herbarium

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Vitellaria paradoxa , herbarium evidence from the Herbarium Senckenbergianum
Drying oven for herbarium specimens from a gas stove and a wooden frame, herbarium of the University of Ouagadougou .

A herbarium or herbarium (from Latin : herba = herb) is a collection of preserved (mostly dried and pressed) plants or parts of plants for scientific purposes or for those interested in botany . Scientific herbaria sometimes also have partial collections of wet-preserved material (in alcohol) or wood collections (xylarium).

Individual plants or their parts are glued to a herbarium sheet as a recognizable unit (herbarium document). They should come from a collection event and the circumstances of the find should be documented (date, location, location, collector, etc.).

Purpose of a herbarium

A herbarium allows the botanist to compare plants of different origins and to check uncertain determinations ("comparative herbarium ") or to prove the occurrence of certain species at their growing locations ("documented herbarium"). By evaluating older herbaria, changes in the frequency or shifts in the distribution areas can often be traced. The later (re-) identification of a plant in the herbarium is almost always possible; namely, the spatial structures are retained during drying and pressing. Colors can fade or change; however, one uses certain "rules of thumb" - so one knows that yellow parts of plants slowly turn black after drying.

In most cases, identification keys and floras are also based on the comparison of herbarium specimens; only rarely and in exceptional cases can the species, which are often rare and which grow in widely spaced, inaccessible regions, be compared directly in the field. This makes it paradoxically easier in some cases to identify herbarium specimens of rare species up to the species than living specimens directly on site. In addition to shape and color, dimensions such as the length and width of plant organs in preserved plants very often differ from those of fresh specimens. This must be taken into account when making a comparison.

The creation of a herbarium was previously a prerequisite for the pre-examination as a pharmacist . Even today, many universities in biology and related courses require the creation of a small herbarium as an exercise. In some cases, a small herbarium is set up as part of biology classes at school; the requirements here are of course much lower.

Herbaria as collections

A scientific herbarium is a special case of a research collection (or scientific collection) with the usual tasks and problems of such an institution. It is usually managed by a curator who, depending on the size of the collection, is supported by collection assistants and technical staff. Smaller herbaria, with fewer than about 50,000 herbarium specimens, often face considerable problems in this regard. Often no special, full-time curator is designated; it is expected that another employee of the museum, the university or another institution that maintains the herbarium will take care of this task alongside his other duties. For the curation of even a smaller collection, roughly estimated, a time requirement of an absolute minimum of a quarter full-time position is estimated. In addition to the tasks of verifying and comparing, a whole range of other tasks must be taken into account. Students and faculties are to be provided with material for practice and training purposes. Scientists from other departments, for example vegetation experts and biogeographers, but also archaeologists (archaeobotanists) and many others should be supported in their work as a service. Inquiries from other institutions for collection material must be dealt with and, if necessary, its dispatch organized. Ideally, issues of botany and biodiversity in general should be publicly informed and advertised, amateur and hobby researchers should be supported and the public should be informed by providing data.

A particular problem, with increasing importance, is data management. As in other collections, the data used to be stored in catalogs and on index cards. When it comes to data storage in IT systems, as in all comparable cases, standardized registry and exchange formats must be developed and ensured. Constant maintenance of the database is necessary, for example if the valid scientific name of a species changes or if a specimen specific to the species is assigned to a different species by another botanist. Platforms for data exchange such as GBIF ( Global Biodiversity Information Facility ), Darwin Core (standard of the Taxonomic Databases Working Group (TDWG)) or BioCase (Biological Collection Access Service) and others are not always fully compatible with each other.

Herbarium evidence

A herbarium document is usually a dried and flattened specimen of a plant or, in the case of larger plants, a collection of parts of it, such as leafy shoots or twigs, inflorescences and flowers, etc., which is glued to a cardboard or sheet of paper. Essential information is documented on an affixed label, without which evidence is of little scientific value. In the case of plant species that are difficult to store in this form due to their morphology, for example because they are too large and bulky or that lose their shape when drying, other conservation methods are used instead. There are also standardized methods of their own for herbarium specimens of mosses , lichens and fungi , which differ from the procedure for vascular plants.

