Ada Hayden Herbarium (ISC-IA)

Overview: The Ada Hayden Herbarium (ISC-IA), in the Department of Ecology, Evolution, and Organismal Biology at Iowa State University, is by far the largest herbarium in Iowa and one of the 15th largest university herbaria in the United States. The herbaria at Iowa State University (formerly Iowa Agricultural College and Iowa State College, ISC) and the University of Iowa (formerly State University of Iowa, IA) were each founded in the 1870s. Both universities had active Botany Departments and renowned faculty well into the 20th century. However, by the 21st century, Botany at the University of Iowa was in decline, and in 2004, the Herbarium (IA) was transferred to Iowa State University. The Ada Hayden Herbarium grew from approximately 430,000 specimens prior to the transfer to more than 650,000 specimens today. Strengths of ISC-IA include vascular plants of Iowa and the Midwest United States, Poaceae of the Western Hemisphere, Fabaceae of the contiguous United States, bryophytes, and fungi. Staff are actively engaged in research, teaching, curation, digitization projects, and outreach.

With Iowa being the most biologically transformed state in the United States, ISC-IA takes on added significance of recording the flora of Iowa’s past. The collections not only serve to document studies of the past or provide context for Iowa’s natural and cultural history, or even to document what was lost, but they also inform restoration efforts, target rare species for which to search, provide a measure of the quality of remnant sites and more. ISC-IA more broadly fulfills the value of herbaria in research, teaching, preservation, and documentation.

History of ISC [date ranges in parentheses indicate years on staff]—Iowa Agricultural College (IAC) opened its doors to students in 1868 as Iowa’s land-grant college. Time spent at IAC launched notable botanical careers of a number of its faculty and graduate students. Norton Townshend (1868–1869) spent one year at the new college, teaching botany and geography. Although a popular teacher, he returned to his home state of Ohio to help charter Ohio State University (then Ohio Agricultural and Mechanical College). In early 1870, Charles E. Bessey (1870–1884) joined the faculty as Professor of Botany, Horticulture, Zoology, and Entomology (Fig. 1). In his biennial report to the College administrators in 1871, he stated that the Herbarium contains “representatives of perhaps about 2,500 species.” Joseph C. (J.C.) Arthur was one of Bessey’s earliest and most outstanding students. Arthur was in the first graduating class in 1872 and was the first to receive a Master’s degree from Iowa Agricultural College in 1877. Arthur (1876–1877) was an instructor while at the College, helping to take on some of Bessey’s heavy teaching load. In 1876, Bessey and Arthur prepared an exhibit of Iowa plants and woods for the nation’s Centennial Exposition in Philadelphia. Arthur also published a catalog of Iowa’s flowering plants in 1876: “Flora of Iowa: A Catalogue of the Phanerogamous Plants.”

In 1884, Bessey left IAC to become Dean and Professor of Botany at the newly opened University of Nebraska. The herbarium contained approximately 15,000 specimens at the time Bessey left the College. He was replaced by Byron D. Halsted (1884–1888), who, it is reported, “did not add much to the Herbarium in the way of flowering plants, but he added a considerable number of fungi.” However, Halsted did help train another student who became a prominent botanist, Albert S. Hitchcock. Hitchcock first studied with Bessey and received his B.S. in 1884. He continued his studies with Halsted and earned his M.S. in 1886. He remained at IAC as an assistant in Chemistry until 1889, and during this time, he conducted a study of the flora of Ames and central Iowa.

Louis H. Pammel (1889–1929) arrived at IAC in 1889, and his botanical and mycological interests were broad (Fig. 2). As a collector of both plants and fungi, he contributed the largest number of specimens to the Herbarium —likely more than 25,000. He welcomed the first African-American student, George Washington Carver, to IAC. Carver received his B.S. at IAC in 1874 and his M.S. in 1876, just before heading to Tuskegee Institute (now Tuskegee University). While working on his M.S., Carver was an instructor in the Botany Department, and he collected more than 300 vascular plants and 160 fungi while a student (Fig. 3). He lacked a herbarium during his early years at Tuskegee, so sent about 450 additional mycological specimens to ISC from his plant pathology research in Alabama.

