Hundreds of Species Discovered
Remember learning about lichen—that mossy-looking stuff that grows on trees? Probably not, because until recently, lichens barely received mention in high school biology. Now, thanks to the work of Dr. Sheila Strawn, much more is known about lichen and its roles in Oklahoma ecology. Not only has she discovered hundreds of species not previously known in Oklahoma, but she’s also written two books that make understanding and identifying lichen species easy.
So what does lichen do? It is one of Earth’s great recyclers, helping break rocks down into soil and creating fertilizer. In the winter, it can be a food source for elk and bison. Scientists even use the absence of some lichens as an indication of air pollution.
Strawn discovered the world of lichens later in life, getting a Ph.D. in Grassland Ecology after raising her children. She was looking for a research opportunity close to home when she became active with the Oklahoma Native Plant Society.
“I met Pat Foley, who showed me a four-inch-thick book on North American lichens written by a Canadian, but central Oklahoma was largely undocumented. Pat told me, ‘Nobody’s studying lichens in Oklahoma. You wouldn’t be repeating anyone’s research, because it would all be new documentation.’”
After attending a few collecting hikes hosted by the American Bryological (Moss) and Lichenological Society, Sheila and her husband, Steve, who also has a biology background, began driving to out-of-the-way places, climbing mountains, and hiking forests. They discovered lichen everywhere.
Twenty years later, Strawn is the lichen authority for Oklahoma. She enjoys teaching about lichen through her writing, and she was an adjunct teacher at the University of Central Oklahoma until her retirement five years ago.
“I realized a study guide was needed to explain the technical jargon about lichens.” Strawn wrote Lichen Study Guide for Oklahoma and Surrounding States in 2017. Last year, she released a field guide, which identifies 150 of the most common ones in Oklahoma and where to find them. Both books feature the same unique cover, a collage of lichen in the shape of Oklahoma. Edmond artist, Sarah Hearn designed it from her own photographs of lichens.
Goin’ on a Lichen Hunt
“With over a thousand species in Oklahoma, lichens are both plentiful and easy for nature enthusiasts to find. “You can find 20 or 30 different species within a few hours,” Strawn said. “They are always there, day or night, no matter the temperature. They can even survive in outer space. You will never fail to find lichen, sometimes numerous species on one tree.”
Strawn recommends Wichita Mountains Wildlife Refuge and Arcadia Lake as great places to find lichens, especially areas farther from auto traffic pollution. “Lichen is not moss, it has a symbiotic relationship between fungus and algae, which grows on almost any porous surface in the sun; tree bark, rock, and sometimes metal with flakey paint.”
Lichen hunting requires only one tool: some form of magnification. Strawn has found that a cell phone camera works as well as a hand lens for enlarging images. “Viewing lichen close up is all it takes to hook you for life,” Strawn says. “Run your phone up and down a tree with any bark discoloration, especially after it rains and the color is brighter, and you’ll find a variety of species. You can even scrape off a tiny bit to look at later under a microscope. Once you see the small intricate details, you’ll be hooked, too.”