Smaller private herbaria often do not meet the quality requirements of scientific herbaria, but often do not even strive to achieve them.
Herbarium book with Japanese plants, Siebold Collection Leiden, 1825?

The plant collected for a herbarium sheet should be complete and of good quality. In the case of large plants, the plant parts relevant for the determination (flowers / fruits, leaves, shoots, roots) should be present. The plant material should be pressed and dried without damage (mechanical, fungal attack, yellowing) and interesting components should be clearly visible. In order to create a herbarium record, plants must first be collected. For this purpose, specimens that are as typical as possible and representative of the population should be selected. As a rule, only blooming or fruiting specimens are selected. Usually several specimens should always be herbarized. If parts of different individuals are mounted on an arch to complete it, however, there is a risk that they represent different plant families. The collector must have a botanical knowledge so that he knows which characteristics are essential for the relevant group and selects the material accordingly; thus certain species can only be determined in the flowering or in the fruiting state. In the past, botanizing drums were used for collecting , today plastic bags serve this purpose. Certain plants, for example from the Papaveraceae family , have to be pressed in the field, otherwise the clusters will disintegrate (here: lose the petals).

There are several methods for further treatment of the collected plants, which have their advantages and disadvantages depending on external circumstances (climatic conditions, space requirements when traveling, etc.). If possible, the plants are usually dried and pressed immediately afterwards. To press the plants, either special lattice plant presses with tension springs are used or, in the simplest case, the plant is placed between blotting paper (alternatively newsprint) and wooden boards and weighed down. The paper used for drying should be changed regularly, otherwise the plants run the risk of going moldy, but the sheet of blotting paper with the herbarium document itself should never be changed until it is completely dry. Spacers are often added to allow air to circulate. It is important to clearly mark the receipts at this stage in order to prevent later confusion. While simple drying between absorbent paper can be sufficient under optimal conditions, it is usually necessary to artificially dry the receipts over a heat source.

In tropical climates in particular, the herbarium specimens are alternatively stored initially using alcohol in order to later be dried under better conditions. This procedure is known as the Schweissfurth method. For this purpose, the documents pressed between blotting paper are placed in tightly closing plastic bags in alcohol in the absence of air.

The completely dried plants are then mounted on a herbarium arch for permanent storage. To prevent damage when handling, the plants are glued to the herbarium sheet with rubberized paper strips. The flat gluing, or even the welding of the arches under plastic film, which is sometimes used in lay herables, are not acceptable in scientific collections. The minimum information on a herbarium sheet is the place of discovery (if possible, GPS coordinates), date of discovery and finder. Usually the scientific name of the plant is also given. It is customary for the collector to assign a unique collection number for each herbarium. Information on location, frequency, accompanying plants and other observations are also important for future observers. In addition, characteristics should be noted that can only be determined in living plants (total height of trees, color of fresh flowers, etc.).

In order to ensure permanent access to the collected plants, the herbaric plants are stored under climate-controlled conditions. Dry storage is important to prevent rot and mold . Dust lice , museum beetles, or other collection pests that live on dried plants are best controlled by occasional freezing . The individual herbarium sheets are ideally stored horizontally in flat compartments. Views on the use of plastic film for covering instead of paper are divided. The name of a plant species often goes back to a specific dried specimen, the holotype of that species, in a scientific herbarium.

Plant species can be subject to species protection according to national law or international treaties and agreements . In Germany, for example, this applies to species that are “specially” or “strictly” protected under the Federal Species Protection Ordinance (BArtSchV). For this reason, precise information about the plant species present must be obtained before herbarization. If necessary, an exemption must be applied for from the competent authority.

