Larcenous lichens

…and some short stories

A big tide-stranded log on the wetlands was studded with lots of little tufts of ‘moss’. It didn’t look a bit familiar to any of us, but I should have looked more closely… a couple of experts later let us know that those tufts are not moss at all. Rather, they are composed of one species of lichen growing on another species of lichen.

Juneau folks see lichens almost everywhere—they drape gracefully from tree branches, form crusts over bare soils, decorate tree bark, boulders, and cliffs with a variety of colors and designs. They can colonize roof shingles, long-abandoned clothing, foam insulation, and other un-natural substrates. And, we just learned, they can grow on each other, too!

Lichens are composite organisms, commonly consisting of a fungus with a green alga, but sometimes associated with a cyanobacterium, or even with both. A given species of algae or cyanobacteria may associate with different fungal partners.  A lichen develops its characteristic shape when the fungus associates with its partner; otherwise, the fungus exists just as a mass of filaments. Does it need the additional input of nutrients from the partners to develop that morphology and to produce spores? Occasionally, other organisms such as yeast (another type of fungus) and bacteria may join the association in some way.

These associations are generally thought to be mutualistic: the fungus provides housing as well as water and nutrients from the atmosphere and sometimes also the substrate, while the other partners provide carbohydrates (by photosynthesis) and cyanobacteria fix nitrogen from the air. In the nutrient exchange between partners, an alga or cyanobacterium is commonly destroyed, but the remaining ones reproduce fast enough to replace the destroyed ones.

Some lichens grow exclusively on other lichens; they are called ‘lichenicolous’ (meaning living on lichens). There are hundreds of species with this specialization, from a variety of evolutionary lineages. It is thought that most of these lichens are parasitic (the fungal partner is presumably the larcenous agent), but some may be pathogens or simply harmless co-habitants.

I had thought to write a whole essay about lichenicolous lichens and their fascinating way of life. I rapidly found out that the arcane taxonomy of unfamiliar names and terminology left me bewildered, so I must content myself with calling attention to an interesting phenomenon that was entirely new to me.

In the case of the tufts on the beach log, a species of Xanthoria was overgrowing a species of Physcia. (But in other regions, different species of Xanthoria may be colonized by a lichenicolous lichen, being the host instead of the invader).  Locally, some other lichen invades the spore-bearing structure of common leafy lichens called lettuce lung (Lobaria oregana) and lungwort (L. pulmonaria), making the structure black. Is the invader hijacking the spore-dispersal mechanism of the host?

Here are a few short stories:

–In a grove near the Boy Scout beach, a friend and I heard a strange, repeated sound. We finally located the source: a porcupine was slowly backing down a fairly tall spruce tree, mostly stepping on small dead branches but occasionally slithering a bit from step to step, moaning every few seconds. Finally it reached the ground, shook itself, and trundled off, still moaning.  Had it been sampling spruce needles near the top of the tree?

Northern Waterthrush. Photo by Bob Armstrong

–One sunshiny morning in mid-May, I happened to look out a window to my pond at just the right time, and there was a northern waterthrush, foraging along the edge. (Despite its common name, this little brown warbler is not a thrush.) I hadn’t seen one for years; later, I heard their loud song, over in the Dredge lake area. They are uncommon nesters here, usually making a cup-nest on the ground, in wooded areas near ponds, where they like to forage in the shallows.

–Later that day, on the lower part of the East Glacier trail, a little group of friends stopped to admire a fine display of small white flowers, several patches of it on a cliff. This species has the very silly common name of Sitka mist-maiden, but bears a more stately name of Romanzoffia sitchensis. It usually blooms a little later than the more famous purple mountain saxifrage, which was still blooming on some cliffs along the trail.

