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living plants. While botanic gardens can, at best, cultivate but a 
few thousand species, great herbaria contain millions of dried 
specimens. Further, many plant families are, for one reason or 
another, not suitable for cultivation and it is desirable that they 
be represented by at least a few herbarium specimens. 
In addition, we have the material (some of it tropical) which 
has been accumulated on expeditions in which members of the 
Brooklyn Botanic Garden have participated and which has been 
the basis of the published results of the explorations. A knowl- 
edge of the flora of many regions has been made possible by the 
ected by travellers who were not 
— 
study of herbarium specimens col 
botanists. 
Herbarium material is also indispensable to investigators who 
are doing monographic work on different plant groups or regions. 
In fact, most systematic work must be done with preserved speci- 
mens, the plants being collected in the field but studied at con- 
venience and leisure in the herbarium. The specialist may thus 
have at his disposal a rich representation of a given group or 
region, and moreover all the specimens in a herbarium are, so to 
speak, “in flower” at the same time and at all seasons of the 
vear. Reciprocally, such work always benefits a herbarium, which 
steadily increases in value as careful arrangement and authori- 
tative determinations of its eas are made. Mere size is 
not, of itself, an indication of the value of a collection, but rather 
the state of organization, perfection of the specimens, availability 
for reference, and the degree of reliability of carefully selected 
material for desired purposes. 
The scientific value of a herbarium is enhanced by the “ type 
specimens it contains. A “type” specimen may, in general, be 
defined as the specimen on which the original description of a 
species is based. Our own herbarium possesses many type speci- 
mens, especially in the group of the Fungi. 
A herbarium is also of value in numerous incidental ways such, 
for example, as the preparation of illustrations for botanical pub- 
lications, herbarium material being available in rich variety at any 
ay 
season of the year. In several instances, herbarium specimens 
have supplied very old seeds of definitely known age for experi- 
mental studies of the longevity of seeds. These studies, in turn, 
