shall insist on are:—l. The tendency to 
individual variation which exists in all animals and plants; 2. The 
tendency of all organic beings to reproduce others almost but not 
quite exactly resembling themselves; 3. The enormous production of 
organic life on the globe, far in excess of the amount which can 
possibly survive to maturity, and the consequent struggle for 
existence and the survival of the fittest in the race of life; 4. The 
occurrence of rudimentary organs both in plants and animals; 5. The 
geographical distribution of plants and animals; and 6. Palentology 
and the imperfection of the geological record. 
1. The first fact then to which I refer is the tendency to 
variation which exists in all animals and plants. No fact in the 
domain of nature is more universally admitted than this. Take our 
own case, first, as an example. In the same family—with the 
very rare exceptions recorded of certain twins—there are no two 
individuals alike. There may be great general and also special 
resemblances between any two members, and a strongly marked 
family resemblance, but in minute detail, the physical structure—-to 
go no further—displays infinite small variations. Nor do we wonder 
at this fact, because seeing that parents are never quite alike, it is 
quite impossible that their offspring can resemble both parents 
exactly. The comparison may be carried further, and we might 
assert with perfect safety that among the numerous millions of 
* Abstract of a course of three lectures delivered to the Otago Institute, in 
ete 1884, by Geo. M. Thomson, F.L.S., Science Master in the Dunedin High 
chools. 
