182 
ON THE INFLUENCE OP CLIMATE ON PLANTS. 
few cultivators who possess sufficient means for building five distinct houses for 
plants of this description ; and the taste for variety is so prevalent, that, as we have 
before remarked, a whole collection of plants is frequently sacrificed, merely because 
the cultivator is desirous of possessing as many different kinds as he can possibly 
collect. It were easy to show that a most pleasing variety might be obtained from 
plants of the same habits, and that all that can be called variety in the most 
extensive mixed collections, consists only in the difference of habit and structure, 
while there is one uniform appearance of sickliness and deterioration, and none of 
that health and beauty which can alone be pleasing to a refined taste. We have 
repeatedly witnessed the ill effects of the usual system of mingling plants of varied 
habits, and we recommend all cultivators with limited means to devote their atten- 
tion to one particular class of plants, not merely as an excellent author has observed, 
because every thing around us proves that man is ^incapable of attaining success if 
his attention be directed to too many objects at once, but also because a peculiar 
kind of treatment is necessary for different tribes of plants, and unless they are 
placed in circumstances where that treatment can be properly administered, they 
will never arrive at the degree of perfection to which they are capable of being 
brought. 
In more extensive collections, the object of these remarks may be fully effected 
by erecting glass partitions in the greenhouse for the purpose of separating the 
different tribes of plants, where distinct houses cannot be set apart for this purpose ; 
but we must and will contend, that complete success in the cultivation of any of 
the tribes before named, cannot be attained unless they are allowed a house or a 
division of a house (which is virtually the same) to themselves, and therein treated 
according to their particular nature and habits. 
Before we dismiss the subject of this and the preceding articles, it may be well 
to adduce a few observations on the influence of solar light generally upon vegeta- 
tion, and in these we shall endeavour to embrace all hardy plants. Solar light is 
the grand cause of all colour in vegetation, both in foliage and flowers ; and hence, 
an elegant author has most aptly designated the sun the great limner of nature. 
It is the action of solar light upon the leaves of plants which produces their lively 
green colour, and also elaborates the sap, converts it into pulp, imparts to the 
plant its vital energies, and sustains them in health and vigour. To solar light all 
flowers are indebted for their brilliant hues, as those which are produced in the dark 
are almost entirely destitute of colour. In fact, all colour in vegetable substances, is 
but the decomposition and partial reflection of solar light, so that no substance has 
actually any colour in itself, but the hue it presents depends upon its capacity 
of absorption of light. The sun may be said to be the prime source of colour in 
vegetation in two ways ; first, by qualifying it for, and regulating its capacity of, 
the reception of the prismatic rays, which is imdoubtedly the principal and most 
essential one ; and secondly, by its actual radiation on the substance, eliciting its 
capacity of absorption, or in other words its colour, by rendering it visible, which 
