Fes. 1905. | BOTANICAL SOCIETY OF EDINBURGH. 75 
formation obtainable from the living specimens by reference 
to structures not present in the particular stage of growth 
(e.g. fruits, seedlings), or to compare with the living plants 
the corresponding parts of plants of the same species grown 
in different environments, or of allied species, or of plants 
of other kinships, but of very similar aspect. Thus, to both 
teacher and pupil the herbarium becomes a most useful sup- 
plement to the living plants. Further, the herbarium becomes 
a very valuable biological record when it contains series of 
specimens that illustrate, in a far more trustworthy way than 
descriptions and figures alone could, the progress of continued 
experiments and observations on the interactions of plants 
among themselves, and as affected by their environments. 
From such carefully prepared and preserved records much 
information may be expected with regard to the evolution 
of the various forms of plants. The practical value of such 
knowledge in agriculture, gardening, and forestry is self- 
evident. 
Akin to such investigations, though regarded from another 
standpoint, is the endeavour to appreciate the effects produced 
by man upon the flora of a country, and for this also a 
herbarium is of very great value. It is true that the greed 
of mere collectors has endangered the survival, or even has 
led to the local extinction of a few rare or very local plants ; 
but local rarity or extinction has been caused far more often 
by man in other and less evident ways, of which frequently 
no record survives, or, if it does, it is due to the local lists or 
the local herbarium, which fill a useful, if relatively incon- 
spicuous place in botanical research. How great the changes 
due to man have been in local floras can scarcely be realised 
even after diligent investigation; but their interest and 
importance render them worthy of study. 
Still another reason for the formation of a herbarium has 
been already alluded to. It is that (except where under- 
taken wholly to gratify the mere desire of collecting for the 
sake of possession) it affords a useful training to the person 
who forms it. 
That a herbarium “ finds its principal use in the authentica- 
tion of botanical discoveries made in distant lands” is a 
statement based on a singularly narrow view of its true 
value in botanical education and research. 
