Appendices & Glossary - Botanical Research Institute of Texas

APPENDIX EIGHT
WHAT IS AN HERBARIUM?
COLLECTING HERBARIUM SPECIMENS 1
A collection of pressed and dried plant specimens is known by botanists as an herbarium (plural herbaria).
The word herbarium, as originally used, referred to a book about medicinal plants. Pitton de
Tournefort (early French botanist and physician) around 1700 used the term for a collection of dried
plants, and his usage was taken up by Linnaeus (Arber 1938; Stearn 1957; Birdson & Forman 1992).
Largely through Linnaeus’ influence, the word herbarium thus replaced such earlier terms as hortus
siccus (dry garden) or hortus hyemalis (winter garden) (Arber 1938; Stearn 1957; Shinners 1958). Luca
Ghini (1490?–1556), a botany professor at the University of Bologna, Italy, is considered to have been
the first person to dry plants under pressure, mount them on paper, and thus preserve them as a permanent
record (Arber 1938; Birdson & Forman 1992). The usefulness of such specimens was soon apparent,
and his technique was disseminated over Europe by his pupils (Arber 1938). By the time of Carl
Linnaeus (1707–1778), this method was well known and widely used (Stearn 1957). The oldest surviving
herbarium is that of Ghini’s pupil Gherardo Cibo, who began to collect plants at least as early as
1532 (Arber 1938). Other early herbaria were developed in various countries, including England,
France, Germany, and Switzerland and, in all, more than twenty 16th century collections survive in
different European cities (Arber 1938; Valdés 1993). According to Stearn (1957), “The older herbaria
consisted of specimens on sheets bound into [book-like] volumes. Linnaeus never adopted this inelastic
and expensive procedure but mounted his specimens on loose sheets stored horizontally which
could be easily re-arranged and to which other specimens could be added when necessary. Probably
due to Linnaeus’ example and teaching this method became general during the second half of the 18th
century.” Modern herbaria still utilize Linnaeus’ basic system of mounting specimens individually on
loose sheets. Today about 16,000 specimens that were at one time in Linnaeus’ personal herbarium survive
in England, Sweden, and France and can still be studied (Stearn 1957). From these beginnings,
Holmgren et al. (1990) reported 2,639 herbaria worldwide with an estimated 272,800,926 specimens.
WHAT ARE HERBARIA USED FOR?
Herbaria are among the most important tools in studying the plants of a given area, with the reasons
for this importance being quite diverse (Benson 1979; Birdson & Forman 1992; Valdés 1993). Specific
ways in which herbaria are used include: 1) Herbaria are invaluable reference collections used as means
of identifying specimens of unknown plants. Even experienced botanists frequently need to refer to
herbarium specimens in order to definitively identify a plant in question. In this way botanists are able
to identify material for such organizations or individuals as poison centers, medical researchers,
ranchers, law enforcement agencies, agricultural extension agents, or gardeners. 2) Herbarium specimens,
which have an indefinite life if properly protected (the oldest in existence go back almost 500
years), also provide a valuable historical record of where plants occurred in the past in both space and
time. A local example can be seen in Julien Reverchon’s collections from the late 1800s and early 1900s
made in the Dallas area. Because the natural vegetation of Dallas has been almost completely destroyed,
without Reverchon’s specimens we would have almost no knowledge of the previous richness
of that flora. Also, herbarium specimens provide early documentation of the introduction of foreign
weeds or the previous geographic limits of native plants (Shinners 1965). These examples demonstrate
the importance of herbaria as a special type of museum, and as such they are important storehouses of
irreplaceable data. In a real sense, herbaria serve as “… a source of primary information about man’s explorations
and observations of the earth’s vegetation. ….” (Radford et al. 1974) and as “… the raw data
underpinning our scientific knowledge of what kinds of plants exist, what their diagnostic features
1 Reprinted from Diggs et al. (1999).