Beginning in the 1930s, botanist Edgar T. Wherry worked with his colleagues at the Morris Arboretum on a monumental task: tracking plants growing in Pennsylvania.

Wherry and others examined items already housed in herbariums and collected specimens—both native and naturalized. They labeled and catalogued the plants, and the Pennsylvania Flora Project was born.

The fact that the project had the Commonwealth’s name attached may have simply been for political reasons, says Timothy Block, the John J. Willaman Chair of Botany at the Morris Arboretum, who oversees the Flora Project today.

“Plants, of course, have no idea where the start boundaries are,” says Block. “It just boiled down to working within a manageable unit and in the later years, of course, after plant protection laws were passed, those were done at the state level, and so it still provided a context in which to continue to study what plants were growing where and when.”

Indeed, the study of what is growing where and when continues, but the project has been modernized and is leading researchers in new directions.

“We are also in the process of very actively expanding our vision of what botanical science or what plant science is at the Morris Arboretum,” Block explains.

Some of that involves incorporating modern equipment and techniques into plant research, looking at DNA to answer questions about how plants are related or how to best conserve endangered populations of plants, says Cynthia Skema, a botanical scientist at the Arboretum.

Block and Skema are also filling holes in Wherry’s database by going back to the original specimens and digitizing them. Working in collaboration with the Academy of Natural Sciences, which has the largest collection of Pennsylvania plants, and with part-time staffers and a handful of dedicated volunteers, the Arboretum botanists are taking high-resolution images of the plant specimens and entering all of the corresponding relevant information in a database—from who collected it, to where and when.

“You can have a very terse specimen where you might not have anything other than the locality. Sometimes you just have a collector. Sometimes you don’t have anything,” says Skema. “And then sometimes you can have really verbose labels where the person gives you extreme details about that day and what was there and associated species that were around the plant that was actually collected.”

Skema notes that collectors were both amateurs and professionals, but Wherry and his colleagues at the Arboretum comprised a majority of the database entries.

The numbers in the collections indicate a big digitization task ahead: Block estimates there are around 277,000 Pennsylvania specimens at the Academy alone. The team has imaged 27,000 and has transcribed about 7,000, largely on the backs of volunteers. There are about 35,000 specimens at the Arboretum that have been catalogued but not imaged.

“One thing that we’re happily surprised about is that we had such a very strong volunteer response almost immediately,” says Skema, who notes that Ann Rhoads, retired senior botanist at the Arboretum who literally wrote the book on the subject (“The Plants of Pennsylvania”), has been an active volunteer. “On top of that, we’ve had people who are not botanists and who have not been involved in the PA Flora Project before just step up and say, ‘Oh, this is really interesting.’”

After imaging and transcribing, the third step in the digitization process is georeferencing, which will give users a specimen’s location with near-pinpoint accuracy.

“Part of the purpose of doing this is so that we can understand how things change over time, because nature doesn’t stand still. The distribution of plants in the landscape changes as a result of different environmental influences, and a large part of that has been the human influence on the environment over time,” Block says. “One of the things that makes this really exciting is that the Academy has collections that go back to at least the early 1800s and so once this is all in place … then we should be able to say more about the changes over time.”

Skema adds that having a strong digital collection can be a complement to a physical one.

“Just having all of that information in some sort of searchable database enables us to ask a lot of questions that we’ve never had data for before,” she says. “And that can be everything from climate change questions to evolution of plant form to questions such as how do plants change in cities over time.”

Work on the Flora Project is ongoing, and Block and Skema are waiting to hear if they receive a National Science Foundation grant, submitted with a number of other institutions, to support the work even further.

Skema notes the PA Flora Project ties into larger growth the botany department is trying to achieve, as they work to make the Arboretum the go-to entity in the Philadelphia area for plant knowledge and research. Hand-in-hand with that are efforts to expand courses at the University at-large, which currently include a field botany course in the Biology Department and two classes in PennDesign’s Landscape Architecture Department. They also hope to ramp up the molecular research conducted at the Arboretum, including setting up labs for anatomy-histology and molecular biology.

The PA Flora Project is still at the core of the botany department, says Skema, but “it’s just one part now. There’s a lot growing out of this.”