Taxonomy assignment

PRESENTED BY DEEPAK YADAVMASTER OF SCIENCE-M.SC

HERBARIUM THEIR IMPORTANCE & ITS APPLICATION

UNDER SUPERVISION OF PROF SATYA NARAIN

INTRODUCTION A HERBARIUM is a collection of dried plants systematically

named and arranged for ready reference and study. To make a herbarium specimen, the plant is collected, and notes are made about it.

The plant is then pressed until dry between blotters that absorb moisture and mounted onto a herbarium sheet with a suitable label.

Herbarium which has over 5,000,000 specimens and the New York Botanical Garden with over 7,000,000 specimens.

“There is special need of [herbarium] material of cultivated plants" . [A herbarium] is like a reference library and it enables a nurseryman to keep his stock true to name" (2). Collectors should learn to make excellent specimens, and there are reasons why excellent specimens are needed. A herbarium is a "Hortus siccus" or "dry garden" and is used for study by botanists and students; they want as good material as possible to study. Plants are often collected in far-off places and sent thousands of miles away from where collected to be studied and correctly named.

INTRODUCTION continued Such a study may be carried on many years later

than when the collection was made so that the best kind of dried plants are necessary. The collector in the field should make note of many details that will be unknown to the botanist who studies the plant, especially describing characteristics that vanish during drying.

"New species should be described only from good collections. Many a collector has not had his name associated with a species which he was the first to collect because his specimens were poorly prepared“.

If a person has a plant that he/she wants named by a competent botanist, it is only fair to the botanist to send him/her good dried material, and not just one or two leaves, as are sometimes sent to many herbaria, to be identified.

Historical background Sometime in the 1530’s Luca Ghini, who was at that

time Professor of Botany in the University of Bologna, Italy, discovered that plants dried under pressure and pasted on sheets of paper could be preserved almost indefinitely - and could be transported easily. It is on record that he had a collection of some 300 sheets so prepared. Unfortunately, it appears that this collection no longer exists.

Several of Ghini’s students and colleagues recognized the value of this technique and the collections of at least two of them survive. Andrea Cesalpini, the author of De Plantis Libri XVI, which is the basis for our consideration of flowers and fruits as the prime structures on which to base identification and classification, formed about 1563 a collection of some 768 specimens of Italian plants. This collection is still preserved at the Instituto Botanico of the University of Florence.

Ulisse Aldrovandi, who succeeded Ghini as Professor of Botany at Bologna and who taught a number of the most prominent botanists of the next generation, attempted to form an herbarium that was world-wide in scope. About 4,368 specimens of this collection are preserved at the Instituto Orto Botanico in Bologna.

The herbarium technique proved so useful that it was quickly adopted by botanists throughout Europe. Arber (10) records that more than 20 collections formed or begun before 1600 are still extant in various European herbaria.

Originally, the individual sheets with plants mounted on them were bound and treated as books. Aldrovandi’s herbarium, for example, is preserved as 17 bound volumes.

This was the general technique until about 1700. Linnaeus (1707-1778) did not use this technique, preferring to keep the sheets separate and storing them (probably in cases) horizontally. Stearn thinks that Linnaeus’ example and teaching led to the spread of this technique - which is the one generally used today.

Binding the single sheets into books had the disadvantage of making any changes or additions to that part of the collection difficult if not practically impossible.

This led to the use of portfolios, in which several unattached single sheets could be kept in a book-like fashion, a compromise between bound volumes and single sheets filed in cases. The advantage of portfolios was that they could be stored on shelves like books. The disadvantages were that the specimens were joggled every time the portfolios were moved and could be severely damaged by crushing if shelved too tightly. There was also always the risk of insect infestation, unless the specimens were poisoned - a messy and unpleasant, if not risky, business.

However, as late as 1833, Asa Gray was selling bound volumes of mounted grass and sedge specimens entitled North American Graminae and Cyperaceae. And even today biological supply houses sell portfolios in which to keep herbarium specimens. Old techniques die slowly.

Plant collectingThe purposes of collecting, there are two main reasons for collecting plants: 1- To obtain records and specimens of plants,

either for a personal collection or to be stored in a herbarium. Properly run herbaria where specimens are suitably stored and catalogued have great scientific value.

2- The major reason for plant collecting is in order to later identify an unknown specimen encountered during fieldwork. Often these specimens consist of small, atypical plants with no flowering or fruiting parts. As herbarium specimens they are often next to useless.

What to look for in a specimen

Specimens for collection should be as complete as possible. Ideally flowers and fruit should be included, as well as vegetative parts. Clearly, in most cases, this is impossible since ripe fruit and flowers do not usually occur at the same time. Often, however, remains of growth from the previous year can be found at the base of the plant or on another specimen nearby. Only collect fruits or seeds if you are certain that they belong to the same plant or the same species.

