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Lichens, another kind of flora

2011 October 6
by Robert

Bushy-beard lichen (Usnea strigosa) is a common fruticose form found on trees. Photo by Gary Perlmutter

By Ken Moore
Flora Columnist
Lichens are pioneer plants, colonizers on boulders and other bare surfaces, slowly developing layers of soil particles for the establishment of larger plant communities.

They are diverse and beautiful, and frequently engage us to pause for an admiring closer look, after which, if you’re like me, you most likely move on wishing you knew more about lichens. These are the times we need the company of one of those rare lichenologists, and we are fortunate to have one, Gary Perlmutter, right here in our region.

Gary contributes an introduction to lichens for this week’s Flora:

“Just what are lichens anyway?”

When out in the woods or even in your backyards, you often admire the trees, shrubs and wildflowers. But if you look closer on the trees, rocks and soil, you’ll see little colorful, plant-like things quietly growing on them. They may look like splotches of paint, ruffled leaves or tiny shrubs. These aren’t plants at all, but strange life forms called lichens.

There are at least six species of crustose, foliose or fruticose lichens growing on this boulder surface. Photo by Gary Perlmutter

Lichens are symbiotic organisms, consisting of a fungus and a photosynthetic partner living together as one. I say ‘photosynthetic partner’ because it could be a green alga, which is a plant, or a blue-green alga, which is really a type of bacteria.

My old college buddy Greg who led hikes in northern California would say, ‘Freddy the fungus took a lichen to Angie the algae,’ to describe this unusual type of life form.

Recent research has revealed the relationship is even more complicated, with entire communities of bacteria living inside lichens. Some researchers consider lichens not as individuals but entire ecosystems in miniature.

We lichenologists use the term ‘thallus’ to describe a lichen body. To blur things further, a lichen thallus can be a single lichen or a colony of several lichens merged into one. So the concept of the individual is thrown out the window!

Generally, lichens come in three growth forms or body types: ‘crustose’ (crust-like), ‘foliose’ (leaf-like) and ‘fruticose’ (shrub-like). And they come in a wide array of colors, from black to brown, to green, blue, yellow, orange, red and white. Most are a grayish-green.

Given enough time, lichens grow on just about anything – bare soil, rocks, wood, mosses and even on the bark of trees, from the roots up the trunk and to the canopy branches and twigs. Some lichens grow on other lichens, crowding each other as they compete for light and space. Sometimes if you pick up a fallen branch, you’ll see it’s completely covered with several different kinds of lichens – a community unto itself. In the natural world, you are never far from a lichen.”

Gary, who is engaged in surveying the lichens of the Piedmont region, will lead a one-day introductory class on the identification and weird ways of lichens at the N.C. Botanical Garden on Oct. 15. I’m definitely sitting in on this one. Call the garden at 962-0522 to register and become the first lichenologist in your neighborhood.

Thank you, Gary, for introducing Flora readers to the world of lichens.

Email Ken Moore at Find previous Ken Moore Citizen columns at The Annotated Flora (

The dark squiggly lines on the holly tree trunk are common script lichens (Graphis scripta). Photo by Gary Perlmutter

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