1) Lichens are complex organisms formed from a symbiotic relationship between a fungus and a photosynthetic organism like an alga or bacterium. They come in many shapes and sizes depending on their photosynthetic partner and growing conditions. 2) The document describes several common lichen types found in the Willamette Valley National Wildlife Refuge including leaf-like foliose lichens, branching fruticose lichens, crust-forming crustose lichens, and scaled squamulose and dust-like leprose lichens. 3) Mosses are also described, which differ from lichens in being primitive plants that produce their own food through photosynthesis in

1. Willamette Valley National
Wildlife Refuge Complex:
Lichens and Mosses
Text by J. Bushakra, art by K. Anandakuttan
Whatisthatstuffgrowingontherocksandthetrees?
They are lichens (like-ens). What is a lichen?
Lichens are complex organisms that are a mutual
partnership between a fungus and one or more
light-harvesting (photosynthetic) organisms like
an alga or a bacterium. They occur in nearly
every environment, including the arctic! Foliose Lichens
A common foliose lichen is “lungwort” (Lobaria
pulmonaria). It has a leaf-like structure with
ridges. It ranges in color from light tan to green
to blue-grey. This lichen is found in shady, mixed
conifer and hardwood forests in the Northern
Hemisphere. In this species, the fungus has
formed a mutual partnership with a green alga
and a cyanobacterium (blue-green bacterium).
The close up image shows the spore-producing
structures (apotheca; a-po-theka). These round
to oval-shaped structures are often dark reddish-
brown and are found on the edges of the lichen.
Fruticose Lichens
“Oakmoss” (Evernia sp.) is a fruticose lichen.
This species and others like it can form long,
hanging, net-like structures that are grey-green in
color. These lichens form partnerships with algae.
Lichens are sensitive to air quality and can be used
to identify what impurities are present in the air.The
diversity and abundance of lichens is an indication
of good air quality. Notice the abundance of lichens
on the Refuge – does this make you breathe easier?
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Lichens have five basic shapes: foliose (leaf-
like), fruticose (branching), crustose (crust-form-
ing), squamulose (scaled), and leprose (dust-like).
The different forms commonly grow together on
the same surface. They do not harm the trees.
Lichens are not plants, and so do not have leaves,
flowers, roots or a vascular system to take up
and transport water and nutrients. They are in
the Kingdom Fungi with other mushrooms.
They come in many shapes, sizes, and
colors depending on the photosynthetic
partnership and the growing conditions.
Lichens have been used by humans for food,
medicine and poisons. Please do not eat li-
chens - it can be dangerous. Collecting plant
and animal materials is not allowed in Refuges.
Animals like deer and elk eat lichens. Many insects
look like lichens or use the lichen for camouflage.
Birds such as bushtits and hummingbirds use lichen
to build nests. Like other fungi, lichens eventually
break down the surface they grow on and can colo-
nize almost any undisturbed surface, even plastic!
Crustose Lichens
Sometimes you will see colorful spots on rocks
and trees. These are most likely crustose lichens.
Crustoselichenscanbeanycolorandanysize.They
grow very slowly, about 1/16th
inch per year, as they
get water and nutrients only from the rocks and air.

2. Squamulous Lichens
Squamulose lichens can take on many shapes and
colors. “Tube lichen” (Hypogymnia sp.) grows in
NorthAmericaandismadeupoftube-like,greyish-
green scales with a black underside. When the
lichen is wet the tubes are very spongy, and when
it dries up, it stays dormant until it is wet again!
Leprose Lichens
Leprose lichens really do look like dust or a
scattering of green, yellow, orange, white or grey
dots over the rock surface. Leprose lichens differ
from crustose lichens in that leprose will not form
a “crust” and stay as separate small entities.
Mosses
Wait, you say, what then is a moss?
Mosses are different from lichens as mosses are
primitive plants in the Kingdom Plantae. They
produce their own food through photosynthesis in
their simple leaves. They do not have roots so they
stay small and close to the ground to take up water
like a sponge wicking water. They tend to grow in
mats or clumps and in shady cool places. Mosses
and lichens like many of the same environmental
conditions so you often see them growing together.
AsyouarehikingaroundtheRefuges,seehowmany
different lichens and mosses you can spot. Lichens
seem to have almost infinite variability. Look at
how they grow and on what type of surface. Nearly
every surface has something growing on it! This is
justanotherpartofwhatmakesnaturesointeresting.
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If you want to know more about lichens and
mosses, here are a few resources to check out:
USDA Forest Service website on lichens:
www.fs.fed.us/wildflowers/beauty/lichens/index.shtml
Lichens of North America: www.lichen.com/
The Encyclopedia of Life: eol.org
McCune, Bruce, 2012. Key to the Lichen Genera of the
Pacific Northwest.
Images of British Lichens: www.lichens.lastdragon.org
Basic Moss Biology: bryophytes.science.oregonstate.edu/
page2.htm
“There is a low mist in the woods – It is a good
day to study lichens.” –
Henry David Thoreau, A Year in Thoreau’s Journal: 1851
The size of the lichen patch can give an idea of how
old it is. However, it is difficult to tell if this patch
is all one individual or if multiple lichens grew
together. The only way to know for sure would be
to test the DNA of different sections of the patch!
The drawing above shows two mosses, a star-
shaped mat-forming type (1) and a “fern-like” type
(2). Mosses have a spore-producing structure
(sporangium) that looks like a little brown candle
(3). The top of the “candle” opens to release
the spores. This drawing also shows the spore-
producing structures of a squamulous lichen
growing through the moss (4). The spots on the
dark surface is leprose lichen (5). Here are at least
four different organisms growing together!