Herbarium: Meaning, Functions and Kinds

In this article we will discuss about Herbarium:- 1. History of Herbarium 2. Meaning of Herbarium 3. Functions 4. Kinds 5. Important Herbarium 6. Herbarium of Other Groups of Plants. 

Contents:

1. History of Herbarium
2. Meaning of Herbarium
3. Functions of Herbarium
4. Kinds of Herbarium
5. Important Herbarium of the World
6. Herbarium of Other Groups of Plants

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1. History of Herbarium:

The art of herbarium was initiated by an Italian taxonomist from Bologna, Italy, named Luca Ghini (1490-1556), who collected plants, dried and affixed them on paper with gum, in the form of herbarium specimens. He had a collection of about 300 specimens in 1551.

Not much is currently known about his herbarium, which is now lost. Later, his student Gherards Cibo,continued this art, and his herbarium is still preserved in Rome. In the middle years of the sixteenth century, three Ghini students, namely Aldrovandi and Cesalpino from Italy and Turner from England, also made their own herbaria.

Cesalpino’s herbarium, currently in Firenze, is very important, as it can be compared with his book “ De Plantis Libri XVI”, which introduced a scientific approach to the study and classification of plants. An Englishman, John Falconer, Who probably met Ghini in Italy, prepared a herbarium in 1553.

There are currently more than twenty herbaria created before 1600, preserved  in various European cities. The first recorded written published is that of the native of Brussel, Adrian Spieghel, in, “Isagoges”, a treatise of botany, which dates back to 1606, dealing with how to dry plants and what kind of paper one should use, along with other accurate information.

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2. Meaning of Herbarium:

The word herbarium (plural herbaria) was however, first applied by Pitton de Tournefort, in the book “Elemens”. Other herbaria were developed during the seventeenth century. A very good example is that of the Museum National d’histoire Naturelle in Paris. During this period, many collections of exotic plants were created, as a result of the many geographical explorations.

Some of these exotic herbaria have been of great importance for the advancement of scientific knowledge of some areas like Asia or Africa, and can be currently seen in a few European museums.

It was Linnaeus who first started the Current practice of mounting the plant specimens on separate sheets and storing them horizontally. Before Linnaeus, the actual practice was to sew dried plants on a sheet by thread and binding them into volumes.

With the simple beginning by Linnaeus, herbaria today have developed into facilities for storing millions of specimens. In the earlier days the herbaria included plants of local or regional significance. But now, most of the herbaria include plants from different parts of the world and have developed into centres of advanced research in the field of taxonomy.

3. Functions of Herbarium:

A modern herbarium serves numerous valuable functions. Some of the important functions of herbaria are as follows:

(a) A herbarium serves as an invaluable conservatory of plant material of flora. collected from different parts of the world. Thus, they provide at one place, basic material for study of flora and vegetation of different places or regions.

Since it serves as a permanent record of flora of those regions, collections in the herbarium provide evidence of the vegetation of a region, which may be destroyed due to some natural catastrophes.

(b) The specimens in the herbarium carry valuable data on their labels. These include data on habitat, habit, local names, colour of flowers or other characters of the plant, native uses of the plant, abundance or frequency of the species, associated plants, etc.

Such data provides valuable material for proper morphological description and range of variation of a similar plant collected from a different region, range of distribution and variation in its uses in different places. Thus, a herbaria provide data for botanical, ethno-botanical and phytogeographical studies.

(c) The herbarium serves as an aid in teaching botany to students in institutions where a herbarium is present, as it helps a teacher to show his students a plant specimen which may not be available fresh at the time of giving the course. It also helps students to identify local plants collected by them.

(d) Preserved specimens of herbaria are used in almost all types of taxonomic research. It is believed to be an essential requirement for biosystematics research today, for correct identification and nomenclature of the plant under study.

Since in biosystematics studies, a work may need material of a taxon from far and wide in studies involving ‘all world species’, it may not be always possible for a researcher to visit different areas of occurrence. In such cases one has to largely rely on the resources of herbaria.

(e) The specimens in the herbaria are very often used as a source of material for anatomical, palynological and chemo-taxonomical studies.

(f) The herbaria provide important data on actual places of occurrence, time of flowering and fruiting, associated species and other data for researches in embryology, cytology and ecology.

(g) The herbaria have proved to be very valuable source of information for ethno-botanical researches as many native uses of plants are recorded on the herbarium sheets.

4. Kinds of Herbarium:

Depending upon the interest of the organization or institution, the contents of holding and the labels and notes on the sheets in a herbarium vary accordingly.

