vi PREFACE 



justifiable. In these and a few similar cases the older generic names 

 have been revived. But there has lately risen a school of workers, with 

 a strong following on the Continent and in the United States, whose 

 aim is to subdivide species, genera, and Natural Orders to the fullest 

 extent. Whilst much of this is, no doubt, the result of a closer study 

 and a more critical insight than the older men practised, some of it 

 seems to represent a desire of change for change's sake. At any rate, if 

 adopted in its entirety, it would involve such confusion and readjustment 

 of nomenclature as to render its acceptance by cultivators in the last 

 degree unlikely in this country. 



In the case of nomenclature of species, I have with few exceptions clung 

 to what is known as the Kew rule of giving a plant the specific name 

 first published in conjunction with the proper genus. 



In the preparation of this work I have had the enormous advantage of 

 being able to make full use, not only of the magnificent collections of 

 living plants at Kew, but also of the herbarium of trees and shrubs which 

 has been in course of formation there for thirty years, at first by the late 

 Mr Geo. Nicholson, and during the last thirteen years by myself. There 

 are very few of the descriptions that have not been made from authentic 

 material living or dried. 



Some explanation of the term " hardy " as used in the following pages 

 is perhaps needed. There is a great variety of climate in the British 

 Isles, and the word " hardy " has a very different significance, say, in 

 eastern Northumberland to what it has at Falmouth or Cork. 

 Although we are apt, almost instinctively, to regard the softness of the 

 climate as progressing from north to south, it is, in Great Britain, rather 

 from east to west. Thus, plants can be grown on the west coast of 

 Scotland as far to the north as Ross-shire, such as Desfontainea, 

 Tricuspidaria and Himalayan rhododendrons, which are absolutely 

 hopeless in the open air at Kew. To have included a consideration of 

 all the shrubs and trees that can be grown outside in the mildest corners 

 of Great Britain and Ireland would have inconveniently and unduly 

 extended the limits of this work. A considerable proportion of them can 

 only be regarded as greenhouse plants in most parts of Great Britain. 

 The word " hardy " may be taken generally as applicable to Kew. This 

 district is fairly average in regard to temperature, although, being flat 

 and low-lying, plants are particularly liable there to injury by spring frosts. 



