Unfortunately, many or most herbaria throughout the United States have
recently experienced significant neglect. Biology and botany programs have
slowly discontinued taxonomic and organismal aspects of their curricula, and
molecular and cellular emphasis has created a gross academic imbalance.
Faculty specializing in taxonomy and natural history are not being replaced.
The result has been not only the deterioration of important natural history
collections, but an attitude has developed among many modern scientists
who look at organismal biology as an outdated discipline that has no
potential to contribute to science or society. This naive arrogance threatens
the knowledge-base needed to train new scientists to identify organisms and
understand their life histories and autecology. The fact of the matter is that
there is a great need for organismal biologists and their collections. As
habitat is lost to development, trained field biologists are needed to assess
the impact of proposed development projects on local and regional
biodiversity. On a larger scale, natural history collections represent a
means to measure the change in the distribution and range of species as a
result of climate change and anthropogenic disturbances (which may include
climate change). Molecular biologists and geneticists will find that properly
preserved and maintained collections facilitate a whole range of studies on
both spatial and temporal scales. The short sightedness of individuals who
view herbaria and other types of natural history collections as worthless
antiquities precludes the use of such repositories for modern applications.
HERBARIUM [hûr•bâr'î•ûm] noun, plural herbaria (from the Latin term herba = plant, and arium = a container
or facility. 1) a collection of dried plants, usually mounted and classified; 2) the room or building where a
dried plant collection is kept. Fungi and fungi-like protists have traditionally been classified as plants, so
collections of these organisms are still called herbaria. The proper noun Herbarium as used in this
publication refers to the Swinehart Herbarium as a collection (as in definition 1).
The Mission of the Swinehart Herbarium
1. Provide a source of data for comparative studies of the relationships among plant groups, their patterns of
variation, their evolution, and their ecology & geographic distribution.
2. Serve as a repository for research specimens that can be studied and verified by future investigators.
3. Provide reference for the precise identification of specimens.
4. Serve as an educational resource for undergraduate and graduate instruction in the botanical sciences.
5. To be a careful steward of the collection so that both existing and presently undiscovered applications will
be feasible in the future.
"From a scholarly point of view, an herbarium is its own excuse for being, not only as a collection of plants
that once lived, but as an edifice built by the curiosity and care of hundreds of individuals. In some ways, the
collections resemble those ancient churches in Sicily, where the Greek columns were joined by Roman
arches, toped with Sarracen domes, and finished with baroque facades. Like such churches, an herbarium
summarizes history. It records the human effort to penetrate the mysteries of nature, and the attempts of
individuals to construct from apparent chaos an orderly system of thought"
-Jeanne W. Halpern
Vascular plant specimens in the Swinehart Herbarium follow the standard format, where pressed plants of a
given individual (whole or in part) are taped or glued to an herbarium sheet(s) having a standard size of 16.5
x 11.5 inches (except for the xylarium where wood specimens stand alone and are labeled directly on the
specimen; or spirit collections which are in jars with liquid ethanol of formalin preservatives). Specimen labels
are attached to the lower right corner of the sheet. Loose parts such as seeds, or fragments of vegetative
and reproductive parts may be included in envelopes attached to the sheet.
Bryophytes are placed loosely (not attached) in standard bryophyte envelopes, and these envelopes are
attached to an herbarium sheet by staples. Several specimens of a given taxon may be mounted on the
same sheet to save space. Sometimes sheets will include specimens of a taxon that are all from a similar
locality, all specimens from a given county for instance.
Many algae are probably best stored in spirit collections (preferably 60% ethanol with a small amount of
Glycerine added to prevent desiccation). Some of the macro algae can be “floated” onto an herbarium sheet
in a pan of water to maintain aquatic habit. Otherwise, the filaments become clumped into amorphous clods.
Fungi (including lichens) are curated much like bryophytes when possible, however, large and voluminous
specimens require that they be placed in appropriately sized boxes. These boxes are labeled and stored in a
separate place in the herbarium. Blank sheets indicating the presence of a boxed specimen stored
elsewhere may be placed with the mounted specimens. Some fungi are best kept in spirits to prevent loss of
gross morphology as a result of drying.
