Rich Hyerczyk and I sat down at a picnic table in Harms Woods to discuss lichens. He had an assortment of books, information sheets, hand lenses, and bottles of calcium hypochlorite and potassium hydroxide to help with species identification. I thought, OK, here is all the equipment, where are the lichens? He pointed at the tabletop. The dark weathering wood was coated with a film of pale green.
You have seen them as green films on wood or yellow patches on tree bark or gray disks on rocks. In areas recently uncovered by melting glaciers they are the first colonizers of bare rock. In more stable circumstances lichens specialize in particular substrates. Corticolous species live on tree bark; lignicolous species live on wood–including picnic tables–saxicolous species live on rock or concrete, and terricolous species live on soils. And, according to Rich Hyerczyk, species that live on reeds are called reedicolous. A little lichen humor.
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It strikes me that Hale’s words provide all the reason anyone would need for getting interested in lichens. Here is a group of organisms familiar enough to grow on picnic tables and fence posts and still so mysterious that we don’t really know the details of how they reproduce.
Wilhelm has been both a mentor in Hyerczyk’s pursuit of lichens and a grateful beneficiary of his fieldwork for his own report, Lichens of the Chicago Region, which is currently in preparation. “A lot of young people think that everything is already known,” Wilhelm told me, “because that’s the way it is presented to them in school. But Rich found an area to work where very little is known. Everything he collected in Putnam County is a new record, because nobody ever looked for lichens there before.”
Meanwhile Hyerczyk continues to collect and continues to find intriguing things. Lichens are usually more common in open sunny areas and less common in shady woods. But when a large oak fell at Black Partridge Woods Forest Preserve Hyerczyk examined the crown of the tree and found 13 species of lichens growing in it. They had been up where the sunlight was. I suggested he needed the sort of rigs used to study the canopies of rain forests. He just smiled. I’m wondering if he might try it.
