A dedicated group of botany professors and students built an evolutionary model of Wisconsin’s flowers, grasses, trees, and other plants. The effort, funded by a National Science Foundation grant, will contribute to a wider “tree of life” for all North American plants. It also provides clues about the origins of Wisconsin plants and their relationships to other species.

“We have some endangered species in Wisconsin that [have as] their very closest relative an invasive species,” says Ken Cameron, a UW botany professor and director of the Wisconsin State Herbarium. That information can inform conservation officials that invasive species could out-compete the rare species, or that hybrids could create “super weeds” that are resistant to chemicals.

Researchers, including botany professors Don Waller, Ken Sytsma, and Tom Givnish, used State Herbarium specimens, taking a square centimeter of leaf tissue to tease out two pieces of DNA from each species. They started with woody trees and shrubs, sequencing known native plants before moving on to invasive species. The oldest specimens were around 50 years old. A few species were collected in the field.

Wisconsin is the first state in the country to sequence its entire flora in this way, and the UW team hopes to map the results to see how species are distributed and interrelated. Preliminary mapping reveals a few surprises: some of the richest spots of plant diversity are not in remote areas, but instead are found in the heavily urbanized Fox Valley and places just north of Milwaukee.

Lichens are an important part of the world’s ecosystem. They grow slowly but regularly, so they can be used to date major geological and climactic events. Lichens are also important to the diet of a variety of animals such as reindeer. Shutterstock photo.

The Wisconsin State Herbarium has added 60,000 samples to its collection.

Neatly filed away in drawers in the bowels of Birge Hall, tucked into carefully folded slips of paper, you’ll find bits of rare organisms from around the globe. At home within the Wisconsin State Herbarium, they are part of one of the world’s largest lichen collections — a collection that, in 2014, grew 60,000 samples larger.

A herbarium is a group of preserved plant specimens, and Wisconsin’s dates back to the UW’s founding. At the second meeting of the board of regents — in January 1849, a month before the first class gathered — that august group recommended that the university host a “cabinet of natural history.” Today, that “cabinet” holds more than 1.2 million specimens of plants, fungi, and lichens, making it the eleventh-largest herbarium in the Americas.

The Wisconsin State Herbarium’s lichen collection is particularly strong, with more than 180,000 specimens. Lichens are unusual in that they are composite organisms — they develop through a symbiotic relationship between a fungus and algae or bacteria. Each sample includes not only the dried lichen, but also its substrate — the material it was growing on.

Lichens found in the eastern Black Sea region of Turkey. Istock photo.

A scientist who studies lichens is called, not surprisingly, a lichenologist, and in the mid-twentieth century, the UW faculty included the man who wrote the book on lichenology: John Thomson MA’37, PhD’39. (Technically, he wrote the books, plural: Lichens of Wisconsin: American Arctic Lichens, volumes 1 and 2, and so on.) He made the herbarium home to a vast variety of lichens from around the state and across the far north.

In 2014, herbarium director Ken Cameron added 60,000 more specimens when he purchased the collection of German lichenologist Klaus Kalb.

“Kalb’s collection includes mostly specimens from the Old World tropics,” Cameron says. “We had to outbid some big competition — Harvard, the New York Botanical Gardens. But we had a lot to offer, including that we could keep his collection together, and it would round out what we already had.”

The herbarium’s materials are shared with researchers around the world. They can then study how the fungi, algae, bacteria, and substrate interact to create a composite. The UW’s lichens are also available for viewing digitally.