Arrangement of Specimens. Folders in the Swinehart Herbarium are arranged alphabetically by family,
then genus, and specimens within a genus folder are arranged alphabetically by species. This facilitates
easy access for a research collection, although many herbaria organize their specimens phylogenetically.
Accession Numbers & Records. Accession numbers are assigned to each specimen, much like library
books have accession numbers, and in the Swinehart Herbarium, they begin at No. 1. New accessions are
recorded by hand with an ink pen in a record book with all appropriate data. Additionally, all the data in the
record book are entered into a computer database comprised of numerous fields that allow searches by date
of collection, date of entry, genus, species, family, location, etc.
Restoration of Damaged or Deteriorated Specimens. Even some of the more recently collected
specimens need work due to handling, etc. The policy established for the Swinehart Herbarium has been to
give attention to restoration of specimens on a situational basis. In other words, when a folder is pulled, for
whatever reason, specimens needing restoration are attended at that time.
Acid-based paper. Most of the specimens in the Swinehart Herbarium
have been mounted on acid-free paper. However, some specimens received from gifts and exchanges are
mounted on acid-based paper. The acid used in the paper-making process can result in the disintegration of
the cellulose fibers that make up the matrix of the paper. The acid can also migrate from paper to specimen
and cause deterioration of the specimen. There is need for concern not only for individual specimens, but
also other specimens stored in the same folder, because acid can leach from page to page. Evidence of acid
deterioration includes yellowing, blackening, and brittleness/fragmentation. Sheets showing significant
symptoms of acid deterioration should be remounted. This is done in one of two ways. If the plant is
attached by tape, it can be removed from the old sheet, entirely, and remounted on new paper. If the
specimen is tenaciously bound to the paper by glue, as much of the old paper as possible can be cut away
and then the specimen and remaining paper can be glued to a new sheet. It is imperative that all labels and
any form of writing on the sheet be cut out and saved. These items can either be placed in a glasine
envelope and attached to the sheet, or they may be glued directly on the new sheet in the appropriate
places. To determine whether a new sheet is suitable for mounting (non-acid based), use a pH testing pen.
A color change to yellow indicates an acid reaction, a color change to blue or purple indicates a basic
Depauperate or inappropriate labels. Although all specimens collected and mounted by me have
standard labels, some specimens that end up in an herbarium from other sources may have labels of very
poor quality. They range from note-cards, to scraps of paper, to no label at all (scribble directly on the
sheet). If such labels are associated with a specimen slated for a new sheet, the old label should be cut off
and put in a glasine envelope (attached to sheet), and a new label should be attached. Generally, typeset or
printed labels from other individuals or herbaria are always appropriate, for example labels that say, Ex
Herbarium of Delzie Demaree or Herbarium of Indiana State Teachers College. Moreover, any label from an
historically significant collector or associated with an historically significant collection should not be removed
or tampered with unless in a necessary restoration.
Improperly attached specimens. It is always unfortunate to see a specimen in an herbarium that someone
has attached to a sheet with transparent tape used for gift wrapping. No matter how good the tape looks at
first, it is always destined to become an unattractive, useless, yellow scab on an otherwise worthy specimen.
It is embarrassing for the person responsible. The crime is furthered by putting the specimen in the
herbarium alongside more worthy counterparts. If a specimen is worth collecting, it is worth mounting and
labeling properly. Even standard herbarium-quality cloth tapes can become detached, thus requiring
adhesive. The good news is that most of these specimens can be restored by cutting the tape and removing
the specimen and attaching it to a new sheet using a good quality, reversible, white glue.
Loose parts. Fragmented plant remains are always a problem, especially with poorly mounted specimens.
Large, meaningful fragments such as leaves and reproductive structures are generally placed in glasine
envelopes and attached to the sheet. Sometimes, it is desirable to take very fragile fragments (that would
otherwise become broken in an envelope) and re-glue them to the sheet either in their original place prior to
breakage (if that can be determined) or on another area of the sheet.
