A Flowering for the Ages

Botanists who classify and name plants are called plant taxono­mists, plant systema­tists, or systematic botanists, most of whom work in her­baria, a name first applied by Carolus Linnaeus (1707-1778), the great Swedish systematist. A herbarium, the plant taxono­mist’s basic reference source, is a collection of preserved plant specimens, mostly pressed and dried (although certain specimens must be preserved in liquid, and some specimens are dried but not pressed be­cause they are too bulky), and mounted on high quality pa­per. These mounted papers are arranged in systematic order, either in the sequence of an accepted classification system, or alphabetically, or both, and which are available for refer­ence or study. The term “her­barium” can be applied not only to a collection of pressed and dried (and otherwise preserved) plants, but also to the institution which is estab­lished around such a collec­tion. At one time, however, the term “herbarium” referred not to a collection of plants but, instead, to a book about me­dicinal plants. Herbaria are associated with many general museums, most natural his­tory museums, numerous colleges and universities, bo­tanical gardens, and certain government agencies.

Plant taxonomy originated in the need for precise communication, mainly due at first to the medicinal uses of plants. Among the earliest botanical institutions were the “simples” (medicinal or drug plants) gardens once part of ancient and medieval monasteries. The modern academic botani­cal institution is a product of the Italian Renaissance, during which some of the “simples” gardens, used in training phy­sicians, became affiliated with universities. Perhaps the old­est of these academic gardens is at the University of Padua in Padua, Italy, where in 1533, Francis Bonafede, a professor of medicine, secured a “profes­sorship of simples,” the first professorship of botany in Europe. Bonafede was able to establish and develop a garden of “simples,” financed by the Venetian Senate, which later, on June 29, 1545, officially established the botanic gar­den. Today, the garden com­prises an area of about five acres, consisting of plantings, a large herbarium and a library of more than eighteen thou­sand volumes.

Almost as old is the botanic garden at Pisa, Italy, estab­lished in 1543, with Luca Ghini (1490?-1556) as its first director. In 1545, Ghini was assigned the task of establish­ing a botanic garden at Flor­ence, probably the third oldest of the gardens. Gardens had existed in ancient Rome, but the first botanic garden for instruction, similar to the Padua, Pisa and Florence gar­dens, was the Vatican garden, established around 1556 by Michele Mercati, a student of Ghini’s student, Andrea Ce­salpino, the second director of the garden at Pisa. These uni­versity gardens justified their existence by disseminating knowledge about plants to the public and are the direct ante­cedents of today’s botanic gardens and herbaria.

Botanists did not make any systematic attempts to pre­serve the specimens they stud­ied until early in the sixteenth century when there was a tremendous outburst of botan­ical activity, particularly in Italy. Prior to that time, a few dried herbs, intended primar­ily as a supply for medicinal purposes, served as compara­tive material. The beginning, around the year 1530, of the herbarium (although this term was not applied until about two hundred years later) as a collection of pressed and dried plant specimens mounted on paper for a permanent record has been attributed to Luca Ghini. Ghini generally is cred­ited with being the sole origi­nator of the art of herbarium-making, which was dispersed throughout Europe by his students. Gherards Cibo, one of Ghini’s students, began collecting and preserv­ing specimens as early as 1532. John Falconer, an Englishman, possessed a herbarium accord­ing to writings of Lusitanus in 1553 and William Turner in 1569. Falconer learned about herbarium-making either di­rectly from Ghini or, indirectly, through one of his students. Cesalpino, perhaps Ghini’s greatest student, as well as his master’s successor at Pisa, also created a herbarium; it con­sisted of seven hundred and sixty-eight well-mounted plants and is still in existence, being one of the oldest, if not the oldest, known plant collec­tions. It is only logical that the establishment of the university gardens and the preparation of herbaria would have occurred concurrently and undergone parallel development.

As the Renaissance blos­somed, gardens and accompa­nying herbaria were created throughout Europe. By the mid-eighteenth century, nearly every national capital and university boasted some sort of botanical facility. Plant spec­imens were arriving from everywhere, including North America, and the number of herbaria increased tremen­dously. Nations such as Great Britain, which claimed large colonial empires, exhibited the most rapid and impressive growth of herbaria and botanical gardens, in addition to the development of some of the great botanical institutions of the world with impressive facilities, including tremen­dous libraries and huge world­-collections of living plants in cultivation.

