HERBARIUM TECHNIQUES

Give any two uses of herbarium
1. Herbarium is a store of reference materials hence adequate arrangement for preservation of specimens and simple form of indexing should be put in place so as to enable them to be retrieved easily
2. Herbarium serves as a means of identification , these is done by matching unnamed plant with the named specimen in the collection or by conforming to identification arrived at by using botanical keys
Name any four habitats where collection of plant specimens for herbarium are done

Plants specimens are collected from; Ponds, Arboterioum ,Botanical gardens , Forest.

Identify any four equipment’s used in plant collection for herbarium specimens

Basic equipment

Waterproof field notebook to record habitat and location information.
Soft lead pencils for writing in rain.
Topographic maps and location information should include locations or latitudes and longitudes.
Small altimeter for measuring elevations.
Gardening gloves to prevent injury when handling irritating or thorny specimens.
Strong plastic bags for storing branches or carrying individually bagged collections; 18 -41 cm (4-6 mil) is adequate for most plant material.
Waterproof tags and permanent felt markers.
A shovel, trowel, or dandelion tool for digging underground stems, bulbs, corms, and roots.
Pruning shears or secateurs to cut plant parts (e.g., fruit, cones, flowers, buds, leaves, bark) or for trimming large, woody plants to appropriate size.
Paper lunch bags for storing cones

For aquatic specimens

A long, lightweight pole (telescoping if possible) with numerous prongs at one end, or a leaf rake with retractable prongs, or a long-handled cultivator.
Plastic food containers with lids, or zipper bags.
Snorkelling or scuba-diving equipment (useful if circumstances permit).
A white plastic slate with wax marking pencil for recording data underwater.

Identify the field notes that accompany specimens for herbarium collection

Date of collection
Name(s) of collector(s)
Location information
Habitat information
Aspect eg the exposure or orientation of the slope; measure using a compass bearing (remember to allow for magnetic declination).
Associated vegetation: a short list of other dominant species in the plant community being sampled.
Biogeoclimatic zone/subzone: zone, subzone and, if possible, site series.
Soil: type of soil encountered.
Moisture regime: the degree of wetness or dryness (xeric, mesic, hygric, hydric).
Water depth: for aquatic plants,
Note any flower or leaf fragrances, or any distinctive odors when the plant is bruised
The height and growth form (i.e., spreading, scraggly, columnar) may help distinguish between species of the same genus. This information is essential when the whole plant is not collected.
Flower and fruit colour for flowering trees or shrubs

Describe how herbarium specimens are mounted for permanent filling

Before starting, have ready acid-free mounting paper, cardboard sheets, glue in small, flexible, plastic squirt bottles, wooden spacer blocks, weights, needle and linen thread (optional), paper seed envelopes (Kraft coin envelopes), and identified specimens with completed acid-free label.
Wear appropriate PPE; mounting can be a very messy business.
Arrange supplies so the work can proceed in sequence, from left to right, or vice versa.
Place the specimens to be mounted at one end of the table, with a garbage can nearby ready for waste plants or dirt.
Glue the label to the bottom right corner of the herbarium sheet.
Annotation or determinavit labels, if present, should be placed directly above or to the left of the main label. If they are too far apart, the incorrect identification on the main label may be used because the smaller annotation label is not noticed.
Run a bead of glue only along the top edge of the label. Field labels or other information can be folded and affixed underneath. Make a note on the label if any extra information is glued under the herbarium label (e.g., additional information beneath). These should be rotated in location so you don’t end up with a bulge on a stack.
Leave space on the sheet for seed and fragment packets and for accession stamp/number—usually near the upper edge.
Remove any soil clinging to the roots or stems. Gently crush with the blunt end of the probe, rub the roots between your fingers over the garbage can, or lay on a flat surface and tease with a dissecting probe.
Use scissors or pruning shears to trim large specimens to fit the sheets.
Make sure that important parts are not cut off.
Sometimes the last particles can be dislodged by tapping the root gently on the inside of the garbage container. Try this only on robust specimens,as it will damage others.
Place a sheet of mounting paper on a cardboard sheet. The cardboard makes it easier to move the finished product and stack it for drying.
Arrange the plants on the mounting paper.
Vary the arrangement of specimens on the sheet to avoid otherwise sloping stacks that will cause problems in storage (brittle plants will break under lopsided conditions).
Salvage any valuable loose material, such as seeds or flowers, and place them in paper or wax paper packets (see Figure 6 for folding method).
Glue fragment packets near the upper edge or sides of the sheet after the specimens are mounted.
Avoid placing anything right at the edge of the mounting sheet, as it may stick out and get damaged. Leave approximately one and a half inches around sides for ‘‘finger space’’ to allow the sheet to be picked up without damaging the specimen.
Hold the specimen down with weights, such as plastic-coated lead bars or large metal washers, until the glue dries. You can dip the washers in acrylic floor wax before using.
Attach the specimen to the mounting paper with thin ribbons of glue running from the paper across the plant part to the paper .The glue should not cover any parts necessary for identification, for example, the nodes and ligules of grass