Herbarium specimen showing fragment envelope
Discarding specimens. If the herbarium has been properly curated from its beginnings, the topic of
discarding specimens is moot. However, carelessness can result in worthless specimens working their way
into an herbarium. The primary consideration here is whether or not the curator should justify the space
(both physical and in terms of computer memory that these specimens occupy). Most literature on herbarium
curation including the excellent Herbarium Handbook by Bridson and Forman does not discuss the
“unthinkable” topic of discarding specimens. However, it is the opinion of the author that there are certain
instances when it is justifiable to discard a specimen, just as there are times when libraries discard books.
The following list outlines criteria for discarding specimens in the Swinehart Herbarium. They are meant to be
as conservative as appropriate for my herbarium. All of the criteria must be met before the specimen(s) can
1. The specimen has no date.
2. The specimen has absolutely no location data.
3. The specimen was not collected or identified by a reknowned or noteworthy collector.
5. The specimen is not particularly rare or infrequent in the natural world.
6. There are at least five specimens of the same taxon of the specimen in question already in the herbarium.
Procedures for discarding a specimen (once the above criteria have been met) are as follows.
1. Remove the specimen from the Herbarium.
2. Begin a notebook for discarded specimens.
3. Enter the accession number of the specimen and any information about the specimen in the notebook.
Include justification for discard.
4. If the specimen has been recorded in a “Record of Collections” and or on a computer database, make
note that the specimen has been discarded.
5. Discard the specimen.
STANDARD FORMS & LABELS
In many cases, the first impression that another institution has of an herbarium, is based on a letter or even
a specimen sent through the mail. Therefore, it is extremely important that the design of printed materials
reflect the high degree of excellence and professionalism that characterize the herbarium. The following
forms and labels have been established in an attempt to meet these standards.
Loan Forms. Loans of specimens from the Swinehart Herbarium to other institutions are accompanied by
three copies of a loan agreement that outline the terms of the loan and a list of the specimens being sent.
There are three copies of the loan form. One is for the records of the borrowing institution, one copy is to be
signed by the borrower and returned to the Swinehart Herbarium to inform me that the loan was received in
good order, and one copy is to be returned when the specimens are returned, and it will then be signed by
me and sent to the borrower as a return voucher.
Herbarium Specimen Labels. Perhaps the most important written document in the Herbarium is the
specimen label. Below is the label in current use for specimens in the Swinehart Herbarium.
Stamps. Regularly used, special stamps include:
Accession No.: This is the accession number of the specimen. It is stamped both within the Accession Label
on the lower left of a sheet and on the specimen label. While most herbaria do not include the accession
number on the specimen label, I have begun this practice because I have encountered situations where a
label gets detached and separated from the sheet due to failure in the adhesive over time. Having an
accession number on both the sheet and the label allows the label (and its important data) to be returned to
the proper sheet / specimen.
Accession Label: This label is stamped either on specimen envelopes (in the case of mosses) or on the
bottom left corner of vascular plant specimen sheets. The accession number of the respective specimen is
placed next to the herbarium acronym within the box.
Other stamps used in the Herbarium are the typical office type, including such things as “COPY”,
“RECEIVED”, “ORIGINAL”, “DUPLICATE”, etc.
PROCESSING PLANT SPECIMENS
Collecting New Specimens
Addition of specimens to the Swinehart Herbarium will involve plants associated with specific field studies as
well as plants collected simply to add to the diversity of the collection. Collections from field studies are
especially important. The flora of a local wetland for instance will tell future scientists much about natural
succession as well as human disturbance/destruction.
What and How to Collect. When a specimen is ready to be collected, several things need to be considered
before the “harvest.” First, is it legal and/or ethical to take a specimen of a given species in a given
location? Check with local laws about plant collecting on public and private land. Some species are
protected by law, and regardless of the status, all plants and other natural features are protected in State
Nature Preserves. Collecting permits are often granted for legitimate projects and requests. These may be
solicited by writing the State Department of Natural Resources. However, even when collecting is legal, the
collector must impose upon himself some personal standards. Some botanists will not take a specimen if less
than six are present in a local area. Thirty is perhaps a safer number. Other considerations include proximity
of similar sites with similar species, relative rarity of the plants, etc.