John Clayton (1685-1773), a native of England, was the first individual to seriously collect plants in what is now the United States, although a great number of plant specimens were already entering the gardens and herbaria of Eu­rope from the New World near the beginning of the seven­teenth century. Two contempo­raries of Gayton, who traveled and collected widely in eastern North America, were Mark Catesby (1680-1749), another Englishman, and Peter Kalm (1715-1779), one of Linnaeus’s students.

The first native North American botanists of note, and the first to earn a respect­able reputation among Euro­pean naturalists, were John Bartram (1701-1777), who es­tablished the first botanical garden in North America, and his son William (1739-1823). The Bartrams were farmers in present-day Philadelphia, but they were also scholars by predilection and avocation. John, who was a friend of Benjamin Franklin, Thomas Jefferson and other notable intellectuals, was a charter member of Philadelphia’s American Philosophical Soci­ety. Another notable father­-and-son team of botanists, who traveled and collected extensively in the United States and Canada during the late eighteenth and early nine­teenth centuries, were the Frenchmen Andre Michaux (1746-1802) and his son Francois-Andre (1770-1850).

In what is now the United States, several herbaria were in existence by the mid-eighteenth century. However, most of these, and even later ones, were taken to Europe where they were preserved. The first institutional herbarium estab­lished in the United States is commonly thought to be the herbarium of Salem College in Winston-Salem, North Caro­lina, created in 1772, the year the college was founded. There was, however, an impor­tant plant collection associated with the American Philosophi­cal Society in Philadelphia, which may have predated the Salem College herbarium. Benjamin Franklin founded the society in 1743, but the date of the plant collection’s establishment is not known. The collection, subsequently added to the herbarium of the Academy of Natural Sciences of Philadelphia, included many specimens collected during the Lewis and Clark expedition.

Together, the Salem College and American Philosophical Society collections constitute the earliest series of plant specimens that have been preserved in this country, and anticipate by one or more generations the collections at other facilities in the United States. Unfortunately, they were not the earliest speci­mens collected in the United States; those were taken to Europe where most of them are preserved in institutions such as the British Museum of Natural History, which in­cludes specimens collected by Pennsylvania’s John and Wil­liam Bartram, John Clayton’s Virginia collections (his own set was bequeathed to Gloucester County, Virginia, and would have been the earliest collection of plants preserved in this country, but the specimens were destroyed in a fire which consumed the county courthouse before 1800), and plants collected by Andre Michaux.

In North America, the Academy of Natural Sciences, Philadelphia, was unquestion­ably the most important botan­ical institution. Established in 1812, it is the oldest continuing major herbarium in the United States, and probably the oldest in North America. During the early years of the Republic, most plant specimens were sent to the Academy, and it was the facility European natu­ralists first visited upon their arrival in the United States. The American Philosophical Society’s collection acquired by the Academy, together with some of the Academy’s origi­nal material probably consti­tute the oldest plant specimens preserved in the United States, with the possi­ble exception of some, or all, of the Salem College collection. Several of the early naturalists who had close and important associations with the Academy were Benjamin Smith Barton, Henry Ernest Muhlenberg, Frederick Traugott Pursh, Thomas Nuttall, Lewis David von Schweinitz and Constantine Samuel Rafinesque. Many specimens collected by these intrepid naturalists remain in the Academy’s extensive col­lections.

Although several herbaria in the United States boast larger holdings than the Acad­emy of Natural Sciences, its collections consist of about one and a half million specimens. What is especially important about the Academy’s herbar­ium are the more than fifty thousand type specimens in the collections, an unusually high percentage, which rank its botanical collections as the most important in the Western Hemisphere. Certainly, no other herbarium in the Ameri­cas possesses so many type specimens documenting the nomenclature published by botanists in the eighteenth and early nineteenth centuries. The wealth of historically important specimens in the collections of the Philadelphia Academy is comparable to the major her­baria of Europe, but the Euro­pean herbaria do not possess the critical type material.

