222 SCIENCE OF THE STUDY OF TREES. PART IF. 



such as the bark, leaves, flowers, fruit, &c., are of importance. Not only are 

 trees used in their different parts after being felled, but, in some cases, a part 

 of their products is gathered yearly; and some sorts, both of trees and shrubs, 

 are in perpetual use in a living state, as fences for separation or enclosure, as 

 avenues for shade, and as belts or screens for shelter. The ornament which 

 trees and shrubs afford to gardens and grounds may also be considered as an 

 important part of their use. 



The rearing and culture of trees form an important part of their economical 

 history ; and require to be treated of, not only in the history of each individual 

 species, but when treating of trees collectively in plantations. The commence- 

 ment of the process of rearing is with the gathering of the seed, or the taking 

 off of the cutting, or the forming of the layer ; and the termination of the pro- 

 cess of culture is with the felling of the tree, or the cutting down of the shrub. 



CHAP. IV. 



SUMMARY OF PARTICULARS TO BE TAKEN INTO CONSIDERATION 

 IN PREPARING THE DESCRIPTION, AND NATURAL AND ECONOMI- 

 CAL HISTORY, OF TREES AND SHRUBS. 



In the three preceding chapters we have treated of the science of trees, as 

 pictorial objects, or parts of general scenery ; as organised beings, or botanical 

 objects ; and as forests or plantations, influencing the physical circumstances 

 of a country, and the condition of man. Our object in those chapters was, 

 to give a general idea of the extensive nature of the study of trees ; and in 

 the present chapter we propose to enumerate all the particulars which require 

 to be taken into consideration in giving the specific character, description, 

 history, and uses of each individual species, race, or variety. These parti- 

 culars, arranged in the order in which they will stand in the succeeding part 

 of this work, are as follows : — 



1 . Classification. We shall adopt the natural system, chiefly for the sake of 

 aiding us in generalising on the genera and species which each order and 

 tribe contains; and we shall refer, for the definitions of these orders 

 and tribes, to the writings of Professor De Candolle and Dr. Lindley, 

 and more especially to the Prodromus of De Candolle, and Lindley's 

 Introduction to the Natural Si/stem, and to his modification of that work in" 

 his Key to Structural, Physiological, and Systematic Botany, published in 1 835, 



2. Genera. The genera of each order or tribe, with their characters, will be 

 given immediately after the general character of the order or tribe, in the 

 manner of De Candolle, and as adopted by G. Don, in his edition of 

 Miller's Dictionary. 



3. Distinctive Characters. The species, races, or varieties, of each genus, 

 will be enumerated immediately after the enumeration of the genera; and 

 their distinctive characters will be given, with the English name, habit, co- 

 lour of the flower, and time of flowering, and year of introduction into 

 Britain. 



A. Identifications. These are references to some of the principal works 

 in which the same plant has been described under the same name. 



B. Synonymes. These will be given to as great an extent as can be done 

 with certainty, or apparent advantage. Not only will the scientific 

 synonymes be given, but also those in common or ancient use in this 

 country, and the popular names in other countries. 



C. Derivations will be given, not only of the generic and specific names, 

 but of all the synonymes, where doing so is likely to prove either in- 

 structive or interesting. 



