vI Preface. 
certain of their vegetative parts. This procedure should be useful for com- 
parative purposes both in the region dealt with and elsewhere. Obviously in 
deciding certain points, such as relative size or texture of leaves, the personal 
equation comes in, but where many species are concerned this should not 
affect the general era 
No attempt is made at completeness. On the contrary, owing pa to 
the limited space available and partly to the great variety of New Zealand 
plant communities, the matter is greatly condensed. Many species, especially 
those which are rare, are not mentioned; it is, after all, the common ones 
which are of prime importance. 
The reader not acquainted with the New Zealand flora has been kept in 
mind. The leading physiognomic plants are treated at considerable length for 
each section of the vegetation, while the growth-forms of many species are descri- 
bed when they first appear in the text. Vernacular names are specially avoided. 
Since 1914 I have ceased calling the tussock formations of New Zealand 
“steppe” because they do not fit into the usual plant-geographical conception 
of that term. I have therefore substituted “tussock-grassland” as a self ex- 
planatory name for a distinct type of vegetation. This term appears once or 
twice in the latter part of the book, but generally “steppe” remains. It must 
be remembered, then, that the latter is ecologically distinct from true steppe, 
indeed it has much wider physiological capabilities and can maintain itself 
intact under a surprising variety of conditions. 
The meaning of “epharmonic”, as used in the biological chapters, must 
be explained, since its significance according to my usage is somewhat different 
to Vesque’s definition of the term. In this book, and in my other publications, 
by “epharmonic variation” is meant a change in its form, or physiological 
behaviour, beneficial to an organism evoked by the operation of some environ- 
mental stimulus. Such a change may be called an epharmonic adaptation as 
distinguished from such adaptations as cannot be traced to any direct action 
of the environment. 
Apart from those mentioned in the text with regard to photographs, or 
special information, which they have generousiy supplied, many botanists and 
others have given valuable and much-appreciated assistance with regard to 
this book. To name all would extend this preface far beyond its alloted 
space, to give merely a partial list would be invidious.. Therefore, I thank 
most sincerely one and all. 
I must, however, express my gratitude to Prof. Dr. L. DIELS who has. 
devoted much valuable time to seeing the book through the press. Nor can 
I neglect thanking Prof. Dr. A. ENGLER for having allowed me the great 
privilege of contributing to this famous series of monographs of which he 
and Prof. Dr. O. DRUDE are the distinguished Editors. 
Ngaio, Wellington, New Zealand, a 
January ı5th, 1921. Es Cockayne 
