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1. Herbarium
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Herbarium specimens of various Nepenthes at the Museum National
d'Histoire Naturelle in Paris, France
A herbarium (plural: herbaria) – sometimes known by the
Anglicized term herbar – is a collection of preserved plant
specimens. These specimens may be whole plants or plant parts: these
will usually be in a dried form mounted on a sheet but, depending
upon the material, may also be kept in alcohol or other preservative.
The same term is often used in mycology to describe an equivalent
collection of preserved fungi, otherwise known as a fungarium.
The term can also refer to the building where the specimens are stored
or to the scientific institute that not only stores but researches these
specimens. The specimens in a herbarium are often used as reference
material in describing plant taxa; some specimens may be types.
A xylarium is a herbarium specialising in specimens of wood. A
hortorium (as in the Liberty Hyde Bailey Hortorium) is one
specialising in preserved specimens of cultivated plants.
Contents
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 1 Specimen preservation
 2 Collections management
 3 Uses

2.  4 Largest herbaria
 5 See also
 6 External links
 7 References
Specimen preservation[edit]
Preparing a plant for mounting
To preserve their form and color, plants collected in the field are
spread flat on sheets of newsprint and dried, usually in a plant press,
between blotters or absorbent paper. The specimens, which are then
mounted on sheets of stiff white paper, are labeled with all essential
data, such as date and place found, description of the plant, altitude,
and special habitat conditions. The sheet is then placed in a protective
case. As a precaution against insect attack, the pressed plant is frozen
or poisoned, and the case disinfected.
Certain groups of plants are soft, bulky, or otherwise not amenable to
drying and mounting on sheets. For these plants, other methods of
preparation and storage may be used. For example, conifer cones and
palm fronds may be stored in labeled boxes. Representative flowers or
fruits may be pickled in formaldehyde to preserve their three-
dimensional structure. Small specimens, such as mosses and lichens,
are often air-dried and packaged in small paper envelopes.
No matter the method of preservation, detailed information on where
and when the plant was collected, habitat, color (since it may fade
over time), and the name of the collector is usually included.
Collections management[edit]

3. A large herbarium may have hundreds of cases filled with specimens.
Most herbaria utilize a standard system of organizing their specimens
into herbarium cases. Specimen sheets are stacked in groups by the
species to which they belong and placed into a large lightweight
folder that is labelled on the bottom edge. Groups of species folders
are then placed together into larger, heavier folders by genus. The
genus folders are then sorted by taxonomic family according to the
standard system selected for use by the herbarium and placed into
pigeonholes in herbarium cabinets.
Locating a specimen filed in the herbarium requires knowing the
nomenclature and classification used by the herbarium. It also
requires familiarity with possible name changes that have occurred
since the specimen was collected, since the specimen may be filed
under an older name.
Modern herbaria often maintain electronic databases of their
collections. Many herbaria have initiatives to digitize specimens to
produce a virtual herbarium. These records and images are made
publicly accessible via the Internet when possible.
Uses[edit]

4. Herbaria are essential for the study of plant taxonomy, the study of
geographic distributions, and the stabilizing of nomenclature. Thus, it
is desirable to include in a specimen as much of the plant as possible
(e.g., flowers, stems, leaves, seed, and fruit). Linnaeus's herbarium
now belongs to the Linnean Society in England.
Specimens housed in herbaria may be used to catalogue or identify
the flora of an area. A large collection from a single area is used in
writing a field guide or manual to aid in the identification of plants
that grow there. With more specimens available, the author of the
guide will better understand the variability of form in the plants and
the natural distribution over which the plants grow.
Herbaria also preserve a historical record of change in vegetation over
time. In some cases, plants become extinct in one area or may become
extinct altogether. In such cases, specimens preserved in an herbarium
can represent the only record of the plant's original distribution.
Environmental scientists make use of such data to track changes in
climate and human impact.
Many kinds of scientists use herbaria to preserve voucher specimens,
representative samples of plants used in a particular study to
demonstrate precisely the source of their data.
They may also be a repository of viable seeds for rare species.[1]
The Value of Herbaria for Plant
Conservation
Category:
Research
An often repeated statement is that “you must know what you have
before you can conserve it” …but how do you know what you have in the
first place? Field biologists have been working on this questionfor
literally hundreds of years by conducting inventories, from general
natural history inventories to small, highly detailed plot studies of flora

5. and fauna. These inventories result in preserved specimens,which in
the case of plants, are placed into herbaria along with their associated
original locality information. Herbarium specimensthen serve as
documented proof of a plant’s occurrence at a specific time and place.
Herbaria have the advantage over living collections that if well cared for,
can last for hundreds of years if not longer. Although living collections
are valuable for many purposes,they are expensive and difficult to
maintain in cultivation for long periods of time. It is the vast number of
preserved plants and their longevity in storage that make them ideally
suited for the purpose of archiving a host of information on plants and
their habitats.
Worldwide,herbaria contain approximately 300 million
specimens,nearly all with labels that include collectionlocality
information. The labels may also contain a variety of information, such
as ecology,flowering time, ethnobotany, geology,pollination,
fragrances, and dispersal. Other information can be gleaned from
herbarium labels such as which plants grew where over time and when
did a particular invasive plant invade a particular region. Herbarium
label information is most oftensummarized and published in floras and
monographs,though its real potential of biodiversity mapping is being
realized through the accumulation of its data on computers in
combination with global information systems. One of the most valuable
outcomes of this type of work is the ability to determine which areas are
the most species-diverse or rich in endemic-species,allowing them to be
given higher conservation priorities. A great challenge for herbaria,
though, and the biologicalsciences in general, is capturing plant label
information electronically so that it can be made widely available for
conservation purposes.
Perhaps of greatest importance,herbaria are potential
repositories of genetic information for every species of plant known to
science. Techniques are continually being refined to extract DNA and
other chemical information from plants preserved decades or even
centuries ago. Newer techniques of DNA extraction, particularly
amplification, allow for smaller and smaller pieces of herbarium material
to be required for genetic analysis, thus preserving the herbarium
specimensforother types of studies. Recognizing that some traditional
preservation techniques may hinder the future extraction of DNA,
herbaria and botanical gardens are adapting and placing more emphasis
on the collectionof materials in silica gel and cryopreservationof seeds
and tissues.

6. As a fundamental tool for plant taxonomy, herbaria play other
roles in plant conservation efforts. The simple act of correctly identifying
a plant species is necessary for conservation, providing the language
(Latin names) for biologists of far-flung regions and ethnicities to be able
to accurately communicate with each other. Herbaria facilitate
taxonomic studies by enabling collections from diverse habitats and
localities to be studied in one place. Plant speciesvary in size and
shape across their geographicalrange, and this variation can be
observed and studied easily in a herbarium. Herbaria also serve as a
place to depositvoucher specimens from scientific studies where the
correctidentification of a plant is essential.
Considered as relics of the past by some biologists,there is a
renewed appreciation in the vast amount of information stored in
herbaria and its potential to help us understand, and conserve life on
earth
http://www.selby.org/learningandgrowing/articles/value-herbaria-
plant-conservation