–At Eagle Beach, on one of those sunny days, we saw a nice variety of dabbling ducks, not many of each type, but all clustered in one area near the river. There were gadwalls, green-wing teal, blue-wing teal (not common here), American wigeon, mallards (of course), and a pair of northern shovelers. All these ducks feed on invertebrates and vegetation, often by tipping upside down to reach under the water. Shovelers, however, have an additional way of feeding with a very specialized, broad, flat bill. The relatively large bill is edged with a row of comb-like structures that the shoveler uses to catch small invertebrates and plankton as it sweeps its bill from side to side.

Thanks to Chiska Derr for consultation about larcenous lichens.

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Eating lichens

feeding a diverse group of animals… including humans

Walking along the East Glacier trail one day, I noticed a scattering of gray lichen scraps on the snow next to a small tree trunk whose lichens were the source of the scraps. Some small creature had ripped off much of the lichen, leaving the bits on the snow. A narrow groove led away from the lichens to a small burrow that led down under the snow blanket. That made me think a shrew had been rooting around in the folds of the lichen for insects or spiders, but it was also possible that a small vole had been selectively feeding on the lichen itself.

A few days later, on the Spaulding Meadow trail, I was following some deer tracks, to see where they were going, when my more observant companion called my attention to where the tracks had come from.

There, not far from the trail, there was a noticeable browse line in the arboreal lichens (witches’ hair or Alectoria) hanging from the tree branches, and underneath there was a multitude of deer tracks. All the Alectoria lichens below a certain height, within reach of a foraging deer, were missing from that patch, although they could be found not far away where the deer had not walked.

These observations made me think about lichens as a food source for animals, and I have a very helpful local lichenologist to thank for some great references (as well as instruction on lichen identification). Some lichens are not very tasty, some are actually very poisonous, many have defensive chemicals to deter consumers, and yet a great many critters eat them, often quite selectively.

Somewhere in the world, lichens are eaten by certain snails and slugs, as well as certain kinds of mites and moth larvae; some of these consumers actually specialize on particular kinds of lichen. Although lichen-eating invertebrates have not been well studied in Alaska, we do have a local snail or slug that grazes on the outer layers of leafy lichens. (Recall that a lichen is a composite of a fungus and an alga or bacterium—and some lichens have all three components). Occasionally, if you look closely at the leafy lichens, you might see tiny white trails on the greenish or brownish lichen surface. These meandering trails reveal the white fungal layer below the outer layer, showing where a snail or slug has scraped off the nutritious outer layer that includes the algae or bacteria that also make food for the lichen.

We know a bit more about vertebrates that probably or actually do eat lichens in Alaska.

Caribou are surely the most well-known consumers of lichen all across the North. They use their hooves to dig craters in the snow so they can reach terrestrial lichens, particularly the shrubby, branching ones such as Cladina (reindeer lichens), Cetraria (Iceland lichens), and Stereocaulon (foam lichens), or leafy ones such as Peltigera (pelt lichens). Where there are trees and arboreal lichens, Alectoria (mentioned above) and Bryoria (horsehair lichens) are favorites. Caribou eat lichens all year long, but especially in fall and winter; in spring and summer they consume more willows and herbaceous plants. Apparently, their digestive enzymes change with the seasons, becoming better able to deal with lichens in winter. But lichens are mostly carbohydrate, with low values of protein, so caribou have to find some other source of protein or a means of coping with low levels of nitrogen.

reindeer-lichen-Pam
Reindeer lichen. Photo by Pam Bergeson

Some reports indicate that each caribou has to consume ten or twelve pounds of lichen per day, so a whole herd can make big inroads into lichen populations. Intensive caribou grazing can wipe out whole communities of such lichens, leaving only the low-growing or crust-like ones, and it can take decades for the lichen community to be restored. The most famous example concerns the introductions of reindeer (Eurasian caribou) to St Paul Island in the early 1900s. From just a few animals, the population grew by leaps and bounds, and they ate up virtually all the edible lichens, so their population crashed dramatically. They truly ate themselves out of house and home.

