76 TRANSACTIONS AND PROCEEDINGS OF THE [Szss. uxix. 
What should a herbarium contain ?—Dried specimens must 
be found in the herbarium; and it is sometimes assumed that 
they alone form it; but to be of full value it must include 
much besides dried plants. The answers to the question 
must depend very largely upon the objects that herbaria are 
intended to serve. To a certain extent, all have a few 
characteristics in common; but special characteristics dis- 
tinguish various types among them, and require different 
methods of treatment. Common to all are the features that 
the specimens should have been selected to illustrate the 
points specially desired; that they should be carefully 
preserved, retaining form and colour as far as possible; that 
they should be accompanied on the sheets by drawings and 
descriptions of characters that are lost in the dried specimens, 
or are hard to be made out from them; and that their 
arrangement should render access to them easy. 
The differential features of herbaria will depend on the 
special aim in view in the formation of each. . Many 
specialised types may be found useful, differing greatly 
among themselves and from the ideal or generalised type, 
which, to a certain extent, includes features of all the 
specialised types, omitting other features. A few examples 
of limited herbaria may be indicated. Some of them are of 
great use in educational work. The aim in some is to 
illustrate structure (of stems, roots, leaves, stipules, fruits, 
etc.) ; in others, function (means of climbing, organs of defence, 
of nutrition, methods of pollination, of distribution, of 
reproduction, etc.); in others, diseases or injuries and their 
causes, whether physical or living; in others, the uses of 
plants to man (yielding foods, fibres, medicines, etc.); in 
others, the results of variations in environment, natural or 
experimental; in others, to illustrate groupings by habitat, 
or by geographical or other data. These and very many 
other motives may give origin to collections relativeiy small, 
but most valuable as aids to students, and not less so to 
biological research. Of each the value is chiefly dependent 
on the intelligence and care exercised in the selection and’ 
preservation of specimens, and on the fulness and clearness 
of the explanations and drawings that accompany these 
specimens. Such a herbarium should be noteworthy for’ 
thoroughness of execution rather than for its extent. 