Ada Hayden (1911–1950) was another remarkable student of Pammel’s (Fig. 4). She received both her B.S. and Ph.D. degrees at Iowa State University. In 1918, she became the first woman (and only the fourth of either gender) to earn a Ph.D. at Iowa State and one of the earliest women to receive a Ph.D. in Botany in the US. Hayden was promoted to Assistant Professor after receiving her degree, and later named as Curator of the Herbarium in 1934. She added more than 16,000 specimens to ISC, and the quality of her specimens, both in care in pressing and in label data, exceeded that of her predecessors and colleagues. Concerned about the loss of Iowa’s prairies, she pushed for the establishment of state preserves. Three prairie remnants were purchased by the state by the time of her death in 1950, and one of these is named in her honor.

Richard W. Pohl (1947–1986) became ISC’s Curator following Hayden’s death in 1950 (Fig. 5). He had come to Iowa State as an agrostologist; his collections of grasses, along with those of his students, from the western hemisphere made ISC one of the outstanding university collections of Poaceae. In 1984, Deborah Q. Lewis (1984–present) was added to the staff as a full-time Curator to manage the growing collection. Pohl then held the title of Director of the Herbarium until his retirement in 1986.

Duane Isely (1944–1989) arrived at Iowa State as an Extension Associate and Assistant Professor in seed technology. His interests soon shifted to the Fabaceae, and he collected more than 15,000 legume specimens from across the contiguous United States. Not only did he explore all 48 states, but he also claimed to have visited well over 90% of the counties in these states during his studies! He assumed the directorship of ISC on the retirement of Pohl, a position he held until his retirement in 1989.

Lois H. Tiffany (1950–2003) was a graduate student of Joseph C. Gilman (1918-1966), earning her Ph.D. in 1950 (Fig. 6). She then joined the faculty as a mycologist and eventually became ISC’s Curator of Mycology. More than 8,600 of her fungal and lichen specimens are in ISC, and her graduate students added many more.

Lynn G. Clark (1989–present) was appointed as the Director of the Herbarium to follow Isely, and she continues in this position. She had received her Ph.D. from Iowa State as a student of Pohl. The field work and collecting that she and her graduate students have done in their studies of the bamboos (Poaceae: Bambusoideae) have added further prestige to ISC’s Poaceae collection.

History of IA—The earliest history of the founding of IA remains a mystery, with geology professor Charles A. White (1867–1873) having referred to the “State University of Iowa Herbarium” and listed a few plant species collected as early as 1869 as part of the report of the “Cabinet of Natural History.”

Extant specimens indicate the establishment of IA in 1878, with collections made by botanist and mycologist Thomas H. Macbride (1878–1916). The State University of Iowa’s (SUI) Botany Department was initiated under Macbride’s guidance. His extensive collections of Myxomycetes are primarily at BPI, although a smaller subset remains in ISC-IA. In 1893, the British Museum sent reportedly about 30,000 vascular plant duplicates to IA in exchange, apparently for Macbride’s duplicate Myxomycete specimens (Macbride, 1912). Many of these specimens are the oldest held in ISC-IA (Fig. 7). Macbride spearheaded the establishment in 1909 of Iowa Lakeside Laboratory near Milford, Iowa. He and Pammel proposed and pushed for the establishment of Iowa’s State Parks system, and the first State Park (Backbone, near Strawberry Point) was dedicated in 1920. Macbride and Pammel State Parks honor their legacy.

Bohumil Shimek (1890–1932) was added to the Botany faculty to assist Macbride (Fig. 8). He was appointed as Curator of the Herbarium in 1895, and he held this position until his retirement in 1932. More than 20,000 vascular plant specimens and 3,000 bryophytes and fungi document his diverse interests and contributions.

A few years after Macbride retired from SUI, George W. Martin (1923–1955) joined the faculty as a mycologist. Although his mycological interests were broad, he teamed with Macbride, and later with C.J. Alexopoulos, in stud ies of the Myxomycetes that resulted in the definitive reference books for this group.

William A. Anderson (1931–1949) was named Curator of Vascular Plants at about the time that Shimek retired, a position he held until his death. After retiring from Grinnell College, Henry S. Conard (1944–1954) brought his large collection of bryophytes, as well as some vascular plant specimens, to IA as a Visiting Research Professor. He spent the next decade curating his own collections, as well as those collected by Shimek.

Robert F. Thorne (1950–1962) joined the University of Iowa (UI) faculty and succeeded Anderson as the Curator of Vascular Plants. His dream of producing an Iowa Flora ushered in a new era of plant taxonomy at the University. He and his students accomplished both floristic studies of counties and regions of Iowa and those of plant families occurring in the state. Unfortunately, this project had not been completed by the time he left UI for Rancho Santa Ana Botanical Garden and Claremont Graduate University.

