What is the Arthur Herbarium?

With approximately 100,000 specimens of plant rust fungi (Order: Uredinales) from nearly all countries of the world, Purdue University's Arthur Herbarium is one of the world's largest and most studied research, teaching, and reference collections of these kinds of plant parasites. The herbarium, started by Dr. J. C. Arthur, the first head of the Department of Botany and Plant Pathology, has been under development providing scientific services for more than a century. It is the longest continually supported project of the Purdue University Agricultural Experiment Station.

What are Plant Rust Fungi?

The plant rusts form one of the largest natural groups of plant parasitic fungi (6,000-7,000 species), many causing severe diseases of our most important crops. Some examples are: the rusts of wheat, corn and other cereals; forage and range grasses and sugar cane; beans, soybeans, peanuts, and other legumes; various fruits and vegetables; coffee, and forest and plantation timber and pulp trees. Rusts probably attack more different kinds of wild and domesticated plants than any other natural fungus order. Because a rust species is usually highly host specific, i.e. attacking only one or a few closely related plant species, and may have up to six different and dissimilar spore forms and two unrelated hosts while completing its life cycle, the rusts are among the most complicated microorganisms.

Dr. J.C. Arthur
1850-1942

Why are plant rusts important other than that they cause plant diseases?

Rusts are of great scientific interest because of their close evolutionary relationships with their host plants, their complex life cycles, and their numerous biological adaptations that permit them to thrive on all the continents (except Antarctica) under great extremes of environments. Present day rusts represent a very ancient group of organisms whose ancestors were well established parasites on the primitive ferns and fern-like plants of the carboniferous age some 250-300 million years ago. As new kinds of plants evolved, culminating in the numerous species of flowerings plants that now dominate and clothe the earth making human civilization possible, the rust fungi also evolved hand in hand with their new hosts, producing the great diversity of rusts that we know today.

Because of this great diversity and specificity some rusts are now being used and researched as biological control agents for weeds.

What is the goal of the Arthur Herbarium?

The ultimate goal of the Arthur Herbarium is to provide research and reference specimens of all of the world's kinds of rusts that will demonstrate the complete diversity of this group of plant pathogens. From such a collection we can learn more about how rusts are related to each other and to other fungi, their variability in form and function, their complete host range, what they do to their host, and the geographic ranges and limitations of each species. This basic understanding of the natural history of rusts is essential to develop more rational control methods of the diseases they cause or to put rust to work as biological control agents for weeds.

How are rust fungus specimens obtained and preserved in the herbarium?

Over many decades rust fungus collections made during botanical and plant disease surveys by botanists, mycologists, and plant pathologists from many countries and institutions, including Purdue University, have provided the specimens that have built up this growing collection. Rust herbarium specimens are composed of infected plant parts: leaves, stems, flowers, or fruits, that have been properly pressed, dried, and labeled just as are regular botanical herbarium specimens. Such material lasts indefinitely, remaining ready to study, when properly stored and managed. The Arthur Herbarium's oldest specimen is more that 200 years old: it was collected in January 1769 in Tierra del Fuego, Argentina during Captain James Cook's first discovery voyage around the world.

How are rust fungus herbarium specimens studied?

Rusts are microorganisms whose structural details must be studied microscopically. Fortunately, most of these details are preserved by simple drying. Preparations for microscopic techniques and technologies can be used to obtain information. As new kinds of technology develop, they can be used to obtain new information from old specimens.

What are the products and services from work in the Arthur Herbarium?

The main products produced by work at the Arthur Herbarium are scientific papers and books that communicate information and ideas about rust fungi to scientists and students. The specimens in the herbarium are the main source of these data and ideas. Because the specimens remain in the herbarium as vouchers, they can be studied by other scientists, now or in the future, who may accept, reject, or modify the ideas and data presented in the publications.

Experts in the Arthur Herbarium provide rust identification services to an international community of scientists who need authoritative determinations of rusts for plant disease and plant quarantine purposes. The herbarium is an essential reference resource for these services.

Although modern technological improvements aid in securing, managing, and interpreting information obtained from the herbarium, expensive and complicated scientific instruments quickly become obsolete as fast changing technological advancements are made, or they sooner or later are no longer usable and must be replaced. On the other hand, a well managed and used, growing herbarium of specimens becomes increasingly more valuable as a research, reference, and teaching resource as it ages over the centuries.

When the 200th Anniversary of Purdue's Department of Botany and Plant Pathology comes around in 2088 there is no doubt that the Arthur Herbarium will continue to be one of the most important international research, reference, and teaching assets for the sciences of mycology and plant pathology.

Contact Information:

For specimen loans or further information, please contact:

Dr. Gregory Shaner
Interim Director, Arthur and Kriebel Herbaria
Department of Botany & Plant Pathology
Purdue University
915 W. State St.
West Lafayette, IN 47907-2054
Phone: (765) 494-4614
FAX: (765) 494-0363
E-mail: