Herbarium methodology-collection and preservation of plant specimens, World and Indian herbaria

Herbarium methodology-collection and preservation of plant specimens, World and Indian herbaria:-

Herbarium:- A Herbarium is defined as a collection of plants that usually have been dried, pressed, preserved on sheets and arranged according to any accepted system of classification for future reference

and study.

Methods of preparation of herbarium specimens:- The preparation of a herbarium involves: 

1. Field visits and collection of specimens 

2. Pressing and drying

3. Mounting on a herbarium sheet

4. Preservation

5. Labeling

6. Storage

1. Field visits and specimen collection:- A complete specimen should possesses all parts including root system, flowers and fruits. Therefore, regular field visits are necessary to obtain information at every stage of growth and reproduction of a plant species. In the fields, the tools required are mainly trowel (digger) for digging roots, scissors and knife for cutting twigs, a stick with a hook for collection of parts of tall trees, a field note book, polythene bag, old newspaper and magazines. To avoid damage

during transportation and preservation many replicates of the specimens should be collected. The

collected specimen must be tagged with a field number and necessary information should be

recorded in a field note book.

2. Pressing and drying:- The specimens are spread out between the folds of old newspapers or blotting sheets avoiding overlapping of parts. The larger specimen may’ folded in ‘N’ or’ W’ or ‘V’ shapes. The blotting sheets with plant specimen should be placed in the plant press for drying. After 24 to 48 hrs the

press is opened.

3. Mounting:- The dried specimens are mounted on herbarium sheets of standard size (41 x 29 cm). Mounting is done with die help of glue, adhesive or cello-tape. The bulky plant parts like dry fruits seeds, cones etc. are dried without pressing and are put in small envelops called fragment packets.

Succulent plants are not mounted on herbarium sheets but are collected in 4% formalin or FAA

(Formalin Acetic Alcohol).

4. Preservation:- The mounted specimens are sprayed with fungicides like 2% solution of mercuric chloride.

5. Labelling:- A label is pasted or printed on the lower right hand corner. The label should indicate the

information about the locality, altitude, habit, date and lime of collection, name of collector, common name, complete scientific name etc.

6. Storage:- Properly dried, pressed and identified plant specimens are placed in thin paper folds (specimen covers) which are kept together in thicker paper folders genus overs), and finally they are incorporated into the herbarium cupboards in their proper position according to a well known system of classification. In India Bentham and Hooker’s system of classification is used for’ his purpose. Type specimens are generally stored in separate and safe places.

Functions and importance of Herbarium:- A modern herbarium serves numerous valuable functions. Some of the important functions of herbaria are as follows:

i. 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.

ii. 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. Thus, a herbaria provide data for botanical, ethno-botanical and phytogeographical studies.

iii. 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.

iv. 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.

v. The specimens in the herbaria are also used as a source of material for anatomical, palynological and chemo-taxonomical studies.

vi. 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.

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

World and Indian herbaria:-