 

In Southeast, Sitka black-tailed deer eat arboreal lichens, as we observed, and so do moose. When mountain goats descend from the peaks into the forest in the winter, they eat arboreal and leafy lichens; in the alpine zone in summer, they may eat branching, terrestrial lichens.

 

There are several species of red-backed voles in western North America and two of them are known to eat both arboreal lichens and branching, terrestrial ones; I found no reports specifically for the species that occurs in Southeast, but it is likely that this species does also. Flying squirrels are important consumers of arboreal lichens (as well as using them to build nests).

 

All these lichen-eating animals are important parts of the ecosystems of Southeast, so it is useful it is useful to consider a few of the ecological interactions that ramify from this lichen base. Some lichens accumulate certain organic pollutants, which are then passed on up the food chain to caribou and deer, and thence to predators such as wolves and humans, where the pollutants become concentrated. Industrial pollution and extensive logging can devastate lichen communities, drastically decreasing the food supply for all of the many consumers. Loss of this important food supply has repercussions in many directions: for example, flying squirrels and voles also eat truffles and disperse the spores when they defecate; truffles are mycorrhizal, making nutrient exchanges with the roots of many trees and supporting healthy tree growth. Caribou, moose, and deer help support predator populations (predators that also prey on other species such as hares and salmon); the browsing of these herbivores can alter plant communities and affect the reproduction of shrubs such as willows and blueberries, which in turn affects bumblebees (that feed on willow and blueberry flowers and go on to pollinate many other kinds of flowers) and birds and bears (that eat blueberries and disperse the seeds).

 

Humans, too, have made extensive use of lichens as food. Indigenous people of the North ate partially digested lichen from caribou stomachs; this material was mixed with fish eggs to make what was considered to be a delicacy (presumably an acquired taste?). In some parts of the world, lichens have been fed to domestic animals, including pigs, dogs, sheep, and cattle, and humans themselves have used lichens as flavoring, thickener for soups, and emergency food.

 

Historically, the biblical manna from heaven, which is said to have sustained the migrating Hebrews in the desert, could have been one of the so-called vagrant lichens, which grow loosely on the ground and can be blown hither and yon by a wind. Many things have been called ‘manna’, including plant resins, honeydew from scale insects and aphids, and certain mushrooms, but vagrant lichens seem especially plausible as the biblical manna, because they would take up water (and expand) after a rain or morning dew, and they can accumulate in some density after a wind (and dew, rain, and wind are all mentioned in one biblical account or another, in association with the appearance of manna). Lichen-manna is quite edible (to humans, camels, and sheep in the Old World, as well as pronghorns in the Idaho high desert) and can be made into bread, but some reports say that it should be eaten in small quantities.

Although lichens seldom claim much of our attention, it should be clear from these considerations that they should not be neglected!

Strolling in the March sunshine

basking and strolling through spring changes

After a deluge in late March, the sun showed itself, prompting residents to enjoy some serious basking. Some baskers took the lizard approach: finding a spot out of the wind and relaxing. Others chose to stroll, in hopes of seeing things beside the insides of their eyelids (mind you, that is quite fine, too!).

One gloriously sunny morning I strolled with a friend out to Nugget Falls on a blissfully ice-free trail. Two mountain goats were visible on the ledges on the far side of the falls, and we spotted four of them on the base of Mt McGinnis, not far above the glacier ice. Juncos were singing from the tops of small cottonwoods and varied thrushes squalled and trilled from the forested hillside. A red bird with white wing patches perched in the alders and gave us a quick look. I thought I saw the crossed bill tips, making it a male white-winged crossbill. But after our stroll we checked the books to pick up other marks for distinguishing these crossbills from the larger and rarer pine grosbeak.

Cottonwood buds were plump and aromatic with that lovely, delicate, characteristic smell that beats any commercial perfume. We found purple mountain saxifrage plants, green and sturdy, but not yet in bloom; just as well, because we’ve not yet seen any bumblebees that could do the pollination.