(a) The herbaria of organizations like Botanical Survey of India contain all collections from any part of the world.

(b) Those institutions, which are interested in drugs and medicines, have herbaria, which include specimens of plants of known medicinal properties.

(c) The herbaria of the universities and colleges generally contain specimens only of interest for teaching or those included in the syllabus and research.

(d) The herbaria of Agricultural Colleges and Universities include specimens of crop plants and weeds of cultivated fields.

5. Important Herbarium of the World:

A large number of herbaria have been established in different parts of the world over a period of the last four hundred years.

According to a census conducted nearly ten years ago, there are about one thousand two hundred recognized herbaria in the world, excluding a large number of smaller unrecorded herbaria of various universities, colleges, pharmacies, etc. The first such herbarium was founded in the University of Padua, Italy, in 1545, along with the establishment of the first botanic garden in the same year.

The following tables (Tables 1-3) gives the name of the institution, location, approximate number of sheets, year of founding and the standard abbreviation of some important herbaria in different parts of the world :

6. Herbarium of Other Groups of Plants:

It is also possible to build a herbarium with ferns and other non-vascular plants such as lichens and fungi. Here is a brief description of the main topics regarding this particular kind of herbarium.

a. Pteridophytes:

The ferns and allied plants are grouped together in the pteridophytes. Typically, pteridophytes have photosynthetic organs called fronds, which resemble the leaves of vascular plants. Most of the ferns have their spores in sporangia usually found in the margins or under the fronds. This is a very important feature, as these plants must be collected when they are fertile, otherwise no identification will be possible.

In many allied plants the spores are arranged or aggregated in different manners. If one is interested to collect these plants, one should carry a x1O hand-lens to look for the presence of sporangia. To gain a successful identification it is also advisable to collect part of the rhizomes, examining their covering elements and the appearance they give to the plant.

Smaller ferns sometimes have long rhizomes, which can form mats even with different species. So they must be carefully distinguished. With larger ferns it is important to collect and dry all the most significant features, even if some will be cut into pieces. It is important to make a note or a picture of all the aspects, which cannot be seen in the collected parts.

b. Bryophytes:

These small non-vascular plants include mosses (Musci), liverworts (Hepaticae) and hornworts (Anthocerotae). Their life cycle includes a long-lived green phase (gametophyte, which reproduces sexually) and a short-lived sporophyte, which reproduces by spores.

It is better to collect them into paper envelopes and to avoid polythene [plastic], which can badly interact with humidity. To find many interesting species, one must look in particular habitats like rocks, trunks, soil and other plants, remembering to carry a magnifying glass. During drying, which should be begun quickly, one must be careful not to overcook the specimen if heat is used.

c. Fungi and Lichens:

For collecting fungi it is better to use a basket along with paper to keep the specimens separated. Only fresh specimens in good conditions should be collected. It is possible to pick many specimens of the same species if they show different development stages. One must always look carefully before picking a fungus to detect the presence of parts hidden in the soil (pick them up too) and take a note of the habitat.

If the fungus is parasitic, one must look where it grew. Besides, some relevant characteristics could be changed after collection of the specimen. Hence it is very important to observe whether colour changes occur and note whether there is presence of latex, the consistency, the odour and so on.

An interesting feature to add to the collection is the spore print, which is done leaving the specimen overnight with its hymeneal surface downwards onto a white sheet of paper. A quick drying must soon follow, keeping the specimens at a temperature of approximately 40° C, avoiding lower temperatures and dampness.

Larger fungi should be cut in two or more parts to allow drying. Before placing the fungi in the herbarium it is better to leave them in a freezer for two days, to kill any insects or eggs. The specimens, if not particularly fragile, can be kept in paper envelopes (18 x 12 cm or less) with their data and then glued to standard herbarium sheets.

The delicate species, as many fungi are, should be placed in a small cardboard box (approx. 7.5 x 4.5 x 1 cm) within the paper packets. Lichens should not be pressed and, once dry, they must be placed in packets on sheets with their data.

d. Ancillary Collections:

The preservation of plants (or parts of them) in liquid medium allow the maintenance of the natural three dimensional aspect of the specimen. Hence various techniques have been developed to keep plants in spirit. Some groups like orchids or succulents are always better kept in spirit rather than on mounting sheet.

Different preservative liquids can be formed using alcohol, formalin or other components, which can be rather dangerous to handle. The Kew preservative is a mixture of 53% industrial methylated spirit (i.e. ethanol + 2-4% methanol + 9% water), 37% water 5% formalin solution in water and 5% glycerol. The glass jars for the ancillary collection can range from 70 to 3000 cc and they must have wide necks.