Peterson Lake Trail

slime molds, a berry cornucopia, and a beautiful poison

One bright, sunshiny day in mid August, we checked out the Peterson Lake trail, which is about four and a half miles long, and ends at cabin by the lake. There were rumors of recent trail improvements on the first three quarters of a mile. Indeed, there’s a section with a new base layer of angular, ankle-twisting cobbles, eventually to be covered by finer gravels; then there’s a section of packed dirt and, just before the big waterfall, a smooth section of finished trail.

After the big waterfall (where the steelhead have to stop, in the spring), the trails goes on as it has for years, with a section of packed dirt and slippery ‘corduroy’ logs and then boardwalks through the muskegs. At the Mile 2 marker, a long stretch of mud and roots winds through the forest until the lake finally appears.

The forest was very quiet on this day and no birds were evident, so those of us who are interested in natural history focused nearer the ground. A black slime mold had developed on a log: thousands of individual, independent cells had been feeding on bacteria and fungi in the soil, but now they had gathered together in a single mass for reproduction. Some of the cells will produce spores, while others serve as support structures for the spore-producing individuals. I wonder how they decide which cells will make spores!

The muskegs were dotted with several kinds of ripe berries, including black crowberries, bog blueberries, red bunchberries, and orange cloudberries. I was interested to find a large colony of timberberry in one of the muskegs, with several stems bearing the orange fruit. Timberberry is sometimes called pumpkin berry or, for no apparent reason, bastard toadflax—a name more correctly applied to a different species, but still for no known reason. The name game gets quite confusing, because this plant had been classified in two different genera at different times by different taxonomists. Sigh. The most interesting thing about this plant is that it is a hemi-parasite, drawing some of its nutrition from other plants while also having its own leaves. This is a very versatile parasite, capable of using many host species, such as spruce, alder, willow, currant, bunchberry, horsetail, asters, lupines, and dozens of others.

timberberry. Photo by David Bergeson

The lake level seems to be maintained in part by beaver dams at the outlet. After poisoning many of the resident fish some decades ago, the lake was stocked with juvenile rainbow trout (in the 1960s). A boat by the cabin gives ready access to all parts of the lake.

Along the trail, we noted several late-flowering monkshoods, one of our loveliest wildflowers, which grows at many elevations around Juneau. The complex, bumblebee-pollinated flower is usually a rich purple, although sometimes the purple is streaked with white. A fascinating feature of this plant is that ALL parts are reported to be very poisonous, but perhaps especially the roots and seeds. Eating even a tiny amount of this plant is likely to cause intense gastro-intestinal distress, followed by cardiac and respiratory failure if not treated immediately. And if you handle the plant more than casually, for example by picking leaves or breaking off the stems with your bare hands (not merely brushing by it as you walk), your skin can absorb the poisons. You are then likely to suffer the negative cardiac and respiratory symptoms, but without the gastrointestinal calamities.

The poisonous properties of monkshood have been known for centuries, and extracts of the plant have been used to make poisonous arrows for hunting or warfare, among other deadly uses. On the other hand, as is true of many plant poisons (think of digitalis, for instance), monkshood has also been used medicinally, in small, careful doses. It is a food plant for the caterpillars of several species of moth, which clearly have evolved physiological means of dealing with the poisons. And the bumblebees that pollinate the flowers either find a way to cope or else perhaps the nectar and pollen has less of the poison. Monkshoods are popular garden plants, but it is obvious that gardeners must handle this plant with great care!