On the sand flats, lichens have become established. One of the common ones stands an inch or two tall, is white in color, and looks vaguely like small cauliflower heads. This is called foam lichen or snow lichen (Stereocaulon). It and some other lichens are important to the ecological development of these areas, because they take atmospheric nitrogen and ‘fix’ it into a form that plants can use, facilitating the colonization of the area by plants. There are many species of snow lichens around the world, found especially in cold, quite barren locations. They do best in dry, well-lighted places, but at least some species are subject to thermal stress on warm days. They typically are not the very first to move into a barren area, and when the taller vegetation takes over, the habitat is generally not suitable for the snow lichens, and they disappear.

Foam-Lichen,-by-bob-armstrong
Photo by Bob Armstrong

In the afternoon of this sunny day, I went out to Eagle Beach, to soak up some more rays. There was a stiff little north wind, so summer dress was definitely not yet in order. Common goldeneyes dove in the estuary and dozens of Canada geese slept or foraged in the shallows. The usual mob of crows fossicked about on the sands near the edge of the incoming tide.

I tucked myself into a comfortable grassy nook at the upper edge of the beach to contemplate the shining Chilkats. The hundreds of big gulls that had been sauntering along the edge of the sands suddenly got excited and took to the air: hovering just above the water, continually dipping down to the water surface, the whole gang of them slowly moving along the shore for perhaps ten minutes or so. Whatever they were catching was really small—small enough to be swallowed immediately and therefore not big enough to fight over. I’m guessing the prey was juvenile fish of some species, traveling in a big school, but it seemed a bit early for baby pink salmon to be cruising along the shore. Maybe young sand lance?

The weather forecast for the next day was rain, but the sun prevailed in the morning. Parks and Rec hikers trod the Treadwell Ditch trail from Dan Moller to Jumbo, in dappled sunlight. We could see a weather change building up to the south, but the sun was still shining at noon. We were delighted with the new bridges over some badly washed-out gullies, but noted that bikes were leaving deep ruts in portions of the trail. Water levels were low, and we were able to cross Paris Creek: by walking on the mossy dam with the aid of a new rope railing, hopping on wet logs, or stepping on gravel bars and scrabbling over a log jam. If funding comes through, there may someday be a real bridge over this creek.

Going to the dredge islands

eagle bones, lichen gardens, and an octopus rescue

On a fine low tide in late April, I headed out to some of the dredge islands in Gastineau channel, along with two friends. Before we even got to the islands, we found several interesting things. In the middle of the dike trail lay the feathers and other remains of a dead bird. Grazing on the innards were at least twenty little brown slugs—officially known as reticulated tail-droppers. We often see them on bear scats filled with digested vegetation, and gardeners make war on them when they attack some treasured plants, but what were they getting from bird guts?

Just as we left the dike trail, our attention was drawn to a pinkish blob lying in sparse grass. A second look told us it was on octopus, stranded by a recent high tide. An octopus has no business being up in the grass, so after determining that it was still alive, we carefully put it in a plastic bag (from which it tried to crawl out, of course) and carried it with us until we reached some permanent salt water, where it was released and slowly crawled away. It may not have been in very good shape by then, and maybe some disability accounted for its being washed up into the grass, but at least it got a second chance.

octopus-escaping-kmh
The octopus tries to escape its rescuers. Photo by  Katherine Hocker

One island of this chain of islands was a real island before the channel silted up; its core is a forested ridge of bedrock, now surrounded by uplifted land that supports a ring of small spruces and elder berry bushes. An exploration of this island turned up two bird skeletons, minus the skulls; a little forensic work later determined that the bones were very likely those of bald eagles. That made us suspect that they had been shot and left to rot. A sorry thing!

Under some of the trees we found burrows that looked like old otter dens, probably made back in the days before post-glacial uplift increased the distance to permanent water. A cast-up pellet of undigested bits, probably from a raven, held—of all things—the better part of the bowl of a plastic spoon. Overhead, a group of eagles and crows circled peaceably.

