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Herbarium collections
 Dried plant specimens are stored as a reference for plant identification in collections known as herbaria. Well labelled and kept in controlled conditions of low humidity they can be used for centuries, while living plants are much more susceptible and their survival as a point of reference cannot be guaranteed. When plants are named the names are nearly always linked to stored herbarium specimens, the ‘types’ for that name, which are given special protection. Databases of collections are currently being developed, and images of many collections, especially the types, are becoming available. More...
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Herbaria
Databases of details and images of type collections in herbaria
Bamboo specimen images
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More...
Herbaria are found in botanical institutions throughout the world. Herbarium collections are most useful as a specialist resource for those who revise and describe plants and their names, for several reasons. Nevertheless, they are very important, not least because this is where the ultimate reference material for bamboo names is located, as all names are fixed to a herbarium specimen, the ‘type’ of the name, critical for good nomenclature.
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- Herbarium material is pressed flat and completely desiccated, which makes it rather different in appearance from fresh material
- Unless a specimen is the actual type specimen for that species, there may be several different names attached to it
- Different herbaria arrange their plants following different classification systems, often out of date for bamboos, making species hard to find
- Knowledge of which parts of bamboos are important for identification use to be poor, and older herbarium collections may lack more important parts, such as culm sheaths
- Different herbaria specialize in different plant groups and plants from different areas, and those that have comprehensive bamboo collections are few and far between
- As long-term sterile preservation of the specimens is of paramount importance, fresh material is not allowed in the herbarium for direct comparison, because it could harbour pests
- Herbarium material is fragile, and staff are cautious about allowing too much handling, as it has to be stored indefinitely
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Increasingly, however, herbarium collections are being digitized, catalogued, and made available on-line, especially for type specimens. This makes
the material much more accessible, and as it does not need to be physically handled, it is thus more appropriate for wider use. However, the reservations concerning identification by picture also apply to such digitized images, which are usually after all just fairly low resolution scans of part of a long-dead plant. Many of the finer details of bamboo plants require a much closer inspection, usually using a microscope. Higher resolution scans are becoming available, their use being somewhat restricted by the large file sizes involved, but they still do not have the resolution of a good macro or microscope. Herbarium specimens were not collected, mounted, or scanned in order to provide the best images of critical parts for identification. If photos are required then it is better to photograph the living plant properly in the first place. Herbarium collections were made for close personal inspection, and images are a screening tool to see which ones should be requested on loan for a closer inspection. Further examples of herbarium specimens can be found by searching the on-line databases of several herbaria, but not all have yet started to database or to include bamboos.
Older herbarium specimens are often very problematic, and they can be very hard to identify. Many might be discarded if sent in to a
herbarium today, but they are often of historic importance or they may be the definitive reference ‘type’ for names. In the bamboos the absence of culm sheaths, and often leaves as well, is a common situation arising from the belief that flowers would provide better indication of a plant’s affinities. Unfortunately this is not the case, and newer collections have often been made, without any flowers at all. This makes it difficult to relate the older and newer collections, which leads to problems when different names are tied to older, flowering and newer, vegetative collections. A further problem with herbarium material is that hairs and appendages have long since departed. Only by closely inspecting with a microscope is it possible to see remnants and traces indicating where they were once attached. Colours als fade with time, especially if the collections have been exposed to strong light.
Newer herbarium collections are usually more comprehensive and in better condition, and many new collections are constantly being made and distributed. Collectors today are often photographing plants in the field as they make collections to get the best images of fresh material possible. Linking of such images to the images of the collections will also be possible in the future, and the inclusion of close up photos of the more critical parts of collections will also be undertaken. Currently huge amounts of memory are used up recording the blank mounting sheets, while important parts of the plant are not recorded in sufficient detail.
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