PREFACE 
TO THE SECOND EDITION. 
The principles upon which the natural system of Botany is founded 
are to a great extent self-evident, and require little illustration. That 
those plants which are most alike should be arranged next each other, 
and that on the other hand those which have the smallest mutual resem- 
.blance should be placed at the greatest distance in the system, is ob- 
viously the method of classification pointed out by nature and reason. 
And accordingly we find that the oldest arrangements, rude and imper- 
fect as they may be, are founded exclusively upon this principle. When 
our forefathers spoke of ‘‘ grass, and herbs yielding seed, and fruit trees 
yielding fruit, of moving creatures that have life in the water, of fowl 
that fly above the earth, and cattle and creeping thing,” they employed 
the same principles of arrangement as are now in use, — rudely sketched, 
indeed, but not more so than was to be expected from the imperfect 
knowledge they possessed of science in general. At first no means ex- 
isted of appreciating the value of minute or hidden organs, the functions 
or even existence of which were unknown ; but objects were collected 
into groups, characterised by common, external, and obvious signs. From 
such principles no naturalists except botanists have deviated ; no one 
has thought of first combining under the name of the animal kingdom 
quadrupeds and birds, insects and fishes, reptiles and mollusca, and 
then of subdividing them by the aid of a few arbitrary signs, in such a 
way that a portion of each should be found in every group — quadrupeds 
among birds and fishes, reptiles amongst insects and mammalia ; but 
each great natural group has been confined within its own proper limits. 
Botany alone, of all the branches of natural history, has been treated 
otherwise ; and this in modern times. 
The first writers who acknowledged any system departed in no de- 
gree from what they considered a classification of plants according to 
their general resemblances. Theophrastus has his water-plants and 
