A Bouquet of Lichens

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by Pat Jaquith

Many trees in our area are festooned with lichens of many types. This piece of a branch lay on the snow-covered forest floor as I walked in the Flathead National Forest in mid-November, 2021. What a bouquet! At least four different types of lichen share this short section of wood. Read on as I untangle a bit about them.

Lichens, members of the kingdom Fungi, are a diverse bunch – beautiful and mysterious. In Skip’s earlier post, you can read some of the science about their existence. Three of the lichens on this branch are categorized as Foliose lichens. In summer, when it’s hot and dry, they look crusty and crumbly, appearing to be dried up and dead. Their predominant color is gray. But visit them in a humid environment or in fall or winter when it’s cooler and the relative humidity of the air is high, they seem to have sprung back to life. Their optimal season of growth is when temperatures are below 60 F. Lacking roots, they absorb moisture from their environment through their outer “skin” of fungal cells which becomes transparent when wet; the inner layer of algal or bacteria cells resume photosynthesis, and their colors become visible.

These lichens appear on branches of conifers in moist environments. Often referred to as “puff lichens”, they are hollow – I like to give them a little squeeze. They are light-colored above, and black underneath. The little bowl-shaped disks mounted on short pedestal, called apothecia, are part of the fruiting bodies.They are not always present.

Cetraria Chlorophylla is usually olive-green, like a wrinkled leaf. Reproductive structures are formed of the same material as the leaf on the outside edges. It reminds me of a bronze-colored lettuce variety I grow in the fall. In this picture, it is crowded among other lichens.

On the twig we started with, there is another light-colored lichen appressed to the bark. Above, I have selected two specimens of Hypogymnia physodes which may represent the species that is quite concealed by the leafy cluster of Cetraria chlorophylla in the center of the twig. This species is more tolerant of pollution than most lichens, so it is found along roadsides and in environments where others cannot survive.

Note the color differences between the three Bryoria. The one on the twig at the beginning is very green, thanks to the snow and cool temperatures. These pictures were taken in different seasons. I found the one on the left on the ground and brought it home for more exploration. When it was wet, I attempted to untangle it to measure its length. I found it to be quite elastic and very resistant to separation. Bryoria plays an important – or even critical – role in the winter diet of Whitetail deer. It is high in carbohydrates and contributes to the digestion of woody plants that make up 80% of their winter diet.

Lichens have presented some interesting challenges to me as I attempt to learn more about them. The fact that many of them look so different in their drought/summer mode and growth/wet season mode is a characteristic I still need to remind myself about. I think of them as “Winter Wildflowers” in this northern climate where the season for wildflowers is short. Watch this site for more posts on the Lichen clan!

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