464 
PHYTOGRAPHY. 
BOOK IV. 
CHAPTER VI. 
OF HERBARIA. 
To a botanist who studies the science with much attention, 
and with a view to becoming perfectly acquainted with it, 
neither books nor the most elaborate descriptions prove suf- 
ficient. He finds it indispensable to have continually within 
his reach some portion of as many species as he can procure. 
If he has admission to a botanical garden, a great many 
species may thus be readily accessible; although, even in 
such a case, it is only at particular periods that he can study 
the flowers and fruit of any of them : a garden, too, seldom 
contains more than a fifteenth or a tenth of the number of 
known species ; and far more frequently not a twentieth. 
For these reasons, botanists have contrived a method of 
preserving, by drying and pressure, specimens of plants which 
represent all that it is most essential to recognise. A" collection 
of such specimens was formerly known by the expressive name 
of Hortus Siccus ; but is now universally called an Herbarium. 
If well prepared and arranged, such a collection is invaluable 
to any working botanist, because it enables him instantly, at 
all times, to compare plants themselves with each other, and 
with the accounts of other botanists ; or to examine them with 
reference to points of structure not previously considered. It 
will, therefore, be useful to explain, shortly, the best modes of 
preparing, arranging, and preserving herbaria. 
What is called the specimen of a plant, is a small shoot 
bearing flowers and fruit, either together or separately, pressed 
flat and dried, so that it may be conveniently fixed upon a 
sheet of paper. As a plant is, in all cases, an aggregation of 
individuals growing upon exactly the same plan, and pro- 
ducing the same kind of reproductive organs, it follows that 
a single shoot, comprehending leaves, flowers, and fruit, is a 
representation of the largest tree of the forest, and will give as 
