Herbarium specimens

Several samples of the less common genera in this extensive family were supplied in the form of gleanings from herbarium specimens. 

Only three genera and four species had been reported to give positive alkaloid tests until the appearance of a scries of papers on the chemistry of Quararibea funebris (Zennie and Cassaday, 1990) and a brief survey of the folk-medical uses of several genera (Raf-fauf and Simon, 1988). The results of this last study, which included extensive testing of herbarium specimens, are repeated here for a more complete survey of the family. A total of 349 samples representing 135 species were tested. 

The family is known to be alkaloidal (Brossi, 1985). Most of the tests performed in this survey were done on bits of material selected from herbarium specimens. 

Little of the chemistry of the Lythraceae was known prior to the 1960s beyond reports of the qualitative presence of alkaloids in a few genera. With the recognition of the novel alkaloid structures in Decodnn and Heimia, an examination of material from other genera gleaned from herbarium specimens was undertaken. The published results are included in those reported here. 

Considering the size of the family, its chemistry is not that well known. Alkaloids were detected in some genera as early as 1892, and records now exist for (heir presence in some 800 species of 180 genera. To this record, several of the following species may now be added. With few exceptions, they were tested as herbarium specimens in the Oakes Ames Herbarium of Harvard University in deference to the size of the family, samples were taken from every tenth sheet regardless of genus or species. 

Of the total of 1,243 species of orchids examined, most were found to be alkaloid-negative. However, it is fair to note that many of these had been listed by others as positive, suggesting a set of false negative results due to any one factor or a combination of the factors discussed in the Preface with respect to herbarium specimens and their preservation. 

Several genera of the family have been assigned to a separate family, Naucleaceae, by some taxonomists. The family is considered here in its extended and generally accepted sense. Many of the tests on the relatively uncommon species were conducted on small samples gleaned from herbarium specimens. 

Parr, J. F., Dolic, V., Lancaster, G, and Boyd, W. E. (2001). A microwave digestion method for the extraction of phytoliths from herbarium specimens. Rev. Palaeobot. Palynol. 116, 203-212. 

Following this earlier work, nearly 150 hyperaccumulators of Ni have now been reported (Table 4-3), largely as the result of chemical tests on herbarium specimens. This has led to increased interest in these plants for the reasons outlined in the introduction of this chapter. 

A number of studies have indicated that DNA can be successfully extracted from herbarium specimens (personal observation).13-15 It is very unlikely that isozymes will ever be routinely extracted in an active state... 

United States, permits are often mandatory for plant collections made within city, county, state, and national parks, as well as for those made in wilderness areas, conservancies, and other protected sites. Such permits are usually specific as to species and quantity of material allowed for collection and expire within 6 to 12 months. Many require submitting a detailed proposal, depositing a set of herbarium specimens, and presenting periodic field or progress reports (personal observation).23... 

Ayacucho is often necessary to finalize the paperwork. A duplicate set of herbarium specimens (usually including the unicates) must be deposited in a national or local herbarium often, a preliminary field trip report and/or a complete copy of field notes must be submitted after the expedition before the investigator is permitted to leave the country. 

An essential, and sometimes overlooked, part of plant tissue collection is the herbarium voucher. Herbarium specimen vouchers are usually obtained with field-collected material, but they are often neglected when the tissue is obtained via seeds or through an intermediate source (botanical garden, colleague, etc.). Botanical garden collections are numbered by accession, and the original voucher information (collector and number) can usually be traced in records maintained by the botanical garden. This information should be obtained and recorded, but it is also prudent to have a second voucher made at the same time as the tissue is collected. Label... 

Quite at the beginning of this chapter I mentioned "different kinds of plant taxonomists engaged in different kinds of research". I hope that indeed it became clear that under the roof of plant systematise there is a large diversity of activities and purposes. One may find a plant taxonomist at work behind a chemical apparatus, between piles of herbarium specimens, in a garden between flowers encased in gauze, in a cold culture room between bottles with seaweeds, in a tropical forest, as well as behind a scanning electron microscope or a computer. 

A good herbarium specimen must give the investigator the best possible information on the plant concerned. In other words, the collection should preferably contain all parts of the plant and should be well annotated so as to provide all information not visible on the herbarium specimen. 

Make it a habit not to rely on your memory but to write your notes at the collecting site ar-1 not to wait till the end of the day, or worse still, to put it off to the next day. After collecting your specimen give it a number tag and enter notes in your collection book under the corresponding number. It is important to take down all particulars that disappear or are invisible in the herbarium specimen (see also van Steenis 1977). Notes should include ... 

After making a sample of a plant the procedures for preservation followed depend on various factors such as time, money, assistance available, etc. Them are two methods of preparing a herbarium specimen> directly drying in the field or provisionally preserving the material on alcohol and drying them later in the herbarium (wet method). 

At the start of a revision usually a large amount of herbarium specimens is present. Select all material that is needed for your special purpose, e.g. for a local or regional revision, or all material for a monographic treatment. 

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