PREFACE. 
In order that this Report should answer the ends for which 
the Survey was ordered, the descriptions of the Trees and 
Shrubs are arranged according to the Natural System. This 
has been done, not from undervaluing the artificial system of 
Linneus, which must still continue of use in aiding to find the 
name of a plant and its place in the Natural System, but from a 
conviction of the incomparably greater value of the latter. The 
artificial system is based essentially on distinctions drawn from 
the stamens and pistilsalone. The Natural System, on the con- 
trary, takes into consideration not one part only, but every part 
and whatever relates to it,—the seed, from the development of its 
embryo to its germination, the growth, formation and arrange- 
ment of the wood, bark, buds and leaves, and the flower and fruit. 
It is found that plants which resemble each other in the external 
forms of their more essential parts, have a similar resemblance 
in properties and uses, and require similar modes of manage- 
ment and culture. The adoption of the Natural System is, there- 
fore, particularly important in a comparatively new country lke 
ours. Upon the culture, properties and uses of many of our 
trees and shrubs, few or no experiments have been made. We 
must learn what modes of culture are likely to answer best with 
them, by observing what modes have been successful with well- 
known plants of the same families and affinities, in the old 
countries. Of many of them, the value in building, and the 
various mechanic arts, in dyeing and tanning, and as furnishing 
articles of food, or materials for medicine, are not yet known. 
We shall be likely to find them most readily by looking for uses 
similar to what are known to belong to plants most analogous to 
them. ‘If there is,’ says De Candolle, ‘a country where the 
theory of analogy between forms and properties may become 
eminently useful, it is North America, which, situated in the 
same latitude as Europe, is occupied by analogous vegetation.” 
