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TREATMENT OF THE GENUS GENTIANA. 
Six or seven of the species comprised in this genus, including the beautiful 
G. acaulis, verna, and Pneumonantke, inhabit particular parts of the British 
Islands, though they are likewise found in other countries of Europe. The more 
truly exotic kinds affect nearly the same description of localities, these last differing 
mainly in a single point of minor importance. As it is essential to keep facts of 
this nature before the mind when endeavouring to determine what is the fittest 
course of treatment, we shall state, in a more detailed manner, the peculiarities of 
position, atmosphere, and soil, which most Gentians enjoy in a wild state. 
The first thing that must strike an inquirer into this subject is, that the majority 
of these plants are confined to elevated sites. There are certainly a few which 
thrive in common pasture land ; and we have before us a letter from a kind corres- 
pondent, in which we are informed that a species greatly resembling the G. gelida, 
and which is presumed to be identical, " grows in great profusion in the moist 
peaty meadows in some parts of Bohemia, especially in the skirts of the Pine 
forests near Marienbad." We infer from the proximity of this spot to Pine woods, 
that it also must be at a considerable altitude, since Pines are seldom denizens of 
the plains ; and many other species of Gentian are to be gathered solely on high 
ranges of mountains, such as the Alps, the Pyrenees, and those of Caucasus. Our 
own indigenous species are mostly scattered over hilly tracts, and there is only one, 
the G. Pneumonanthe, which delights in moist heathy places. 
Next to the elevation of their locality, and actually arising therefrom, is to be 
noticed the nature of the atmosphere by which they are surrounded. This is much 
rarer than that in which we cultivate them, and besides the moisture of the ground 
being more readily carried down to the valleys on account of its relative position with 
respect to them, the remainder of it is more speedily dissipated into the air by the 
process of vaporization, which is always facilitated by the rarity of the atmosphere, 
because less pressure is then exerted on terrestrial matters, and there is a greater 
vacuum to admit them when volatilized. Moreover, although the increased altitude 
would seem to expose them to more piercing winds, and severer weather, by being 
nearly all deciduous, and completely dormant in the cold season, the effects of 
winds are more useful than otherwise, for they keep the earth dry and prevent 
precocious development. The more Alpine species are, however, fully protected by 
snow, which extends over them its spotless screen, and preserves around them both 
a bearable degree of moisture and temperature. It should be observed, too, that 
in mountainous regions the summers are especially brilliant, and vegetation 
receives the unlimited operation of solar heat and light. 
We now turn to the soil. In the communication from which we have quoted, 
and the fact subsequently recorded concerning G. Pneumonanthe, it is evident that 
those two species prefer a humid heath-soil, the wetness of which we may fairly 
assume to be a transient provision of nature to stimulate their growth, rather than a 
constantly resident supply ; as neither Heaths nor Gentians could resist the 
tendency to repletion and decomposition which such circumstances would superin- 