Herbaria range in size from small personal collections of perhaps a few hundred speci­mens to large collections of museums, botanical gardens, universities and colleges, pri­vate foundations and govern­ment agencies which have accumulated thousands to millions of specimens. In 1964, ten herbaria reported collections exceeding three million specimens; at least eight her­baria in the United States possess one million or more specimens. Although collec­tions are more accessible than ever before, it has been diffi­cult to assess herbarium re­sources because of the great number of private and small public herbaria which do not report their holdings.

The five most important botanical institutions in the United States today are the combined resources of the Gray Herbarium and the Arnold Arboretum of Harvard University in Cambridge, Massachusetts, consisting of more than three million speci­mens of vascular plants; the herbarium and garden of the New York Botanical Garden, which also contains more than three million specimens of vascular plants; the Botany Department of the U.S. Na­tional Museum of Natural History of the Smithsonian Institution, which is the Na­tional Herbarium, and which comprises about three million specimens of vascular plants; the herbarium and garden of the Missouri Botanical Garden in St. Louis, Missouri, which consists of more than two million specimens of vascular plants; and the herbarium of the Field Museum of Natural History in Chicago, Illinois, with more than two million specimens of vascular plants. Some university herbaria have impressive holdings as well; for instance, the herbaria at the University of Michigan and the University of California each claim a million speci­mens.

Until the time of Linnaeus, botanists pasted or sewed all mounted specimens in bound volumes of plain pages similar to books. The herbaria of the herbalists, and of most bota­nists as late as 1820, or even later, were preserved in this manner. The bound volumes were stored on shelves in an upright position, the same as books. Linnaeus abandoned this practice by mounting his specimens on single sheets and storing them horizontally, much like the method still used today. Although this method increased in popular­ity during the second half of the eighteenth century, it was not universally accepted; even as late as 1833, Asa Gray; the great American botanist, was offering bound volumes of grasses and sedges for sale.

In addition to changes in mounting, botanists began exchanging and depositing specimens in established col­lections. It is fortunate that such practices developed, for many herbaria have been destroyed by fire, insects, war, neglect and ignorance. All that remains of some collections are the duplicates sent to other institutions on exchange. A particularly regrettable exam­ple of the vulnerability of col­lections occurred on March 1, 1943, during World War II, when the great herbarium of the Berlin-Dahlem Botanischer Garten, containing four mil­lion specimens, and at that time the third largest herbar­ium and botanical garden in the world, was almost totally destroyed by bombing and the resulting fires during a devas­tating air raid. One unfortu­nate aspect of the early exchange material, however, was the scanty field notes kept by many of the early collec­tors, and the lack of concern for original labels as specimens were exchanged or sold.

More than three hundred thousand species of plants grow on earth, of which thirty­-five hundred species of vascu­lar plants grow wild in Pennsylvania. With sufficient knowledge and skill, a com­plete library of monographs, regional floras, identification manuals and a good herbarium, any unknown plant can eventually be identified. But, the identification of plants is difficult even for an expert.

Specimen plants stored in herbaria, such as the herbar­ium of The State Museum of Pennsylvania, Harrisburg, make accurate identification of unknown plants easy. The herbarium specimens, previ­ously identified by specialists, serve as comparative material for identification purposes. The specimens are studied and compared with the herbari­um’s library of monographs, regional floras and identifica­tion manuals.

The importance of the her­barium is not confined to its principal use as the preserver of comparative material for plant identification purposes; it is much more than a labora­tory for the plant systematist. The herbarium is of direct use not only to the plant taxono­mist but also to specialists in other areas of botanical re­search. The herbarium is im­portant to those studying plant distribution and geogra­phy, and to the paleobotanist studying fossil plants because of the need for comparison of fossil forms with living spe­cies. Botanists involved with economically important plants – such as food, orna­mental or medicinal plants, or plants yielding fibers, oils, latex or resins – frequently must refer to herbarium speci­mens. Plant ecologists often make use of the wealth of information about habitats which a herbarium contains. Herbarium specimens can be used by botanists studying plant anatomy and morphol­ogy and pollen structure. The herbarium can be a valuable teaching aid in the study of botany. It can be used to dem­onstrate features of plants which might not be available from other sources, such as the wild population or speci­mens in a botanical garden. This function of the herbarium enables researchers to become familiar with a wider range of plant forms and structures. Herbarium specimens also can be used to demonstrate spe­cific examples of the range of variation of a given species, genus or family, and to illus­trate the range of variation of a particular plant structure or organ. Or, herbarium speci­mens can be used simply to show the tremendous diversity of plant life on earth.