The next consideration is which plant to collect. Some botanists mistakenly collect the biggest and best of a
group. The problem with this practice is that instead of collecting a representative sample, an exceptional
specimen is taken. Regardless of whether an individual has an unusually good habit or an unusually bad
habit, it is still exceptional. Therefore, select an average specimen, representative of the group. Much is to
be gained from this practice, as herbarium specimens can be of use to more than just taxonomic botanists.
Plants damaged by fungi, insects, and other organisms tell much about the ecology of the system both
spatially and temporally. Whenever possible, collect reproductive structures, flowers and or fruits, and roots.
Once a plant has been selected, write down as much information about its situation as possible in a field
notebook. Assign a collection number to the plant (preferably with a string and tag) and then collect the
specimen. A trowel can be employed to acquire roots in addition to the obvious stem, leaves, and
reproductive parts. Not all herbarium specimens will have roots, while these are not ideal, they are still
worthwhile. Certainly, large, woody trees will not allow roots to be collected, but a carefully removed sample
of the bark is not difficult to take.
After the plant has been taken, it should be wrapped in moist newsprint and placed in a vasculum. A
vasculum is a rigid metal, cylindrical container with a shoulder strap. It protects the specimens from being
smashed, etc, and keeps them moist and unwilted. Some botanists use plastic bags to collect, but doing this
in a marsh dominated by swamp rose (Rosa palustris) or other shrubs will result in a trail of specimens
marking the path of a collector with a torn garbage sack.
Pressing. Fresh, unwilted specimens are ready for immediate pressing. Wilted specimens will need to be
soaked in water to soften the leaves and flowers. A press consists of blotters, newsprint, and supporting
pieces of cardboard, sandwiched between two hardwood latices. Plants are placed in a folded piece of
newsprint (preferably without ink, as this ink can rub-off on specimens) and arranged so that when flattened
and mounted, as many key features as possible will be exposed. Some leaves should be facing up, others
down. Tall specimens should be folded in an “N” shape to facilitate placement on a standard herbarium
sheet (some large specimens will need to be broken and glued to more than one sheet). Specimen data
should either be written on the newsprint, or included as a separate piece of paper with the plant. The
specimen, now in a piece of folded newsprint, is placed between two blotters. About 10 specimens with
blotters are sandwiched between pieces of cardboard (for support). As many as 50 plants, depending on
their thickness, may be pressed at once. After the specimens, blotters and cardboard inserts have been
placed between the wood lattices, the press is put under pressure by sitting on the apparatus and tightening
the two straps. Most plants dry within about a week. Changing of blotters may be necessary on the third day.
Processing New Specimens
Drying. Presses full of fresh plants can be placed into a drying cabinet which accelerates drying. Both
heaters and a fan contribute to the drying process. Presses should be set on end to facilitate escape of
water vapor. Avoid high temperatures, as this will cause browning of the specimens.
Decontamination. Eradication of prospective insect pests is conducted by deep-freezing the specimens.
This is done after drying. Freezing before drying may damage internal structures of a specimen by means of
ice-crystal formation. Most destructive insects in the herbarium are tropical, and all stages of their life cycles
succumb quickly to freezing. Dried plants should be frozen for at least 24 hours before placement in the
Herbarium. However, to insure that these and other pests do not endure and propagate in the herbarium,
paradichlorobenzene tablets (moth balls) are placed in containers in each cabinet. This is the pleasant,
familiar aroma that characterizes the Herbarium (note: paradichlorobenzine may have carcinogenic /
mutagenic qualities. Other pest deterrents may be desirable for some).
Types of Glue & Proper Application. Experience has shown that gluing specimens to the herbarium sheet
is superior to other methods of attachment, at least in terms of durability. Several types of glues have been
used in the past, but white glue has proven to be the best. Many herbaria use white wood glue, or the
“Elmers” type, however, the best type of white glues are made especially for mounting plants. Most of these
glues are flexible, water soluble, and reversible. The glue used by the Swinehart Herbarium is the Missouri
Botanical Garden Type. This is a white, plasticized PVC resin that does not become brittle with age. The
method of application is the “Glass Plate Method”. A quantity of glue is poured onto a plate of glass and an
appropriate amount of water is added to the glue to reduce the viscosity to roughly the consistency of maple
syrup. The glue is then spread out in a thin layer over the glass plate. At this point, an assembly line is
established in the following order: un-mounted specimens, glass plate, herbarium paper, cardboard support,
stacked supports with mounted specimens. The following procedure is conducted.