We flushed several snipe from the sloughs that cross the wetland. A female harrier coursed in and out of the trees on the smaller islands, probably on her way north (although harriers do nest here occasionally). And buttercups were starting to bloom along the edges of the spruce groves.

Best of all were the lichen gardens on the smaller islands, which are made of dredged sediment from the channel. Sometimes called lichen ‘barrens’, these gardens are barren only of trees and shrubs and tall herbs. They can be a wonderfully artistic spread of color and form. The lichens were very happy, owing to recent rains, so we spent some time admiring the natural art show. We also tried very hard to place our feet where they would do the least damage. Each of these gardens of miniatures was surrounded by a ring of young spruces, lending them a feeling of seclusion and privacy.

On the way back to the car, we spotted a little group of five snow geese, busily grazing—the last reward of a profitable excursion.

Eating lichens

it helps to have four stomach compartments

mountain-goat-kid-2-eating-lichens-by-bob-armstrong
Photo by Bob Armstrong

Mountain goats appeared on the cliffs near Nugget Falls in February, as they often do. My occasional visits to the area have revealed two females and one juvenile, sometimes feeding on alder twigs and once I saw an adult engulf a whole conifer branch. They also nibbled on mosses and lichens close to the ground; we could see that one of their choices was the white foam (or snow) lichen (Stereocaulon).

Here in Southeast, deer, moose, and goats commonly eat lichens, especially in winter when there is no greenery. I’ve seen browse lines in the forest, where deer have munched all the hanging lichens (such as witch’s hair, Alectoria) up to a certain height. Up north, and across the Arctic, caribou and reindeer depend on lichens; in winter they dig away the snow to reach lichens on the ground.

These observations begged the question: What nutrition do lichens provide? Most lichens are low in protein (around two percent) but offer substantial amounts of carbohydrate. Some lichens contain cyanobacteria that fix nitrogen, and these have higher protein value, but they are reported to be less favored by some mammalian lichen-eaters. However, mountain goats are known to eat them. The white foam lichen that the goats by Nugget Falls were eating has about seven percent protein, which is not high, but better than many other species.

Goats, deer, moose, and caribou are herbivores with four-compartmented stomachs adapted to help break down the complex carbohydrates that compose the bulk of the lichens and summer herbage that they eat. A well-developed bacterial flora turns the big carbohydrate molecules into simple sugars that can be absorbed in the intestines. Regional differences in the available species of lichens are accompanied by regional differences in the bacterial flora adapted to these dietary differences. A well-adapted bacterial flora can increase digestibility several-fold.

A now-classic story is that of the introduction of reindeer to St. Matthew Island in the Bering Sea. The Coast Guard had a station there and in 1944 brought in twenty-nine reindeer for an emergency food supply. But the Coast Guard departed a few years later, leaving the reindeer. By 1963 the herd had increased to about six thousand animals. But the population crashed, during the next two years, to just forty-two animals. They had eaten up most of the lichens, and an extremely severe winter, with deep snow, high winds, and low temperatures, quickly finished off thousands of them. By the 1980s, not one was left.

Other mammals eat lichens too. In some areas, horsehair lichen (Bryoria), which is often common on tree trunks and branches, along with certain other arboreal lichens, comprised eighty or ninety percent of the diet of flying squirrels. Red-backed voles eat horsehair lichen and reindeer lichens. These rodents do not have the complex stomachs found in deer and goats, but they must have a good community of bacterial to help digest all the lichen that they eat.

Hordes of invertebrates eat lichen too. There are mites, springtails, small insects, snails and slugs that include lichens in their diets. Sometimes one can see the distinctive scrape marks made by snails or slugs that rasped off the surface of flat, leafy lichens.

Humans eat lichens too, but they often boil it in several waters to remove bitter flavors and cook the lichens in various other ways. These treatments probably improve digestibility as well as flavor.