Thomas E. Melchert (1963–1982) was named Curator of Vascular Plants following Thorne’s departure. Robert L. Hulbary (1963–1981) assumed the role of the Curator of Bryophytes. During this time, some of IA’s holdings were dispersed, including most of the Myxomycete collection (approximately 8,500 specimens) sent to BPI and the entire lichen collection containing more than 5,000 specimens sent to MIN.

The last Director of the Herbarium and Curator of Vascular Plants and Bryophytes was Diana G. Horton (1983–2004, as Director). She focused her efforts on floristic studies, including Iowa’s rare species, and mosses.
Transfer of IA to ISC—The transfer of IA’s holdings to ISC began in 1984 when approximately 25,000 mycological specimens (including the remaining Myxomycetes) were moved to ISC on permanent loan. In 1989, more than 1,500 specimens of IA’s algal holdings were also shipped to ISC.

In 1999, IA Director Diana Horton contacted ISC Curator Deborah Lewis, posing the question of whether ISC would be willing to accept the remainder of IA’s holdings if IA were forced to be transferred off-campus. In early 2002, ISC Director Lynn Clark was told by UI administrators that IA would not be maintained at UI. Reasons that were given included that IA was located in space that would be renovated and claimed by another UI department, and there was no room for IA in the Biological Sciences Complex. It was also a time when the Board of Regents of Iowa’s public universities was pushing for a reduction in duplication of programs between the universities. Other issues included the precedent set by past divesting of holdings, a lack of strong constituent support, a shift in departmental priorities, a lack of transparency in decision-making, and a lack of a timely response to issues raised by the proposed transfer.

A Memorandum of Understanding concerning the transfer of IA was signed by administrators at both universities in July, 2002. Work commenced to update the facilities of ISC to be ready for the transfer, including the installation of a mobile storage system, funded primarily by the Iowa State University Foundation (Fig. 9). As the time for physically moving the collection drew near, a civil case was introduced by faculty, students and alumni of UI in Federal District Court on 26 February, 2004, to block the transfer. When the first attempt was made to pack and move IA in early March 2004, a restraining order was issued to halt the activities. After a court hearing, this injunction was lifted, but the civil case remained undecided. Finally, in June, 2005, the case was heard and in late August, the judge’s ruling was issued that the transfer would stand (Fig. 10).

Several important lessons were learned from the transfer: (1) Take any perceived threat seriously. Despite a long affiliation with a university, it should not be taken for granted that natural history collections, including herbaria, are immune from such actions. (2) Be proactive instead of reactive. Promote active use of the collections in research and teaching and as a resource for depositing specimens to as many constituencies as possible. (3) Make colleagues, administrators, students and the public aware of the significance of herbaria and natural history collections through tours, presentations, news articles and in other venues.

Special collections in ISC-IA—Charles C. Parry arrived in Davenport, Iowa, in 1846 to set up his medical practice. However, while medicine was his career (at least early on), botanical exploration was his passion. As an early collector in the western US and northern Mexico, he amassed a collection of more than 15,000 specimens from his own studies and exchange with his colleagues (Fig. 11). Following Parry’s death, Pammel arranged for the purchase of the C.C. Parry Collection containing specimens, field notes, correspondence and library in 1895 for $5,000. Progress is being made on digitizing this collection, which is rich in types.

The Andrew Price (A.P.) Morgan and Laura V. Morgan Mycological Collection was donated by Laura Morgan to IA in 1909 and is also held as a separate collection in ISC-IA. The specimens collected by A.P. Morgan (and some jointly with L.V. Morgan), mostly in Ohio, have been digitized and are available in MyCoPortal. The beautiful and detailed gouache paintings of fleshy fungi by L.V. Morgan are currently being curated and digitized as well (Fig. 12).

The John Dodd Diatom Collection contains more than 6,000 microscope slides of diatoms collected by Dodd (approximately 1950–1982) and his students, beginning in 1960. These slides represent studies of diatom ecology in Iowa, resulting in publications and dissertations.