Specimens should be typical and healthy, with at least some fully expanded leaves where possible. Avoid taking diminutive individuals because they fit into a press more easily or are easier to reach. Take the plant from its typical habitat. If a species normally grows in woodland, do not collect specimens growing by the roadside or in a clearing. Sometimes leaf shape, flower Color and other characters are completely altered on plants growing in full sunlight.

What to collect The whole of small vascular plants should be collected including

the underground portion. Roots, trailing or underground stems and storage organs are often helpful (and sometimes essential) in identifying specimens. A strong knife or small trowel is helpful for digging out a plant. Excess soil can be shaken off, or washed off carefully if water is available.

When taking the whole plant is out of the question, specimens containing all essential features (all leaf types, twigs, flowers, fruits and so on) must be cut from the plant. If the species is a large herb such as a thistle, the specimen should include basal leaves as well as enough stem to show the range of stem leaves and flowering and fruiting material.

Shrubs and old and new twigs, buds where possible and fruit and/or flowers. If lower and upper leaves are different, or there is significant variation between a shaded and unshaded side of a tree, then collections should be made from both. To minimize damage to parent trees and to specimens, twigs should always be cut off cleanly with a sharp knife or pruners. Breaking the twig can strip the bark and ruin a specimen or cause unnecessary harm to the tree or shrub from which it was taken.

Notes to take Every specimen should be accompanied by comprehensive notes retained in a collecting note

book. These notes may not only aid in identification of the material, but will later be used to complete the information on the herbarium label.

1) Collection number: This is a serial number specific to a collector and a specimen. The number may start at 1 and continue through the collector's life time.

2) The name of the plant: This is important as it helps the collector remember the individual specimen even if the labels are accidentally lost or mixed. Even if the collector has no idea what the specimen is, it is sometimes useful to give a completely arbitrary name such as "Lacy Moss" or "Big Leaf". This has a double advantage in vegetation surveys in that this name can then be applied to other specimens of them same species if they are encountered before the material has been identified. This way there is no need to collect the plant more than once or try to remember if it is "Unknown #1" or "Unknown #2"

3) Locality: This should be as detailed as possible, including the name of towns, roads akes and so on in the vicinity, as well as Township, County or District. The latitude and longitude or the UTM Grid Reference and Map Number are also important.

4) Description: This should include everything about the plant that is not obvious on the herbarium specimen. Essential items are the height, type of bark, whether the stem is upright, sprawling or drooping, and obvious smells, whether the plant is clumped, single or growing in patches and the presence of creeping or underground stems. Flower and fruit Color should also be noted as these often fade on dried specimens.

5) Habitat: This should include the general habitat as well as more specific details of micro-habitat. Important points are type of soil or other substrate (sand, clay, granite, dead wood, other vegetation), associated species, moisture and aspect (fully exposed on a south facing bank; in a damp hollow under dense scrub, etc). The more careful and detailed such notes are the more useful they become.

6) Date. 7) Names of collector(s). 8) Notes: Space should be left to note the name of the person who makes the final

determination (identification), the date on which it is made and the place were the specimen is sent or stored. The receiving herbarium will add their own accession number to the specimen.

ProcedurePressing and drying vascular plants The most important thing to do with

freshly collected material is to dry it out as fast as possible. This prevents fungal infections and preserves Colour .

Vascular plants must be pressed and dried as soon as possible after they are collected.

Usually this means that plants should be pressed the day they are collected. It is an important aspect of plant collecting that enough time be left at the end of the day to process the specimens. If this includes identification, this stage may be quite slow.

When plants have to be left overnight they should be put in a cool place. Sometimes woody specimens can be placed in water for a day or so to force buds or restore wilting leaves.

The plant press The plant press is designed so that plants can be dried quickly

while being pressed flat. It consists of two cross-slatted wooded frames about the size of a folded newspaper.

Plant specimens are laid in folded newspaper between layers of blotter, foam sheets and corrugated cardboard. The newspaper provides a folder for the plant. The paper, blotter and foam draw the moisture away from the specimen.

The cardboard allows air circulation within the press to speeds up the drying process, and helps keep the specimens flat. Plants in their newspaper folders are piled in layers of alternating padding and cardboard on one of the wooden frames.

When laying out of the specimens is complete, the second frame is laid on top of the pile which is compressed and strapped as tightly as possible with two adjustable straps. Standing on the press while you fasten the straps helps get them properly tight. The press is then placed to dry in warm (not hot), dry, circulating air.

After 24 hours the paper and blotters should be changed to enhance the drying process.

The straps have to be tightened periodically as the plant material shrinks. After this, the specimens may be left undisturbed for several months or weeks until they are completely dry. Often the press will be emptied soon after the specimens are dry, so that the card, blotters and foam can be reused. Dried specimens can be stored and transported in their newspaper folders in a cardboard carton.