The founding legislation of 1905 and the Administrative Code of 1929 charged The State Museum of Pennsylvania with preserving examples of the flora of Pennsylvania. Acquisitions have been accom­plished through field collect­ing, donations, exchanges, transfers, loans and pur­chases. Specimens collected relate to the understanding and interpretation of the flora of Pennsylvania, and are truly representative of the plant life of the Commonwealth. The herbarium of The State Mu­seum of Pennsylvania is not the State Herbarium, however; that distinction belongs to the herbarium of the Pennsylvania Department of Agriculture. The plant collection of The State Museum of Pennsylvania is primarily a research and reference collection, serving the needs of staff, profession­als and interested museum visitors.

Although modest by com­parison with many herbaria, the herbarium of The State Museum of Pennsylvania continues to grow. While other states, particularly New Jersey, are represented, most of the specimens were collected in Pennsylvania. Field collecting has been limited to Pennsylva­nia but, occasionally, a dona­tion might be accepted which contains some non­Pennsylvania material. Every county, except Butler, is repre­sented in the herbarium. Some sections, particularly the southeast, are represented extremely well.

The inception of The State Museum’s herbarium dates to 1942, when two hundred and three specimens of vascular plants were transferred to the museum from the Pennsylva­nia Game Commission. The specimens had been collected by staff of the department of botany and plant pathology of the Pennsylvania State Univer­sity under the Federal Aid to Wildlife Restoration Act of 1937. This was the first of several donations of plant specimens received during the period between 1942 and 1980 from other agencies and insti­tutions. Large donations of vascular plant specimens were received from the herbaria of the Pennsylvania State Univer­sity in 1956, Bucknell University in 1970 and the University of Pennsylvania in 1970 and 1972. Between 1970 and 1974, twelve donations of vascular plant specimens were received from the Academy of Natural Sciences of Philadelphia, one of the nation’s most presti­gious natural history muse­ums. During that period, the Academy was reducing its holdings by eliminating some of its duplicate material. The State Museum expressed interest in obtaining the specimens about to be discarded, thereby paving the way for its most significant acquisition of vas­cular plant specimens: a selec­tion totaling more than four thousand specimens!

Although the specimens were drawn from the herbar­ium of the Academy of Natural Sciences of Philadelphia, some of the material received was originalJy contained in collec­tions acquired by the Acad­emy: The Philadelphia Botanical Club Collection; the herbaria of the Philadelphia Museum, the University of Pennsylvania and the Morris Arboretum; and numerous collections assembled by pri­vate collectors. Most of the specimens of the Academy’s donations were collected in southeastern Pennsylvania, but the northeastern part of the Commonwealth is fairly well represented. A considera­ble number of specimens were found in New Jersey. A great array of plant collectors and collections are involved, and naturally, a host of collecting localities. Nearly every year from the 1860s to the late 1950s is represented.

The most recent donation to the herbarium of The State Museum of Pennsylvania occurred in 1980, when two hundred and nine specimens of vascular plants were given by the Bowman’s Hill Wild­flower Preserve, located on the grounds of Washington Cross­ing Historic Park. The speci­mens were taken from the preserve’s herbarium, but many of them had been previ­ously acquired from other herbaria and, ultimately, from the collections of numerous individual collectors, a situa­tion similar to that of the Acad­emy of Natural Sciences of Philadelphia. The herbaria represented in the Bowman’s Hill material are The Academy of Natural Sciences of Phila­delphia, the University of Pennsylvania and its Morris Arboretum, and the Pennsyl­vania Department of Agricul­ture.

