vi 
PREFACE. 
book of systematic botany, whereas the genera are treated 
much more briefly unless they show some feature of special 
interest that is not common to the family. This mode of 
treatment has been adopted for two reasons — to prevent 
the student from regarding the genera as isolated and un- 
connected units, and to avoid repetition. To give the 
generic characters in a work of this kind would... enor- 
mously increase the bulk. The treatment adopted involves 
a good deal of cross-reference, but will impress upon the 
student the relationships of the members of the vegetable 
kingdom to one another. 
“ Finding that Part II was still wanting in co-ordination, 
I wrote Part I to supplement it. . . . Our existing text-books of 
morphology are mostly out of date and have little evolutionary 
basis ; the principles of classification and evolution are not 
explained in the elementary books, and the advanced books 
take for granted that the reader is familiar with them ; no 
good text-book of the natural history of plants or of their 
geographical distribution is at present available in English. 
I have therefore written Part I in such form that it makes 
in itself a fairly complete treatise upon these subjects; at 
the same time it is throughout designed for purposes of 
cross-reference from Part II, and may be itself expanded to 
almost any extent by reference to Part II for details. The 
method of treatment adopted is novel, and is based on that 
which I have employed for several years in my lectures. 
The morphology of the vegetative organs is dealt with 
generally in Chapter I, and in more detail in Chapter III 
in connection with the natural history and geographical 
distribution ;... the morphology of the flower is treated in 
full in Chapter I, in connection with its natural history 
and from an evolutionary standpoint. I have adopted this 
method both because it seems to me to make more clear 
the meaning of the morphological phenomena and the 