Herbarium evidence for DNA extraction

In addition to their traditional significance, herbarium specimens today, like other specimens in scientific collections, are increasingly important for obtaining DNA specimens, the sequence of which is an important basis for taxonomy and systematics ( phylogenomics ); In addition, certain and named documents serve as a reference for species identification using DNA barcoding . Due to the further development of the corresponding techniques (called “next-generation sequencing”) it is now possible to use older documents with DNA that has been degraded due to age-related decay; Even the specimens treated with alcohol using the Schweissfurth method, which were previously hardly usable, now provide usable material. However, the methodological use of old herbarium specimens is extremely difficult because the samples are often contaminated with foreign DNA through contamination, which can falsify the results. The more complex methods developed for aDNA must be used here.

Virtual herbarium

Main article: Virtual herbarium

In the meantime, some herbaria have digitized parts of their collections in order to be able to make them available to a broad public, for example via the Internet. Herbar Digital was a research project to rationalize the virtualization (digitization) of botanical evidence. Mass digitization routes were used in the 2010s.

Emergence

In the early modern period, the term “herbarium” initially referred to a book of herbs . On the other hand, collections of dried plants were called "Herbarium vivum", "Herbarium siccum" or "Hortus hiemalis" (Latin for "winter garden") because it was supposed to replace the view of living plants in the garden in winter. The first mentions of pressed plants come from the 15th century. The earliest herbaria were laid out in the first half of the 16th century with the establishment of botanical gardens in central Italy. The earliest preserved herbarium, now in Florence, is that of the Italian botanist and priest Michele Merini , which was laid out around 1545. The invention is attributed to Merini, but more often to his teacher Luca Ghini (1490–1556), who founded the world's first botanical garden with the Orto botanico in Pisa. The early herbaria were mostly bound together in a book (codex), analogous to herbal books. Andrea Cesalpino , for example, gave such a “liber ex plantis agglutinatis” to Duke Cosimo I de 'Medici . The herbarium of Leonhard Rauwolf , in which he collected 513 sheets of plants from his journey to the Orient, is preserved today in Leiden . Probably the oldest preserved German herbarium is that of Caspar Ratzenberger from 1592, it is exhibited today in the Ottoneum Natural History Museum in Kassel. While these early herbaria were initially more or less something like collected cabinets of curiosities, following the work of John Ray, Joseph Pitton de Tournefort, Carl von Linné, Augustin Pyrame de Candolle and other researchers of their time, the establishment of systematic herbaria began. The herbarium of the Swiss botanist Caspar Bauhin is one of the first in which all known plant species were to be collected according to the systematic established by Linnaeus. He now also used his herbarium (now in Basel) as a means of research, in which he compared the collected plants with one another and, on this basis, made differential diagnoses. The herbarium of the Irish botanist Hans Sloane (1660–1753) was bought by the British government after his death, it forms the basis of the herbarium of the Natural History Museum . Carl von Linné set up his work, which is fundamental for plant taxonomy, primarily on the basis of the herbaria of other contemporary botanists, over that of the Dutch lawyer George Clifford III. he wrote his work Hortus Cliffortianus . Linné's own herbarium, which contains “only” 14,000 specimens, was sold to England by his widow after his death. It is now with the Linnean Society of London . Many of the documents held there are available in digital form.

Great herbaria

Scientific herbaria are usually attached to botanical gardens , natural history and natural history museums or biological university institutes, mostly specializing in botany. All large and important international herbaria are listed in the “Index Herbariorum” directory. This first appeared in 1935, at that time still in print. As of December 1, 2016, the Herbariorum index shows 2962 active scientific herbaria in 176 countries worldwide. These hold 381308064 herbarium specimens. A total of 11548 scientific staff are employed at the herbaria. Most of the herbaria can be found, with 792, in North America and, with 695, in Europe, 69 of them in Germany, 19 in Austria, 16 in Switzerland. In contrast, there are only 47 herbaria in the whole of Africa.