1. A specimen is removed from the newsprint folder and carefully placed on the glued plate (it is a good idea
to make sure the plant will fit the herbarium sheet before gluing).
2. All portions of the plant are gently pushed into the glue with tweezers.
3. The plant is carefully removed from the glass plate and placed on an herbarium sheet. Make absolutely
sure that there is enough room on the herbarium sheet in the lower right corner for the specimen label.
Labels must be FREE AND CLEAR from the specimen.
4. Place any seeds or other loose fragments in a glasine envelope and glue or staple the envelope to the
herbarium sheet, preferably above where the specimen label will be fixed.
5. Place the mounted specimen on the cardboard support.
6. Place several metal washers on the plant to assure attachment of the specimen to the paper.
7. Attach temporary label (scrap of paper with data) to the sheet with a paperclip.
8. Stack the cardboard supports/specimens (with wooden spacers) and let the glue dry for about 20 minutes
before removing the weights for the next cycle.
Specimen Arrangement. The main considerations in arranging specimens on a sheet are assuring visibility
of important features of the plant and seeing to it that the plant does not exceed the margins of the sheet.
There is also an artistic element in the way a plant is arranged. One does not just randomly place a
specimen on a sheet, even if the above considerations are met. Bridson & Forman’s (1992) Herbarium
Handbook is recommended reading for good information and illustrations relating to mounting specimens.
Labeling: Typing, Attachment & Placement. Labels should be neatly typed or neatly written with permanent
ink (insurance of archival quality) and without errors. Family name should be in ALL CAPITAL letters. Genus
and species should be underlined.
Examples of correctly written scientific names are:
Sphagnum wulfianum Girg.
(note that there is NO underline between genus and species)
Sphagnum recurvum var.brevifolium (Lindberg ex Braithwaite) Warnstorf
(note “var.” and authors names are NOT underlined)
(note “sp.” refers to an undetermined species in the singular sense. “spp.” is plural and would never be used
on a normal herbarium specimen, because generally only one taxon is included per sheet or envelope. “sp.”
and “spp.” are never underlined)
Examples of incorrectly written scientific names inlcude:
Sphagnum wulfianum Girg.
(do NOT underline space between genus and species. Do NOT underline the author’s name(s))
Sphagnum recurvum var. brevifolium (Lindberg ex Braithwaite) Warnstorf
(Do NOT underline “var.” or “forma”)
Sphagnum sp. (Always underline genus and species)
(Although Deam adamantly supported capitalization of proper specific epithets, it is not accepted by
international codes of nomenclature).
The “Notes:” on the specimen label was deliberately designed as a very general category, because the kind
of data taken varies with investigator. Having a separate category for elevation, township and range, city,
county, country, etc., would end up wasting space and appearing sloppy, because in many cases one or
more of these data were not collected. The proper way of filling-out the notes section is to start with the most
detailed aspect of the location and work up to the most general aspect of the location. Other details such as
elevation and associated species can be included afterward. Example:
South facing slope of the riparian zone of the Elkhart River, T35N., R6E., Sec. 2, Elkhart County, Indiana, U.S.
A. Elevation: 804 ft. Growing among Impatiens capensis.
Make sure to include county wherever possible (most state floras use the county as the smallest unit of
distribution and range), and always include State and Country. While U.S.A. may be obvious to an American,
a foreigner may have no idea what country Indiana is in.
The collector’s name should be written out in entirety.
The date should include up to the first four letters of the month, followed by the date and year. Examples:
June 12, 1970
Aug. 15, 1984
Do not use numbers to represent months. It is too confusing because American and European sequences
and notations are different (e.g. 1.2.97 means February 1, 1997, in Europe, and 1-2-97 means January 2,
1997, in America, etc., etc.).