The herbarium of The State Museum of Pennsylvania has been the recipient of donations from dedicated individuals, as well as from institutions and agencies. During the period from 1962 through 1975, six hundred specimens were donated to the museum by plant collectors Robert C. Leberman, Dean H. Ross, Hans Wilkens, Timothy Plow­man and Paul E. Rothrock. Four donations by Ross, total­ing three hundred and thirty-seven specimens, constitute the State Museum’s most significant acquisitions of vascular plant specimens from an individual donor. Dona­tions have played – and will continue to play – an impor­tant role in the development of the herbarium of The State Museum of Pennsylvania.

Specimen acquisition for the herbarium of The State Museum of Pennsylvania has not been confined to dona­tions. Field collecting by mu­seum staff has been a source as well. From late in the 1940s through the early 1950s, Mar­ian Baker served as museum educator, and collected three hundred and three specimens of vascular plants. The mate­rial collected by Baker consti­tutes the first plant specimens ever collected by a member of museum’s staff, and was the only material added to the herbarium between 1942, the year of its initial acquisition, and 1956, when the next dona­tion occurred. Since then, numerous specimens have been added to the growing collections.

As any botanist will ex­plain, a herbarium is not merely a collection of pre­served plants – it is an educa­tional and research institution as well. It is a basic resource for the study of systematic botany and other disciplines of plant science, while serving as a reference and documentation center and a data storehouse. A herbarium can be a useful teaching aid or a fascinating hobby but, more importantly, it is a reference collection for the identification of plants and a body of information for bo­tanical research. A herbarium is the most essential tool for research in plant classification, phylogeny and plant geogra­phy because it serves as a permanent record of the distri­bution of each species, its range of variability, and the correlation of that variability with geography and habitat. The great diversity of plants within a given geographical area or political boundary, or even within a single circum­scribed habitat, is demon­strated clearly in a herbarium. A systematic botanist writing a regional or local flora, or a monograph, relies largely on herbarium specimens. Prop­erly maintained, the speci­mens in a herbarium may last for hundreds of years, and serve as a record of the flora of a particular place and time, and of the work of relentless collectors and researchers.

For Further Reading

Benson, Lyman. Plant Classifi­cation. Boston: D.C. Heath and Company, 1957.

Core, Earl L. Plant Taxonomy. Englewood Cliffs, N.J.: Prentice­-Hall, Inc., 1955.

Cronquist, Arthur. The Evolu­tion and Classifications of Flowering Plants. Boston: Houghton Mifflin Company, 1968.

Jeffrey, C. An Introduction to Plant Taxonomy. New York: Cambridge University Press, 1982.

Johnson, Arthur M. Taxonomy of the Flowering Plants. New York: The Century Company, 1931.

Lawrence, George H. M. Taxon­omy of Vascular Plants. New York: Macmillan Company, 1951.

Millspaugh, Charles F. Herbar­ium Organization. Chicago: Field Museum of Natural History, 1925.

Porter, C. L. Taxonomy of Flow­ering Plants. San Francisco: W. H. Freeman and Company, 1959.

Radford, Albert E., William C. Dickison, Jimmy R. Massey, and C. Ritchie Bell. Vascular Plant Systematics. New York: Harper and Row, Publishers, 1974.

Robertson, Kenneth R. Observ­ing, Photographing, and Col­lecting Plants. Urbana: Illinois Natural History Survey, 1980.

Swingle, Deane B. A Textbook of Systematic Botany. New York: McGraw-Hill Book Com­pany, Inc., 1946.

Tehon, L. R. Pleasure With Plants. Urbana: Illinois Natural History Survey, 1958.

Weier, T. Elliot, C. Ralph Stock­ing, and Michael G. Barbour. Botany: An Introduction to Plant Science. New York: John Wiley and Sons, 1974.

Albert G. Mehring, a native of Harrisburg, received his bachelor of arts and master of science de­grees from Cornell University. A member of the Pennsylvania Historical and Museum Commis­sion staff for nearly twenty-five years, he first joined the agency as assistant curator of natural sci­ence. In addition to serving as curator of natural science, he has acted as chief of The State Muse­um’s natural science section for twenty-one years.