The ten largest herbaria in the world (according to the Herbariorum Index) are, in descending order:

Other large herbaria in the German-speaking countries are for example

literature

  • Sven Linnartz: The botanical excursion - step by step to your own herbarium . Quelle & Meyer-Verlag, Wiebelsheim 2007 (2nd edition), ISBN 978-3-494-01433-3 .
  • Christof Nikolaus Schröder: Catalog of the abbreviations used on herbarium specimens - Catalogus Abbreviationum in Schedis Herbariorum usitatorum. In: Kochia 12 (2019): 37-67, ISSN 1863-155X. on-line

See also

Web links

Commons : Herbaria  - collection of images, videos and audio files
Wiktionary: Herbarium  - explanations of meanings, word origins, synonyms, translations

Individual evidence

  1. ↑ John Parnell, Tim Rich, Andrew McVeigh, Astrid Lim, Sean Quigley, David Morris, Zeno Wong (2014): The effect of preservation methods on plant morphology. Taxon 62 (6): 1259-1265. doi: 10.12705 / 626.3
  2. ↑ http://www.uni-bamberg.de/fileadmin/020722/Downloads/Anlegen_eines_Herbariums_und_eines_Transekts.pdf
  3. ^ Neil Snow (2005): Successfully Curating Smaller Herbaria and Natural History Collections in Academic Settings. BioScience 55 (9): 771-779. doi : 10.1641 / 0006-3568 (2005) 055 [0771: SCSHAN] 2.0.CO; 2
  4. ↑ Vicki S. Funk (2003): 100 Uses for an Herbarium (well at least 72). American Society of Plant Taxonomists Newsletter 17 (2): 17-19.
  5. ^ According to AG Miller & JA Nyberg (update: AP Davis): Collecting herbarium vouchers. Chapter 27 in L. Guarino, V. Ramanatha Rao, E. Goldberg (editors). Collecting Plant Genetic Diversity: Technical Guidelines - 2011 Update. Bioversity International, Rome, Italy. ISBN 978-92-9043-922-6 . online and download at Crop Genebank Knowledge Base
  6. ^ Sven Buerki & William J. Baker (2015): Collections-based research in the genomic era. Biological Journal of the Linnean Society 117 (1): 5-10. doi: 10.1111 / bij.12721
  7. ↑ Leon Perrie & Lara Shepherd (2014): Extracting DNA from herbarium specimens. Australasian Systematic Botany Society Newsletter 160: 8-9.
  8. ↑ Naturalis Biodiversity Center: Digitizing the herbarium
  9. ^ Karl Mägdefrau: History of Botany. Life and achievements of great researchers. Springer-Verlag Berlin and Heidelberg, 2013. ISBN 978-3-642-39400-3 , on page 36.
  10. ↑ Christina Becela-Deller: Ruta graveolens L. A medicinal plant in terms of art and cultural history. (Mathematical and natural scientific dissertation Würzburg 1994) Königshausen & Neumann, Würzburg 1998 (= Würzburg medical-historical research. Volume 65). ISBN 3-8260-1667-X , p. 150 ( nature observation on the herbarium copy ).
  11. ↑ Dietrich von Engelhardt (2011): Luca Ghini (1490–1556). Il padre fondatore della botanica moderna nel contesto dei rapporti scientifici europei del sedicesimo secolo. Annali del Museo Civico di Rovereto, Sezione di Archeologia, Storia e Scienze naturali 27: 227-246.
  12. ^ Herbert Hurka, Barbara Neuffer (2011): History and meaning of herbaria. Osnabrücker Naturwissenschaftliche Mitteilungen 37: 115–134.
  13. ^ The Linnean Society of London: Linnaean Herbarium
  14. ^ Index Herbariorum: A global directory of public herbaria and associated staff. New York Botanical Garden's Virtual Herbarium. edited by Barbara M. Thiers
  15. ^ Website of the Royal Botanic Gardens, Herbarium
  16. ^ The National Herbarium of the Netherlands (NHN), Department of Botany of Naturalis Biodiversity Center, Leiden
  17. ↑ Harvard Herbaria and Libraries
  18. ^ Herbarium Berolinense, Botanical Garden and Botanical Museum Berlin
  19. ↑ Herbarium Haussknecht, Jena
  20. ^ Herbarium of the Botanical State Collection Munich
  21. ^ Herbarium Hamburgense (HBG), Hamburg
  22. ↑ Herbarium Senckenbergianum, Frankfurt