Herbaria have special drying cabinets in which the presses are dried. In the field drying is not so easy, but it should have priority as specimens are easily ruined if they remain damp. A press left upright on a rock, or kept on a car roof rack, where air can circulate will dry much faster than one left lying in a tent, vehicle or room.

Laying out the specimens for pressing

Two important points should be borne in mind when plants are prepared for the press. i) the dried specimen should fit neatly onto a standard herbarium sheet and ii) As many features as possible should be visible on the mounted specimen. If a specimen is too tall to fit in the press or on the herbarium sheet, make a zig-zag

bend in the stem or cut and produce sheet of 1/3, 2/3 & 3/3. This shortens the effective length of the specimen without any of the material being lost. Plants with many long, narrow leaves such as grasses will bend and press more neatly if a piece of paper with a slit in it is placed over the elbow of the bend to hold all the leaves together.

Too many leaves on a herbarium sheet look untidy and can obscure detail. Where it can be done without destroying information, snip off some of the leaves, but ALWAYS leave part of the petiole so that it is evident that leaves have been removed.

When stems are very thick they can be sliced lengthwise so that they are less bulky. Leaves of plants with thick stems do not always get sufficiently pressed and may tend to wrinkle. The end of woody stems should be sliced diagonally so that the color of the wood and pith are displayed.

Leaves or petals which have wilted, or are folded over, will not always lie flat for pressing. A piece of wet newspaper will "stick" them in place. By the time the newspaper is dry the leaf will have stabilized and cause no more trouble. On every mount, the back of at least one leaf should always be visible. Sometimes this involves twisting a petiole to obtain the desired effect. If there are several flowers on a specimen, some should always be pressed open and flat so that the inside is displayed. This can usually be achieved by careful, deliberate pressure with the thumb before the newspaper is folded shut.

Loose seeds and fruit can be placed in a small paper packet and pressed with the specimen. Later this packet will be glued to the herbarium sheet. Some conifers loose most of their needles on dried specimens. Once the material is dried, the needles can be shaken off and placed in a packet.

Once plants are pressed, changing the paper after the first 24 hours not only enhances drying, but allows the collector to make cosmetic adjustments to the specimen while it is still supple.

Dried separately

Mounted together

Do not fold up basal lobes.

Can not see base.

Can not see apex.

One sideremoved. Mid rib.

Multiple sheets.

Once all the herbarium specimens dried the

next step will be followed sorting of duplicates

Mounting specimens Mounting is the process of affixing a dried pressed plant and its label to a

sheet of heavy paper. This provides physical support that allows the specimen to be handled and stored with a minimum of damage.

Prior to attachment, the specimen and its label are laid out on the paper to allow maximum observation of diagnostic (usually reproductive) features as well as the range of variation in vegetative structures, including both sides of the leaves.

Plants are generally positioned in a life-like arrangement (that is, with roots or lower stem toward the bottom of the sheet and flowers toward the top). When laying out the plant, be sure to leave space on the sheet for the specimen label, annotation labels, and institutional accession seal.

A paper envelope or packet should also be attached to the sheet to contain any fragments of the specimen that break off over time. Once the optimum arrangement of the specimen has been determined, it is attached to the sheet using a combination of glue and strips of gummed linen cloth tape.

Glue is used sparingly to attach the larger portions of the plant, such as stems, large leaves, and fruits. Gummed linen mounting strips are then applied to reinforce portions of the plant that might be torn loose as the specimen is used. Large or bulky items may need to be sewn onto the sheet with a sturdy linen thread.

The objective is to secure the specimen firmly to the mounting paper, while leaving some pieces of the plant loose enough to be removed if necessary.

The best way to learn proper mounting procedures are through hands-on training and practice with a variety of plant specimens. Because herbarium specimens are intended for long-term study and storage, it is critical that that all supplies used for mounting be both durable and archival. Archival denotes materials that are free of acids and other compounds that may cause them or the specimen to degrade or discolor over time.

PHOTO SEQUENCE OF SPATULA & NEEDLE METHOD

Herbarium sheet training aid showing specimen label location, possible packet locations, annotation label(s) location, desired edge space and resulting available mounting space.

Basic tools: scissor (used only for cuttinggummed label tape; never to be used onplant specimen!), spatula, needle(angled), forceps, creasing tool (bone),Sharpie(fine point), sponge typeeraser, and gummed linen tape. Stampedherbarium paper and specimen-paper(newspaper) with plant’s scientific nameand collection number (lower edge).

Some additional basic equipment: written mounting standards, metal washers (weights), archival glue (polyvinyl alcohol), wooden blocks, sponge type eraser, packet, towels, forceps, needle (angled),

spatula, specimen label, plant specimen in newspaper, and herbarium sheet on cardboard backing sheet.