Describe herbarium preparation with respect to;
1. labeling

Each specimen collected should be labeled and the labels should contain the following information
the flora
the scientific name
Vernacular name
Local name
Locality
Longitude and altitudes
Habitat
Description of the plant characteristic
Economic importance of the plant
Frequency – the seasons when is the plant common
The collectors name

Cataloguing

The final step before filing the mounted or packaged collections in the herbarium is to assign accession numbers and to record the specific associated data in a computer-based file or an accession book. The amount of information recorded varies, but the more information you record, the more valuable the specimen is for future researchers.
These records become the index for the herbarium collection. In some larger, more progressive institutions, the labelling program serves a dual purpose, and accession numbers are assigned and recorded automatically when the labels are produced. This system saves time in a large collection. An accession book is adequate for a small collection. Accession numbers are assigned chronologically as specimens arrive, for example, starting with number 000001.

Storage

Once specimens have been identified, mounted, labelled, and accessioned, they should be frozen at −20°C for 48 hours to kill insects, then stored in cabinets in a specially equipped room called a herbarium. Specimens could also be frozen if they have been sitting out for a while during any of the above stages. Plant specimens, properly stored and handled, can be kept for a hundred years or more. Most herbaria store specimens on shelves in sealed metal cabinets (wooden cabinets may harbour insects).Proper storage involves the organization, handling, and maintenance of the collection. In all instances, the sheets should be enclosed in labelled MO type 1/2 inch double-score genus covers and a species cover with the genus cover

Describe pressing process in a herbarium

The pressing process in a herbarium is a critical step in preserving plant specimens for scientific study and documentation. Here’s a description of the pressing process:

Collection: Botanists or field researchers collect plant specimens from various locations, ensuring that they represent a diverse range of species. The specimens are carefully chosen based on specific criteria, such as their rarity, uniqueness, or relevance to a particular study.
Preparation: Before pressing, the collected plant specimens need to be prepared. This typically involves removing excess soil, trimming the roots, and selecting healthy and representative parts of the plant, including leaves, flowers, fruits, stems, or any other relevant structures.
Labeling: Each specimen is assigned a unique identifier or accession number, which is recorded on a label. The label contains essential information such as the scientific name, location, date of collection, collector’s name, and other relevant details. These labels ensure proper identification and traceability of the specimens.
Pressing: The actual pressing process involves flattening the plant specimens to preserve their shape and characteristics. Typically, botanists use specially designed plant presses for this purpose. A plant press consists of wooden or metal frames with straps or screws that can be tightened to apply pressure evenly.

Layering: To begin the pressing, the prepared plant specimen is placed between sheets of absorbent blotting paper or newspaper. The blotting paper helps in absorbing excess moisture from the plant and aids in drying. The plant specimen is positioned in a way that showcases its key features and allows for identification.
Stacking: Multiple specimens are stacked on top of each other in the plant press, separated by layers of blotting paper. The number of specimens that can be stacked depends on the size and capacity of the press. It is important to avoid overcrowding to ensure proper airflow and drying.

iii. Compression: Once the specimens are layered in the press, pressure is applied by tightening the straps or screws. The initial pressure is gentle to avoid damaging delicate structures. Over time, the pressure can be gradually increased to ensure thorough drying and flattening of the specimens.

Drying: The pressed specimens are left to dry in the plant press for a period of time, usually several weeks to months, depending on the thickness and moisture content of the plant material. This process removes moisture, preventing decay and the growth of fungi or mold that could damage the specimens.
Mounting: After the specimens are completely dry, they are carefully removed from the press. They may be trimmed to the desired size or shape for mounting. The plant specimens are then glued onto acid-free mounting paper or cardstock using archival-quality glue or adhesive strips. The mounting paper often contains pre-printed grids or ruled lines to aid in measurements and observations.
Labeling and Storage: Once the specimens are mounted, they are labeled again with the unique identifier, scientific name, and other relevant information. The mounted specimens are stored in protective folders or archival boxes to safeguard them from damage, dust, and pests. Proper storage conditions, such as controlled temperature and humidity, are maintained to ensure long-term preservation.

The pressing process in a herbarium is crucial for creating a permanent record of plant biodiversity, facilitating taxonomic studies, and contributing to scientific research, conservation efforts, and education.

State the information included in a herbarium specimen label

Labels should contain the following information
The flora
the scientific name
Vernacular name
Local name
Locality
Longitude and altitudes
Habitat
Description of the plant characteristic
Economic importance of the plant
Frequency – the seasons when is the plant common
The collectors name

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