Eating poison

toxins as medicine and food

I have reports, from two good observers, of marmots on Gold Ridge eating monkshood, a plant that is known to be highly toxic. In fact, extracts of this plant (genus Aconitum) have been used, historically, by hunters that coated their arrow points, spears, or harpoons with such material, not to mention its use by human murderers. The toxins are very quick-acting, and symptoms begin to appear almost immediately. Although the root is most commonly cited as the principal source, all parts of the plant are said to contain the poisons, and the poisons reportedly can even be absorbed through the skin (although individual sensitivity may vary). That being the case, why in the world would those marmots be eating this stuff? There are a number of possible explanations, none with documentation for this particular case:

Both marmots were observed to be foraging selectively on monkshood, bypassing other plants, and also selecting chiefly the flowers (and incidentally a few of the uppermost leaves). Perhaps the toxins are less concentrated there. Or perhaps marmots have some physiological means of detoxifying the poisons. Or maybe the marmots then eat something that is an antidote (for example, tropical parrots eat toxic seeds and then gather at clay banks to eat the clay that counters the toxins). Possibly the concentrations of the toxin very during the day or at different stages of growth (as is known for some other species). Perhaps there is some medicinal value in small doses of the toxins (as is true for digitalis, for example, used to treat heart problems in humans, but high doses kill). The effects of small doses are variable: small doses might prepare the body’s physiology to deal with subsequent larger doses (‘hormesis’) but small doses of certain compounds may accumulate to lethal levels. Asian medicine features a number of medicinal uses of monkshood, and in some human cultures, the root is even used as food (after boiling in several waters).

Virtually every wild plant, and domestic ones as well, produce (or accumulate substances from the soil) chemical compounds that are poisonous to at least one kind of animal, and often to many species. Many, probably most, of these compounds have evolved as deterrents to would-be consumers. Consumers, in turn, generally evolve counter-measures that render the plant defenses less harmful. In effect, there is a continual co-evolutionary battle between consumer and consumee. Some insects have gone one step farther and sequester the plant’s defensive compounds for their own defense versus predators; in certain cases, these insects have become totally dependent of the kinds of plants that produce particular re-usable compounds. Perhaps the best-known example is the monarch butterfly, whose larvae eat milkweeds and sequester the plants’ cardiac glycosides, which cause digestive upsets in birds that try to eat the larvae or the adults and thus deters predators. (More on this topic of recycled weapons in a future essay.)

Of course, our local flora is full of plants that contain toxic substances, in varying amounts. All members of the buttercup family (such as monkshood) are suspect, wild irises ‘disagree’ with some herbivores, pine needles have been reported to make livestock sick. Consumption of false hellebore (aka corn lily) has nasty results for many kinds of animals. The list goes on!

Mushrooms are known for many hallucinogenic or pathological effects upon consumers. Among the most famous are the Amanitas. Our species is fairly common and quite attractive: the cap is red or yellow, with warty growths that might suggest dots of streusel topping on coffee cake. It is reportedly less toxic than some other species of the genus, but it can produce very nasty effects in humans. Nevertheless, rodents are known to nibble on the mushroom cap: we often see signs of their teeth there. I have not found any reports of the effects of amanita on rodents.

Red squirrel with amanita. Photo by Bob Armstrong

Another local species of some toxicological interest is baneberry (Actaea rubra). It is reported to be highly poisonous– perhaps especially the attractive red (or sometimes white) berries. At least one moth species can eat the seeds, and I recall that, in the Midwest, grouse eat the berries. I once fed berries to several small mammals without obvious deleterious consequences. Nevertheless, for humans, discretion is the better part of valor.

Although there are many studies of the effects of various plant toxins on livestock, it is hard to find reports of plant poisoning in wild, free-ranging animals. The reproductive success of California quail was reduced in years when their preferred forage plants were scarce and the birds ate more plants that contained protective chemicals. Voles in Japan also had lower reproductive success in habitats that contained more plants with certain protective chemicals.

Most cases of poison deaths in free-ranging wildlife seem to be associated with situations where foraging opportunities are limited and the animals don’t have full access to their preferred foods (to which they are adapted). In short, wild animals are usually able to avoid poisoning themselves, unless they have little or nothing else to eat.

That generalization leaves open the question of fruit-eating birds, such as waxwings, that eat fermented fruit and get so drunk that they cannot fly or even perch successfully. They then become very vulnerable to predators and disturbances that might send them crashing into something. Do they eat fermented fruits only when other ripe fruits are hard to find?

