Lichens

by Pat Jaquith
pat@westvalleynaturalists.org

One of my passions is wildflowers, but the growing season of wildflowers is pretty short here in the West Valley. I have turned to lichens to help fill the void in colder months; it’s a fascinating venture. Neither plant nor animal, lichens are plentiful around here. One source reports there being 2500 species in the Pacific Northwest. Fossil records date them as long as 400 million years ago. Lichens can be found on the ground, on rocks, and on trees – both decaying and healthy. When you go out looking at lichens, I strongly recommend taking a hand lens because some of their most interesting features are almost microscopic!

A lichen results when a fungus and an alga team up in a mutually beneficial relationship. The fungus provides structural support by wrapping strands of hyphae around the algal cells, and it absorbs nutrients from the substrate. The alga provides carbohydrates produced in photosynthesis, thus keeping the fungus fed. Once classified as plants, lichens are now classified as members of the Fungus kingdom. Lichenologists have divided them into three categories, based on growth patterns: Foliose; Fruiticose (shrub-like); and Crustose.
The lichens below are all foliose lichens (leaf-like).

Umbilicaria/Rock Tripe

Umbilicaria americana (Frosted Rock Tripe) 4.08.17

This leaf-like lichen attaches to the protected side of a rock; its point of attachment looks like a wrinkled spot from the top side. The underside of this lichen is sooty black – you can see a bit of it where it curls at an edge.

Umbilicaria hyperborea 11.19.20

Umbilicaria hyperborea attaches to the exposed side of ledge outcrops; when wet, it has a warty-looking olive green to brown surface; the black spots are fruiting bodies that resemble knots of thread. Moisture is essential to growth of lichens; the exposed side of a ledge dries out rapidly. Lichens absorb moisture (often in the form of fog) over their entire surface, much like a sponge. This picture was taken right after snow had melted when it was in a period of growth. More typically, it resembles wrinkly, dry, glued-on leaves.
Caribou feed on these lichens; it is said to be edible by humans if cooked, but not very nutritious nor tasty. Umbilicaria are regarded as survival food vs. a delicacy.

Pelt Lichens

Peltigera canina (Dog pelt) 11.27.20

The genus name Peltigera is from Greek and Latin meaning ‘shield-bearing.’ Dog pelt often grows in a rosette; its reproductive structures are upright growths (the red-brown protrusions) thought to resemble dog teeth or ears. It was sometimes recommended as a cure for rabies; some thought putting a piece in your shoe would protect you from being bitten by a dog.

Peltigera leucophlebia (Freckle-pelt or Studded leather lichen) 11.20.20

The dark “freckles” are tiny colonies of cyanobacteria that supply the organism with nitrogen. This variety has a veined lower side of the ‘leaf’ as seen on the overturned section here. I first got to know the dry, gray cardboard-like summer version and had to revisit them several times before I could believe the moist version was the same organism! The white granular material on the ground is snow!

Peltigera venosa 11.28.20

This image is a close-up: the tiny green ‘leaves’ are much smaller than they appear. The round discs on the edges are the fruiting bodies where spores will be produced. The underside of P. venosa is veined, similar to the Freckled pelt above. These two lichens grow along the same trail, not far apart, and the feather moss is typical in their locale in coniferous forests.

Lobaria pulmonaria (Lungwort)

Lungwort has always fascinated me with its lobed leaves covering large patches of many of the trees where I see it growing. It seems to be more moisture-dependent than some of the lichens, attaching itself to trees in swampy or streamside environments. Lungwort was so named because it was thought to look like the tissue of lungs; because of the resemblance, it was used as a treatment of pneumonia and other lung disorders. It’s still respected as having respiratory health properties because it only thrives where the atmosphere is clear, but sickens and dies where air is polluted. Thus, it indicates a healthy environment.

Lichens require moisture, moderate temperatures, and sunlight to live. In periods of drought, they go dormant; it is said that many only require a few minutes’ exposure to moisture to begin photosynthesis, and thus growth. I have experimented with wetting them with a bit of water from my water bottle, and the transformation was amazing. Today, December 5, I lingered in an area where conifers were festooned with long tresses of hair (shrub) lichens. In summer, the lichens were pale and dry-looking. Today, they were very green, indicating that photosynthesis was occurring even though the temperature was in the 20’s. With only brief periods of growth, it may take many, many years to attain the size you see. Wanton destruction is not recommended!!

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