The long history of botanical and mycological research at ISC and IA, as well as exchange and gifts for determination from other institutions has allowed the accumulation of a significant number of types. The ISC-IA Types Collection contains approximately 1,200 vascular plants and 1,100 nonvascular plants and fungi. Most of the vascular plant types have been digitized with records available in the Global Plants Initiative Types project (, and those for the fungal types available in MyCoPortal (

Until 2003, ISC held the Jacob Peter (J.P.) Anderson Alaskan Collection, containing approximately 30,000 specimens. After receiving his B.S. at Iowa State in 1913, Anderson spent 27 years in Alaska, studying and collecting the flora while owning and operating the first florist business in the state. In 1941, he returned to ISC with his large collection to complete nine parts of his Flora of Alaska before his death in 1953. Stanley Welsh added thousands of additional specimens to the collection as he worked to complete Anderson’s Flora, and Anderson’s Flora of Alaska and Adjacent Parts of Canada, by Welsh was published in 1974. The collection was transferred to ALA to provide space to accommodate the holdings of IA.

Recent and current projects and activities—The combined holdings of ISC-IA provide the most comprehensive primary source of plant, fungal and lichen diversity and distribution information in Iowa. The holdings also document studies by ISC-IA faculty, staff, associates and graduate students, including those of the following: Lynn Clark’s lab—Poaceae, especially bamboos (Fig. 13); Jonathan Wendel’s lab—Gossypium and its relatives (Malvaceae); Donald Farrar—Botrychium (Ophioglossaceae); John Nason’s lab—Ficus (Moraceae); Mark Widrlechner—Rubus (Rosaceae); James Colbert’s lab—Iowa’s lichens; and Deborah Lewis and collaborators—Iowa flora. Floristic projects are also being carried out by others, including citizen scientists across the state, resulting in additional voucher specimens being added to ISC-IA.

Ongoing studies of the Iowa Flora: Lewis continues to host a series of meetings with botanists from around the state to accomplish two goals: the initial goal was to update the coefficients of conservatism for each of Iowa’s native species of vascular plants for use in floristic quality assessments of sites as developed by Floyd Swink and Gerald Wilhelm (1994). However, as the team evaluates each species, the status of identity, name, synonyms, and more is also checked in current literature so that the species list for Iowa can be revised as well. Clark is revising keys to Iowa’s vascular plants; while this is being undertaken with students in her Plant Systematics course in mind, these keys are also an important addition to efforts toward a state flora.

Digitization projects: ISC-IA has participated in two NSF-funded Advancing Digitization of Biodiversity Collections (ADBC) Thematic Collections Networks (TCNs): (1) Plants, Herbivores, and Parasitoids: A Model System also received for an additional NSF-funded project to digitize the bryophyte holdings and from USDA for digitizing records for USDA Plants. This support has allowed many of ISC-IA’s specimen records to be made available online, although work continues on these projects. ISC-IA’s data have been added to the SEINet Consortium of Northern Great Plains Herbaria Portal (vascular plants), Mycology Collections Portal, Consortium of North American Bryophyte Herbaria Portal and Consortium of North American Lichen Herbaria Portal.

Contributions by volunteers: Lastly, the work and contributions to ISC-IA and to botanical studies in Iowa by citizen scientists and volunteers are gratefully noted. Two volunteers, Jean Day and Robert Nicholson, have assisted with curatorial tasks for more than a decade. Student volunteers have helped with digitization projects. Jimmie D. Thompson, a citizen scientist affiliated with ISC, is currently one of the most prolific collectors and contributors to ISC-IA, as well as being an author or coauthor of six publications on the central Iowa flora. The support provided by all of these promotes ISC-IA’s visibility and relevance.

Links to resources on the Ada Hayden Herbarium website:
The Ada Hayden Herbarium website ( will soon be updated. However, it currently has links to useful information and resource pages (hopefully also updated in the near future) for a number of taxa.

Grasses of Iowa —
Bamboo biodiversity —
Moonwort (Botrychium) systematics —;
The Iowa lichen project —
Iowa fungi species descriptions —

Literature Cited
Horton, Diana G. and Paula Bergstrom. 2006. History of the University of Iowa Herbarium: A Legacy Lost.
Lewis, Deborah Q. and Lynn G. Clark. 2018 (updating in progress). Ada Hayden Herbarium – ISC.
Macbride, T.H. 1912. Twenty-five years of botany in Iowa. Proceedings of the Iowa Academy of Science 19: 43-63.
Swink, F. and G. Wilhelm. 1994. Plants of the Chicago Region, 4th ed., Indiana Academy of Science, Indianapolis,
921 pp.