Collection Maintenance.
The herbarium collections of plant material
are the working stock for the taxonomists and
other scientists who can make use of them. They
are also the repository of basic botanical knowledge
for the country of Trinidad and Tobago.
Clearly they need careful curation and maintenance,
and this is one of the main jobs of the herbarium
staff.
The main collections are of flowering plants,
kept on herbarium sheets in species folders
within genera, and arranged by plant family
in an air-conditioned room in wooden cupboards
with one or two folders on each of many shelves.
The air-conditioning is necessary mainly to
reduce the humidity to prevent the deterioration
of the plant material through the action of
fungi and bacteria.
There are subsidiary collections of lower plants,
such as ferns, fungi and algae, also kept in
similar conditions. Small collections of wood,
seeds, and fruit are also maintained by the
herbarium.
The method of storage must allow for almost
indefinite storage of the specimens, some of
which are more than 100 years old. Dried plant
material is very delicate, and so must be handled
with great care, and as seldom as possible.
The damage caused by fungi and bacteria is
actually less important than that done by insects,
so it is important to disinfest the new plant
material before it is mounted on the herbarium
sheets and placed in the main collection.
It is also necessary to continually protect
the main collection from the build-up of insect
populations in the cabinets. This is done on
a continuous basis by placing the herbarium
folders in a deep freeze for 1 week, and then
replacing them on the shelves. The complete
cycle for all the specimens takes about 8 months.
At infrequent intervals professional fumigation
of the herbarium storage room is done with 'Vikane'.
