Stacks and stacks of flattened, dried plants. Each meticulously labeled with a scientific name, collection date, location, habitat details, and other relevant information. Collectively, the over 300 million specimens housed in herbaria throughout the world provide a wealth of information on the world’s botanical diversity and are a rich resource for ecological, taxonomic, and genetic studies. Because location and date are recorded on the specimens, they are an important source of information in studies of past and present plant distribution patterns. DNA can also be extracted from herbarium specimens, and has been used to answer evolutionary and genetic questions. Herbarium specimens have also been used to provide information on changes in plant phenology, i.e., the timing of flowering, fruiting, and other life events, that have occurred over the past couple centuries in response to global change. And they have been used to investigate things that are not directly botanical as well. For examine, leaf damage and other evidence has been used to study changes in herbivory and pathogens. Chemical analyses of herbarium plants have even been used to reconstruct trends in atmospheric pollution. The scientific and educational values of herbaria are varied (for some more examples see here and here), and they will likely be useful for other sorts of investigations in the future.

Index Herbariorum, maintained by the The New York Botanical Garden, provides a global directory of herbaria. Increasingly, information about the specimens housed in these collections has been digitized and compiled into databases so that they can be available for research and education. The process is time consuming and labor intensive, but many herbaria have made all or a good portion of the information about their collections publicly available online. For example, in the northeastern US, the Consortium of Northeastern Herbaria (CNH) provides an integrated portal to search the collections of regional herbaria. Through the CNH portal you can search for records of any species contained in these collections, and if the samples have been georeferenced you can even display the collection locations within Google Maps or Google Earth. For example, here is link to all collections of the the American Chestnut (Castanea dentata) in the database.

The Francis J. Trembley Herbarium at Lehigh University

Recently the herbarium at Lehigh University has been added to the Consortium of Northeastern Herbaria (CNH), although additional specimens are still being entered into the database and many entries still need to be checked. Reorganizing and entering the information about the specimens into a database has been a labor of love, performed by myself and “volunteer” undergraduates (most of the undergraduates that helped had to do this because they missed a course field trip). Data entry has slowly progressed since I first unearthed the herbarium from the basement of Williams Hall in 2010, and is now more than 90% completed. I have added my personal herbarium collection as well, and the Francis J. Trembley herbarium now serves primarily as a teaching resource, although plenty of research opportunities exist. The addition of the herbarium to the CNH makes it more accessible for research, as now this “virtual herbarium” is publicly available.

The collection is small in comparison with the large herbaria of the world (see here for a list of the largest herbaria), only containing about 2200 specimens. However, collectively small herbaria contain a large number of plants; furthermore, small herbaria oftentimes contain important regional collections and the collections of important scientists. The Lehigh University Herbarium includes the collection of Francis Trembley, a pioneering professor of ecology at Lehigh University. His plants were primarily collected from eastern Pennsylvania in the 1930s. The collection represents about 200 plant families and over 500 genera. Below are some figures showing some other characteristics of the collection.

Searching for specimens in the herbarium

To search for specimens in the herbarium, go here. You can search by collector last name, genus, species, location, or other fields. For example, here is a link to all the specimens collected by the herbarium’s namesake, Francis Trembley, and here is a link to all of the specimens he collected in the old Lehigh Arboretum (see here for more information on the arboretum). Or perhaps you want to know what specimens were collected in Pennsylvania, New Jersey….or even Alaska. Or maybe you are interested in plants of the Okefenokee Swamp in Georgia, or you are student in my wetland ecology field course 🙂 and want to see what species have been collected in Pymatuning Creek Marsh in western Pennsylvania. Of course, you can also search the entire CNH database, including Lehigh’s collection and other regional herbaria, by going here.

Future plans and new specimens

The remaining specimens in the herbarium will hopefully be made “virtual” in the coming months. Samples from the Northeast will also be georeferenced so that they can be plotted geographically, and eventually images of the herbarium sheets will be uploaded. At this point, few attempts to update taxonomy have been made and the specimens are organized based on the original species identifications. However, it appears that synonyms can be searched through the portal, although I have not experimented with this yet.

Of course, new collections will also be added. Plant collecting is a great way to learn plant identification, and archiving the specimens in herbaria contributes to our knowledge of the world’s botanical diversity. And besides, there is just something fulfilling about standing on a full plant press, pulling the straps to tighten it, and feeling the crunch of cellulose compression beneath your feet.