PREFACE 
J N publishing this book on Irises, I am fully aware that it is not yet possible to give a 
complete account of the Iris genus. This could only be done by one who had the 
leisure and the opportunity first of all to go to all the localities in which Irises have been 
found or in which new species are likely to exist, and then to grow all the species side by 
side and note their affinities and differences. 
Meanwhile, this book contains an attempt to put together the available facts and to 
indicate the gaps in our information. It is hoped that it may lead to the filling up of some 
of these gaps and to a more general appreciation of the various species of Iris. 
The reader’s attention is directed to the explanation given in the Introduction of the 
method on which the book has been compiled. To the professional botanist this may appear 
unorthodox in its neglect of local Floras, but this neglect was inevitable in view of the 
uncertainty that has prevailed as to the definition of the various species. 
With regard to the arrangement of the species in groups, it seemed better to take 
together those plants which are obviously related to one another by their whole appearance, 
than to pick out some one character or set of characters and base on it an artificial grouping, 
which would bring together the most widely different species. 
This plan has made it impossible to give a really satisfactory clavis or key to the 
Apogon section, but it is hoped that the definitions of the characteristics of the various 
groups will be a sufficient guide in assigning an Iris to one or other of them. To each 
group there will be found prefixed a key to the species included in it. 
The illustrations were all taken from plants growing in the open in my garden 
here, with the exception of /. Lortetii , which came from the south of France. 
It only remains to say that I shall be very grateful for any criticisms of the information 
here collected and for help towards a better knowledge of those species with which we are 
still unfamiliar. 
W. R. DYKES 
Charterhouse, 
Godalmino 
November 1912 