Orienting a plant specimen by arranging the plant to display its prominent features andmaking it fit within the available mountingspace.

Gluing the plant specimen using the spatula and angled needle; the needle is used to lift the plant part while the spatula applies asmall amount of glue under the plant part.

Having completed the gluing of the plant specimen and applying metal washers as weights during the gluing process to ensure sufficient contact with the herbarium sheet,

wooden blocks are then placed on each corner (more if needed), to allow stacking while drying and saving space.Stack of plant specimens drying,

with wooden blocks used to separate each plant specimen/cardboard sheet, preventing herbariumsheets from sticking to each otherand also saving space.The “FLIP-OVER” test being conductedby simply holding the plant specimenalong with the cardboard backing sheetand turning both completely over(spread fingers) and observing if anyplant parts hang down; touch up withglue and spatula/needle as necessary.

The completed herbarium plant specimen

Herbarium and its importance

A herbarium (plural: herbaria) – sometimes known by the 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.

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.

Uses of herbariumHerbaria 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 EnglandSpecimens 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.

Largest herbaria

The Swedish Museum of Natural History (S)

Many universities, museums, and botanical gardens maintain herbaria. Herbaria have also proven very useful as sources of plant DNA for use in taxonomy and molecular systematics. The largest herbaria in the world, in approximate order of decreasing size, are:

•1Muséum National d'Histoire Naturelle (P) (Paris, France)•2New York Botanical Garden (NY) (Bronx, New York, USA)•3Komarov Botanical Institute (LE) (St. Petersburg, Russia)•4Royal Botanic Gardens (K) (Kew, England, UK)•5Conservatoire et Jardin botaniques de la Ville de Genève (G) (Geneva, Switzerland)•6Missouri Botanical Garden (MO) (St. Louis, Missouri, USA)•7British Museum of Natural History (BM) (London, England, UK)•8Harvard University (HUH) (Cambridge, Massachusetts, USA)

• 9Museum of Natural History of Vienna (W) (Vienna, Austria)•10Swedish Museum of Natural History (S) (Stockholm, Sweden)

•11United States National Herbarium (Smithsonian Institution) (US) (Washington, DC, USA)•12Nationaal Herbarium Nederland (L) (Leiden, Netherlands)•13Université Montpellier (MPU) (Montpellier, France)•14Université Claude Bernard (LY) (Villeurbane Cedex, France)•15Herbarium Universitatis Florentinae (FI) (Florence, Italy)•16National Botanic Garden of Belgium (BR) (Meise, Belgium)•17University of Helsinki (H) (Helsinki, Finland)•18Botanischer Garten und Botanisches Museum Berlin-Dahlem, Zentraleinrichtung der Freien Universität Berlin (B) (Berlin, Germany)•19The Field Museum (F) (Chicago, Illinois, USA)

•20University of Copenhagen (C) (Copenhagen, Denmark)•21Chinese National Herbarium, (Chinese Academy of Sciences) (PE) (Beijing, People's Republic of China)

The importance of herbaria.

The sheets from herbaria have more than taxonomic importance. They have been used to look at aspects of physiological ecology. As mentioned, specimens taken from the Cambridge herbarium have been used to examine how stomatal frequency has changed over the last 150 years.The leaves of native trees in South East England now have 40% less stomatal pores than those collected at the turn of the Nineteenth Century. This seems to be a response to changing levels of carbon dioxide.

Detailed records and maps of the distribution of species over time can also be valuable in understanding how our flora is changing, the impact of invasive species and the possible effects of changing climate.

In England, the potato began to be used more widely as a crop when it received (in 1662) an endorsement from the Royal Society, which suggested that the planting of potatoes would help prevent / offset famine. There have been two main hypotheses as to the geographical origin of the European potato; one holds that it came from the Andes whereas the other suggests a lowland Chilean origin.

Analysis of the material (which dates from 1600 to 1910) from the various herbaria indicates that the Andean potato was grown into the 1700’s, but the Chilean form came to dominate in early C19th (through further introductions).

The paper by Ames and Spooner (American Journal of Botany, 2008, 95(2): p 252- 257) is another demonstration of the importance of herbaria and their specimens in terms of the analysis of the origin of our modern crops and their various cultivars.

Professor David Mabberley, former keeper * of the Herbarium, Library, Art and Archives at Kew said in a recent interview: “The purpose [of a herbarium] is as a record of plants, in particular places, at particular times.” Herbaria enable scientists to create a map (in time and space) of the genetic distribution of plant material across the world, allowing them at times to reconstitute damaged ecosystems; and sometimes find relatives of ‘staple crops’ that have disease resistance.