Lichens are known to accumulate pollutants from the air; in fact, some are useful indicators of air pollution because they sicken and die off in filthy air. They also accumulate radioactive fallout. Even low levels of air-borne pollutants and fallout build up in these lichens, and therefore the animals that eat lichens may regularly accumulate lots of pollutants and radioactivity in their bodies. And then the predators of the lichen-eaters get poisoned too: The wolves and humans that eat deer and caribou, the eagles and ravens that scavenge the carcasses, the owls that hunt rodents, the birds that glean small insects…all of them can accumulate damaging material from polluted and radioactive lichens. In some cases, the buildup of dangerous stuff may be sufficient to change their behavior, impair disease resistance, or diminish their ability to reproduce.

Lichens

often-ignored beings

Our coastal rainforest is characterized by a rich assembly of lichens. Lichens colonize rocks – including the rocky intertidal zone, logs and fallen branches, and even bare sand. They also adorn the trunks and branches of trees. Some branches support numerous kinds of lichens in a sort of miniature garden, of varied colors and textures, often very beautiful.

What, then, are these often-ignored beings? The traditional view is that a lichen is a happy collaboration of a fungus with one or two kinds of alga: a green alga or what was called a blue-green alga, now known as cyanobacterium. Only certain kinds of algae associate in this way with fungi, and only some fungi make these associations with algae. Lichens have been used as classical examples of natural symbiosis (living together), in which the alga provides carbohydrates (by photosynthesis) and sometimes nitrogen (by the cyanobacteria) to the fungus and the fungus provides a protected habitat, water, and perhaps minerals to the alga.

The reality, however, may not always be quite so bland. When the fungus reproduces by spores, which germinate to form a new individual fungus, the new fungus eventually captures algal cells (thus becoming a lichen) and exploits them until they die. Although most lichenizing fungi can live for some time without algae, the algae apparently can live quite well on their own and getting captured by a fungus may not be entirely beneficial from the algal point of view. Thus, many lichens may be viewed as a sort of controlled parasitism of the alga by the fungus. One researcher even commented that sometimes the algae ‘escape’ from the fungal grasp!

The relationship between fungus and alga may vary with circumstances, but the factors controlling that variation remain to be described, it seems. Whatever the precise relationship between the two (or three) different organisms that constitute a lichen, the ecological roles of lichens are important and widespread.

Lichens are important stabilizers of bare ground; in some situations, they help reduce erosion. Indeed, they are said to be the dominant form of ‘vegetation’ on eight percent of the land surface (think especially of Arctic, Antarctic, and alpine areas). They also—very slowly—break down rocks, mostly by secreting acids that weaken the rock, and thus they contribute to the long-term weathering process that creates soil.

lichens-by-bob-armstrong
Crustose lichen on rock. Photo by Bob Armstrong

Ground-dwelling lichens (and mosses) trap wind-blown dust; the dust and associated nutrients, along with nutrients from rainwater, gradually build up soils. Then wind-borne seeds and spores have a good habitat for germination. Lichens containing cyanobacteria can extract nitrogen from the air and make it usable by plants (this is called nitrogen fixation). Foresters in some regions have even encouraged lichens to spread (for example, over a recent burn), in order to improve the soil and make new trees grow better.

Tree-dwelling lichens also extract lots of nutrients from rainwater and fog, and many of our common arboreal lichens are good nitrogen-fixers. Nutrients from these lichens eventually find their way into the soil. For example, we often see, on the ground, fragments of lichens that have been torn from the trees by a stiff wind. When these decompose, their nutrients are added to the soil.

Lichens provide shelter for numerous tiny animals, such as springtails and mites, which are food for spiders and insects, which in turn are food for shrews and birds. We often see warblers, chickadees, and woodpeckers searching among the lichens on branches for lurking insects or spiders.

Caribou have been called lichen specialists. Lichens comprise much of the caribou diet—as much as ninety percent in winter but even in summer about half the diet is lichens. The ground cover commonly called ‘reindeer moss’ is really a lichen. Caribou were introduced to St Matthew Island in the Bering Sea some decades ago; the herd increased rapidly but eventually ate up most of the lichens, which grow too slowly to compensate for the rate of eating them, and thousands of caribou then died of starvation.

Arboreal lichens provide important food for woodland caribou, elk, black-tailed deer, and moose. Mountain goats in our area eat lichens all year long, including several types that grow on trees. Northern flying squirrels and boreal red-backed voles eat a lot of lichen; arboreal lichens may constitute as much as ninety percent of the winter diet of flying squirrels. The flying squirrels also use horsehair lichens to build their nests inside of tree cavities.

Dozens of species of birds incorporate lichens in their nests. I once found a crossbill nest that had blown out of a tree. The outside was made of lichen-covered twigs; in fact, an expert later identified many kinds of lichen in this nest. Hummingbirds commonly decorate the exterior of the nest with bits of leafy lichens, which help camouflage the tiny nest.

hummingbird-nest-1-kmh
Rufous hummingbird nest. Photo by Katherine Hocker

Humans in many cultures have found uses for lichens—as food, fiber, medicine and poison, dyes, decoration, and, in some parts of the world, as perfume. Many kinds of lichen can be eaten; only a few are poisonous. However, they are said to be not very flavorful, at best and are better eaten after boiling in several waters to reduce bitterness or with soda to reduce extreme acidity. The lichen known as rock tripe is famous as a survival food for Arctic explorers. Arctic Natives ate the partially digested lichens from caribou stomachs; this stuff is apparently more readily digested than fresh lichen. Mixed with raw fish eggs, it reportedly formed a favorite concoction (an acquired taste, no doubt!).

Over the centuries, lichens have been used as medicines in various ways, both internally and externally. Some of the rationales for medicinal applications seem ludicrous to us now. For example, lungwort was used to treat lung diseases because its lumpy surface reminded people of lung tissue. However, it turns out the lungwort actually does contain substances that work against TB bacteria. The basis for using a yellow-orange rock lichen to treat jaundice, which turns the skin yellow, is still more tenuous.

Beard lichens contain usnic acid, which has some antibiotic properties. So beard lichens have often have been used in ointments to treat skin infections and sores. Indeed, they have been over-collected in some regions, to the point that they are scarce and hard to find. However, some people are very allergic to this acid, so medicines with this as an ingredient must be used with care.

Fibrous lichens were used in clothing by some Native cultures, mixed with bark fiber. Because such garments were not very durable, they were often restricted to ceremonial use. Branching, shrubby lichens are used in floral arrangements and architectural models to represent shrubs and trees.

Lichens have provided dyes for centuries: in our region they have been used to color mountain goat wool and porcupine quills. Prepared in boiling water, certain lichens yield russets, brown, and yellows. Others yield reds and purples when fermented with a source of ammonia (traditionally, this was stale urine—the aroma eventually dissipated).

An unusual use of lichens is directly applicable in our area. Crustose lichens generally grow slowly, less than a millimeter a year. By measuring lichens on dated (and undisturbed) gravestones, one can estimate the average rate of growth. Then if that estimate is applied to the same kind of lichen on rocks near a glacier or a rock slide, it is possible to estimate how long that rock was available for colonization by lichens; that is, how long it has been there.

Humans have a huge impact on lichen populations and communities. The most obvious is habitat destruction through increasing urbanization. Directly relevant to our area is the dramatic loss of tree habitat when old-growth forest is logged. Second-growth stands support only a much-reduced diversity of lichens.

More pervasive is the dramatic effect of air pollution on lichens, many of which cannot tolerate the pollutants poured forth from industrial processes. Sulfur dioxide is an example of a deadly pollutant, but excess amounts of lead or zinc, for example, could also be detrimental. Some of the most pollution-sensitive lichens include the beard lichens and those that contain cyanobacteria (for instance, lungwort and kidney lichens). The trunks of our red alder trees often look white or grayish, but this is actually a white crustose lichen; in areas with serious air pollution, this lichen dies and the trunks show their brown bark. Because of their sensitivity to air pollution, lichens are extremely useful as indicators of air quality.

A soggy, sorry January

Dreck for hikers, good for fungi and mosses

A dull, dreary, soggy January! Unseasonably warm, and some bears emerged from hibernation. Many of the trails were a mess of mud and slippery roots or hard-packed ice, so ice-cleats were very useful. The lichens and mosses appeared to be very happy, however, as well as some late-fruiting fungi.

On a stroll through the forest, occasionally a small, bright orange or yellow spot attracts the eye. Looking more closely, one can see that they are fungi of jelly-like consistency, growing on dead twigs and branches. The majority of each individual fungus is comprised of long filaments (technically hyphae) that burrow through the decaying wood. The bright color is displayed by fresh spore-producing bodies that release spores when mature, but age turns the orange or yellow to dull brownish. Some species of jelly fungi occur chiefly on dead conifer branches, while others live on dead branches of deciduous woody plants. Another kind is a parasite on other fungi that contribute to the decay of woody plants, frequently growing on the hyphae of the host fungus, inside the dead wood, so it may look like the parasite is growing directly on the wood. Some of these very colorful fungi look rather like tiny golf tees. Others are lumpy blobs or convoluted ribbons, and a blobby species sometimes can look a lot like a convoluted species; two of these, in different genera, bear a common name of witch’s butter.

I thought perhaps I could learn to identify these jelly fungi in the field, at least to genus, without doing the strict mycological method of looking at the spores under a microscope. Ach, not so easy! We have several species of orange jelly fungi. Some seem to be distinguishable to genus (but not to species) even in the field, but others, particularly the witch’s butters, are more difficult. More experience needed!

In addition to the orange witch’s butters, there’s a black jelly fungus called black witch’s butter, a species of Exidia, which grows on the wood of deciduous trees. For me, this begs the question of why these fungi display these colors. Do the pigments serve some particular functions?

Thinking about the common name of these fungi made me wonder about the prevalence of witches in the common names of local organisms. In addition to the ‘butter’, we have witches’ brooms caused by parasitic mistletoe, mostly in hemlocks. And there is witches’ hair, a stringy, tangled lichen that often festoons tree branches and is eaten by deer and mountain goats. And then there are all the things associated with devils, too–devil’s club in the forest understory, and the Devil’s Paw (which fronts the ‘Hades Highway’) and Devil’s Thumb poking up out of the icefield. Hmmm, the practitioners of the black arts seem to be everywhere!

In the same vein–there is a moss called goblin’s gold, which lives in moist, dark little grottos in rocks or under rootwads of fallen trees. It is not very common here, but we found it once. It is luminescent, because special lens-shaped cells in part of the plant capture even dim light, and the adjacent chloroplasts (which contain the green photosynthetic pigment) then gleam a greenish-gold. So a little stand of this moss can, at least to some imaginations, suggest a goblin’s hoard in a small cave. It is not the leafy part of the moss that reflects the light; it is the ‘juvenile’ thread-like part (technically the protonema), which is retained when the moss matures and makes its leaves.

Early February was brightened up a bit by seeing a flock of redpolls foraging on alder cones. I usually begin to see them sometime in February or early March, as they move around from one alder stand to another. They nest in the Interior but irrupt in huge numbers about every other year, moving southward over much of North America in response to shortages of seeds in their northern nesting areas. Smaller numbers probably come to us in Southeast almost every year. They can eat lots of small seeds, such as those of alder, at a time, storing them in an expanded part of the esophagus. Later, they can regurgitate the seeds, remove the husks, and swallow the kernel. Very convenient for keeping a full tummy during the long winter nights.

Thanks to Dr. Gary Laursen, mycologist, for patient, helpful consultation.