The determiner’s name should be written out if it is different from the collector’s name. If the collector
determined the specimen, then only the initials of the collector are needed in the “Det:” category.
Labels are attached with spray adhesive to the lower right corner of the herbarium sheet. Spray the label
and then affix it to the sheet (not visa versa). There should be no more or no less than 3 mm of space
between the edges of the label and the edge of the sheet. Labels should be straightly aligned, not crooked.
Ordering Supplies. The Swinehart Herbarium orders most of its supplies from the Herbarium Supply
Company, 3483 Edison Way, Menlo Park, California 94025, U.S.A. A catalogue of supplies may be obtained
by written request.
Placement of Accession Numbers. An accession label is placed either on the specimen envelope (in the
case of bryophytes, etc.) or on the lower left corner of the herbarium sheet. The accession number of the
specimen is stamped in the box next to the acronym using a number stamp. Re-inking of the stamper should
occur the night before the next accession, because the ink is viscous and takes time to absorb into the pad.
In addition to placing an accession number on the sheet or envelope, there is also a space to stamp on the
label itself. This is done in case the label ever becomes separated from the sheet. Having accession
numbers on both will help in re-matching the label to the sheet/specimen.
Record Keeping. Magnetic storage alone is not an acceptable means of record keeping. There MUST be
some form of a “hard” copy to protect records from being erased and lost. Reliance on computers has
resulted in sloppy record keeping. Accession numbers and specimen data are to be recorded in these
volumes whenever new specimens are processed and added to the Herbarium. Make sure to include the
date the specimen was accessioned when adding information to the record book. Record data neatly and
cleanly. Follow the format of previous entries.
Click on thumbnail for larger image
Computer Database. Data recorded in the herbarium log are also entered into a computer database. The
Swinehart Herbarium uses FileMaker Pro.
Deposition of Specimens in the Herbarium. Once a specimen has been assigned an accession number
and the appropriate record keeping has been conducted, the specimen is ready for decontamination and
placement into the Herbarium. In the Swinehart Herbarium, there is an “in-process” folder. New specimens
can be placed in this folder, and as several specimens begin to accumulate, they can be added to the
respective locations in the herbarium stacks. This saves time and limits handling of specimens by reducing
the number of trips to the stacks.
Credibility of Annotations. Determining the credibility of someone's ability to reliably annotate a specimen
is rather subjective. Generally, annotation of specimens from the Swinehart Herbarium should be conducted
by professionals with demonstrated skill in taxonomic botany. This may include graduate students,
professors, non-academic scientists, and exceptional undergraduate students and plant enthusiasts. The
decision to grant authority to annotate specimens is at the discretion of the curator.
Annotation Labels. An annotation label should be relatively inconspicuous and should not detract from the
appearance of the sheet/specimen. In general, annotation labels should be limited in size to no larger than 5
x 10 cm. They may be placed above or beside the original specimen label or where space will allow if the
former locations are not feasible. Annotation labels should include the name of the annotator, associated
institution or project, date, and the full scientific name for which the specimen should be referred along with
other pertinent notes.
Placement of Annotated Specimens in the Herbarium. Assuming credible annotations, any specimen
which is referred to a truly different taxon than previously labeled should be moved to the correct folder.
Voucher Specimens and Exchanges
The Swinehart Herbarium is an active collection. Properly identified voucher specimens (mounted or
unmounted) associated with research projects and floral inventories are welcome. A small collection of plants
for exchange programs with other herbaria is maintained. Trading or exchanging specimens with other
herbaria is the most efficient way of increasing collections without travelling. Records of exchanges with other
herbaria are kept. A standard loan form is used to document exchanges. Additionally, an exchange
summary is kept for each herbarium for which exchange has occurred.
The written correspondence of an herbarium is an extremely important and interesting aspect of herbarium
operations. It represents an historical record of not only the herbarium and its scientists, but of plant
taxonomy and scientific culture as well. Copies of all letters (including e-mail) sent out by the Swinehart
Herbarium (especially those directly dealing with the Swinehart Herbarium and its daily procedures and
exchanges) are placed in three-ring binders. Binders are stored in the curator’s office.