Photo by Mike Kling

I find lichen and where they grow particularly fascinating.  

My years of growing bonsai trees has made me aware of many things in nature. This colorful bit of nature is one such thing.

As my trees aged, I often found them on my bonsai.

At one point my interest became the subject of an article which I wrote for Florida Gardening Magazine. 

(Edited with additional photos for this site).

"Who's Painting the Trees"

Many years ago, a friend and I were walking through a heavily wooded area in Key Largo, Florida.

Colorful lichen, not paint, growing in Key Largo Florida

We were there to see a huge old mahogany tree we had heard about.  We found the magnificent tree, but as we continued to walk, we saw bright red stripes.  We honestly wondered “Who’s painting the trees?”

Then I saw yellow splashes and pink tints on other tree trunks. When we looked closer, we realized these remarkable colors were not paint. 

Lichen are unique, rootless organisms. They are the result of a symbiotic association of a fungus and alga.  (More than one type of alga may be present in some forms.)

Symbiosis is the beneficial interaction of two or more organisms, living in a close relationship. There are many such examples in the plant world.  In this case, the alga nourishes the fungus by creating nutrients through photosynthesis. The fungus, which can not create its own food, has the responsibility of providing a body where they both can live. Combined they become lichen.

Often considered a parasitic plant; it is not ... they are not harmful to plants.

What are They Good For?

  • A common food source for animals (such as deer) and some people. Caution though, some are poisonous to humans.
  • A few are used in the production of antibiotics.
  • Some are used as decorative florist “moss”.
  • Dyes for fabric and litmus paper.
  • Perhaps one of the most important uses is monitoring contamination in the air. Most will not grow in highly polluted areas.  When high rates of vehicle emissions or industrial wastes are present, the lichen population will decline.

Three Easy-to-Recognize Shapes

I contacted Richard C. Harris (Research Associate at the New York Botanical Garden) in hopes of identifying some of my photos.  He explained “scientifically identifying lichen is a more complicated process than just looking at photographs.”

"Since they are a combination of fungi and alga, when we see them they are not always in full union. They appear differently when young or mature. Scientists are constantly reviewing forms, debating names and frequently changing nomenclature."

They are also identified by shapes.  The basic shapes are:

  • Crustose, like its name sounds, is ’crusty’;
  • Foliose is ‘foliage’ or leaf like and connects to trees and rocks by small rhizomes;
  • Fruticose appears to be a miniature shrub with tiny branches. It attaches to its substrate by a sucker-looking connector.

The following photos are some of my favorite "finds".

lichen lichen powder-puff-bonsai
Growing on a moist coral rock wall. Encircling branch in the full sun. A "spot" on a 'Frangipani' tree.

Where Can You Find Lichen ?

Trips to forests and parks provide excellent opportunities to view the varied colors and unique shapes.

In Florida, old cypress trees (Taxodium spp.) often have them mixed with the orchids and tilandsia growing on them. Frangipani (Plumeria spp.) and wax myrtle (Myrica cerifera) are especially hospitable to colorful forms of these organisms.

We often think of densely wooded areas as home to these organisms. They are also found in such extremes of climate as the frozen artic and blazing deserts.

If you look closely, you may find them on aged trees, rocks and old logs; and just maybe on some types of bonsai trees in your own garden. I know they were on some of mine.

Over time these organisms have acquired comical common names, like:

rock pimples,

green hair,

earth wrinkles,

angel’s hair,

freckle pelts,

and old man’s beard.

With a little imagination you can add to the list. Discovering these distinctive organisms can be an enjoyable project for children and adults alike.

Where to Go From Here

Lichen is just one of many articles on this site.

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