Recently I was conducting an interpretive walk at the Trail of 100 Giants in Sequoia
National Forest. I am quite comfortable with the subject manner that normally presents
itself here, mainly of the omnipresent charismatic mega-flora, the giant sequoias. But
every now and then someone stumps me with some related question. Recently it was a 14-
year old girl from Bakersfield who was attending the walk with her classmates and
teacher. "What is this?" the young girl with serious brown eyes asked me, holding a small
clump of green in her hand.
"That is a lichen," I replied. When I saw the look of non-recognition in her eyes I tried to
clarify, "Itâ€™s a combination of two things, really, a fungus and an algae. The fungus is
kind-of like a mushroom and the algae makes food like a plant and they grow together."
This seemed to satisfy her, for a moment anyway. Then she asked, "Do they grow on
rocks?" and I said, "Yes, some kinds do." She asked if the kind she was holding had a name
and I didn't have an answer for her. So I went back home, and like I normally do when a
visitor stumps me, I did some research and found the answer.
The type of lichen the girl brought to me is called a wolf lichen. It is bright neon-green in
color and composed of thin filaments that are all connected together and bunched up in a
clump. It is commonly found in the Sierra Nevada mid-elevation conifer forest.
Sometimes you see it growing on fir or cedar trees, sometimes itâ€™s just laying on the
ground in small clumps. Interestingly, you usually donâ€™t see it growing on giant
sequoias. Perhaps the bark is too soft and flaky for it to hold on to. Wolf lichen is native
to the US and there are several species found throughout the northern hemisphere.
How did it get its name? Well, it turns out this type of lichen is poisonous, and native
people in Russia and northern Europe used it to poison wolves. It is also the most widely
used lichen that native people in North America used for dye. The Chilkat Tlingit people in
southeast Alaska traditionally dyed their prized blankets with wolf lichen. They traded
valuable coastal resources such as fish and shells to groups inland in exchange for the
lichens. There are other types of lichen that were used as dyes as well. In Medieval
Europe the Rocella species of lichen was used to produce a purple dye that became known
as "Royal Purple" as only royalty was allowed to wear clothes that color.
Letharia vulpine is the scientific name for wolf lichen. It is not a type of moss or plant
like most people would think upon spotting it. Remember, not everything that is living is an
animal or plant. There are five kingdoms of life: animals, plants, fungi, algae (Protista),
and bacteria (Monera). A lichen is the combination of two and sometimes three of these
kingdoms of life. One is a fungus and the other is an algae and/or a bacteria.
The fungus is the dominant partner, as it provides the shape and form of the composite
organism, but it is incapable of making its own food. So it has evolved to live with another
organism that can. Most scientists describe the fungi as cultivating algae and/or the
bacteria cells within its structure in order to make food. Lichenologist Tervor Goward
once remarked that, "Lichens are fungi that have discovered agriculture." Algae and some
types of bacteria can photosynthesize and make food which the lichen then uses.
The other creative way of remembering what a lichen is was taught to me long ago and it
usually gets a chuckle out of people I tell it to. "Freddy Fungus took a lichen to Alice
Algaeâ€¦ and now their marriage is on the rocks." Actually, I lied, it usually just makes
people roll their eyes! Oh, well, do with the saying what you will, but I like it.
Lichens come in a huge variety of colors, shapes, and sizes and some are quite beautiful.
There are three main growth forms that lichens exhibit: crustose, foliose and fruticose.
Crustose lichens grow on rocks like a tightly attached crust. They can't be removed
without damage. Foliose lichens are flat and have an upper and a lower surface. Their
lower surface can grow tightly on the rock or tree but they can usually be pried loose
without too much damage. Fruticose lichens may grow upright and look like a clump or like
a miniature shrub (like the wolf lichen the girl brought to me) or they may be hang down
like hair or a beard (like Spanish Moss, which despite its name, is a lichen).
There are more than 3,600 species of lichen in the US and Canada and they grow
worldwide from the arctic to rainforests to deserts. They often grow where conditions
are harsh and nothing else can grow. They are pioneers species growing on bare rock and
desert sand and they often help break down the rock chemically and physically into soil
that other plants can then grow on. They can grow in harsh conditions because lichens are
able to shut down metabolically during periods extreme heat, cold, and drought. When
they do have water, though, they absorb it like a sponge.
Lichens grow very slowly and are thus sensitive to any kind of disturbance. They are
often found in pristine, undisturbed environments and when they are absent it is often an
early warning that something is amiss. They are also sensitive to air pollution and have
been used as an indicator of air quality.
Lichens can be a very important food source for animals. 90% of a caribouâ€™s diet in
the wintertime is made up of lichen. They will claw through snow to get at a patch of
lichen that they can smell beneath it. Deer and mountain goats also eat lichen. Northern
flying squirrels eat lichen and use it for their nests. More than 50 species of birds in the
US also use lichen for their nests.
People can and have eaten some species of lichen as well. Some cultures grind it into a
flour and make bread. Lichen has also been used as a source of medicine since ancient
times. It is estimated that 50% of lichen species have antibiotic properties. Some
cultures steep it and drink it as a tea or grind it and use it in an antibiotic salve. And, who
knew that oakmoss lichen, harvested in large quantities in Mediterranean Europe, is an
important ingredient in fine perfumes? Not me! Until today, anywayÂ¦
Well, I hope that if you're ever at the Trail of 100 Giants, you manage to shift your
attention away from the awe-inspiring giant sequoias, and instead focus on the small
clumps of green you see scattered here and there. Remember to look for the lichen that
is so useful to so many types of animals. Remember that it is also important for people in
so many different ways. Finally, remember that when you see it, it's usually a good sign, a
sign that you're in a healthy environment.
Takin' a Likin' to Lichen
|Wolf Lichen on red fir trees near Quaking Aspen Campground,
Sequoia National Forest, CA
You can tell how much snow this area gets in the winter because
these lichens cannot grow below the snowline on the trees
|Wolf Lichen and an aspen leaf lie underneath a stand of aspen
trees along the Needles Road, Sequoia National Forest, CA
|Some beautiful crustose lichens I photographed in the Mojave
National Preserve last February