Green Reindeer Lichen or Yellow Reindeer Lichen
General – shrub lichen, upright, 4 – 7 cm (sometimes to 10 cm) tall, pale yellowish green, intricately branching from a main stem, not copiously fork-branching from the base; branches hollow, with dull, appressed-cottony surface; end branchlets tending to point in one direction.
Forms mats on ground in open coniferous forest; common and widespread across Northwestern Ontario’s boreal forest; circumpolar.
Tree reindeer lichen (C. arbuscula) is a similar, closely related species. Its branches tend to be coarser, more copiously branched from the base, and more strongly curved in one direction. The 2 species cannot be separated with certainty in the field, but they are easily identified using chemical tests. Prickle cladonia (Cladonia uncialis) is also similar at first glance, but its spreading branchlets and hard, shiny outer surface readily separate it from the Cladinas.
The Woods Cree boiled green reindeer lichen to make a medicinal tea for expelling intestinal worms. The powdered lichen was also taken in water for this purpose. Reindeer lichens provide important ground cover in northern woodlands. Lichens are the principal winter food of many caribou, reindeer and musk-oxen. Although hoofed mammals can survive for several months on a lichen diet, they usually lose body weight because of protein deficiency.
The complex carbohydrates of the lichens are broken down by enzymes produced in the stomach of reindeer or caribou but in few other animals. The bacteria and protozoans in the rumen also help to break down lichen compounds into sugars that the animals can use.
Humans cannot digest lichens and get little energy from eating these plants. However, partially digested lichen from the stomaches of freshly killed caribou was often eaten, and in this form it has much greater nutritional value. In some cases the rumen was mixed with blood and fat, plus meat scraps or liver, to make a pudding, highly esteemed by native people, but usually it was eaten fresh, warm and uncooked. It is said to taste like fresh lettuce salad.
Grey Reindeer Lichen or True Reindeer Lichen
General – shrub lichen, upright, 5 – 8(10) cm tall, greyish white, intricately branching from a main stem; branches hollow, with dull, appressed cottony surface (hand lens); many end branchlets pointed in one direction (swept side to side).
Forms extensive carpets over ground in open coniferous forest (commonly on sandy soils) and in open sites, from lowland bogs on Sphagnum to arctic tundra; common and widespread across Northwestern Ontario’s boreal forest; circumpolar.
Green and grey reindeer lichens are most easily separated by colour. Northern native people used reindeer lichen in medicinal teas to treat colds, arthritis, fevers and other problems. Reindeer lichens were also used as a poultice to relieve the ache of arthritic joints. Reindeer lichens have been taken to treat fever, jaundice constipation, convulsions, coughs, and tuberculosis. Grey reindeer lichen is one of the lichens most frequently grazed by caribou and reindeer.
In northern Europe it was collected as fodder for livestock, in the belief that milk from the cows would be creamier and their flesh would be fatter and sweeter. Grey reindeer lichen is an excellent example of a plant that has adapted to surviving the severe conditions of the north. Stress studies showed that only boiling and radiation caused severe injury to these plants. With a 50% drop in water content, respiration slowed by only 20% and respiration continued until the lichens were almost completely dehydrated.
Reindeer lichens grow slowly, and mature clumps are often about 100 years old. These lichens generally produce a new branch each year, so that age of a clump can be estimated by counting back through the major branchings along a stem. Unfortunately, after about 20 years the lower parts start to decompose and eventually you must make an arbitrary decision as to what is living and what is dead.
Northern Reindeer Lichen or Start Reindeer Lichen
General – shrub lichen, upright, densely branched, usually with no main stem, forming compact, rounded heads (like cauliflower), 5 – 10 cm tall; heads grow singly, in small clumps, or forming billowing mats, yellowish white to pale yellowish green; branches hollow, dull with appressed cottony surface, uppermost branches usually 4 – 6 in a whorl.
On soil, humus or thin soil over rocks, in open coniferous forests, often common in lichen woodlands; widespread across Northwestern Ontario’s boreal forest; circumpolar.
Many of our yellowish lichens, including the yellow reindeer lichens, contain usnic acid. People who are sensitive to this and other lichen substances develop lichen dermatitis, an unpleasant disease with itchy reddened skin, sometimes accompanied by pimples or scaliness. Lichen acids can also cause stomach upset, especially if the lichens are not cooked well. A teaspoon of baking soda in the cooking water may counteract this.
Architects and model railway enthusiasts often colour small pieces of reindeer lichen soaked in glycerine to make lifelike miniature trees and shrubs. In Finland and Scandinavia this is the basis of a million-dollar export industry. Reindeer lichens often form extensive, thick mats on the boreal forest floor. The surface dries quickly, forming a crunchy upper layer, but below this the lichen can remain moist for long periods.
Mats of reindeer lichen can severely limit invasion by other plants. Seedlings that germinate on the lichen mat soon wither and die when the surface dries. Those that do manage tor each mineral soil often become enmeshed in lichen branches and are pulled out of the soil or snapped off by the repeated expansion and contraction of the lichens with changes in moisture.