Early fall observations

swimming squirrels and a deadly flower

All around town, the maple trees are flaunting their famous reds and golds, at least on certain branches. In the forest, devil’s club leaves are turning yellow, setting off the clusters of red fruits and brightening the understory. Highbush cranberry shrubs sport variegated sprays of red and pink and yellow and everything in between, with the occasional bonus of bright red berries. High on the mountain slopes the deer cabbage offers another colorful palette, of orange and russet and gold. In the valleys, cottonwoods and willows are spangled with gold and yellow amidst the bronzy green—visual treats against the backdrop of somber green conifers.

The sockeye run in Steep Creek is finishing, so the bears are roaming around in search of alternate foods, while they wait for the coho to arrive. Bear scats show evidence of much consumption of northern ground cone, with some devil’s club seeds, currants, and highbush cranberries. The fish are few, but one day I watched a familiar female bear run down a sockeye, pin it to the bottom of the stream, and then pick up the flapping fish and tote it into the woods near the observation platform. There she ate the whole thing except the gills, starting with the eggs; one by one, she also lapped up all the eggs that got scattered around in the grass.

Someone once told me, in no uncertain terms, that red squirrels cannot swim—if you throw one into the water, it will just sink. Aside from the fact that most folks wouldn’t do that in the first place, the statement is simply not true (at least if the animal is unhurt). I once watched a red squirrel swimming between two islands in Glacier Bay. And recently I watched one deliberately cross a creek, jumping right in and paddling across. Its tail didn’t even get very wet and its back stayed dry. A very competent swimmer, across the current of the stream.

Photo by Bob Armstrong

On a walk up the ‘new’ road at Eaglecrest, we found a few late monkshood flowers. No bees seemed to be flying to pollinate them, but we were curious about how the flower ‘works.’ That is, how are the male and female parts arranged, and how would a bee transfer pollen? So we opened up a few flowers. Just inside the natural opening, where a bee would enter, is a tuft of stamens, which would place pollen on a bee as it crawled in. Mixed in among the stamens are the female parts, which would receive pollen. But if male and female parts are in the same place, does this plant pollinate itself or is there some way to avoid self-pollination?

A little bit of research revealed that monkshood species are generally protandrous (first male), meaning that the stamens shed mature pollen before the female part of the same flower is receptive. Bees commonly work from the bottom of the array of flowers, with older flowers, toward the top of the plant, where flowers are younger, so they encounter mature female-stage flowers before they reach the mature male-stage flowers. Before they leave the plant, they pick up pollen from the last-visited flowers. Then, when they fly to the next monkshood plant, they start again at the bottom, where they can deposit pollen from the first plant on receptive female parts of the next plant. In addition, monkshoods are largely self-incompatible: mostly unable to fertilize themselves.

Still to be determined, however, is why the entire flower is so complicated in structure.

Why have that ‘hood’ on top? Those purple petal-like pieces that make the flower are not really petals, they are sepals (parts that are structurally external to the petals; they are green in many other kinds of plants). In the back of the flower, under the hood, are two arching structures that are the true petals, and the nectary is located in a spur at the upper end. But why put the nectary way in back, when the working parts are up front? Bees are said to enter the flower, find the nectar, and then back out the way they came in, passing over the sexual parts as they do so. But the flower does not need to be so complex if that’s all the bees do. Next summer we should try to observe bees as they visit monkshood flowers, to see if we can solve these little mysteries.

By dissecting a few monkshood flowers, we found out that the nectar spurs are quite short, so short-tongued bees should be able to reach the nectar easily, without resorting to nectar theft (chewing through the hood and spur to get nectar without touching the sexual parts of the flower).

But flower handlers beware! Monkshood is very poisonous, and very little of it is needed to produce a nasty effect. Even touching it with your hands and then eating something with your hands, or smoking a cigarette, can apparently have undesirable consequences. Large doses are generally lethal.

One day we walked out toward Herbert Glacier but were thwarted in the last stretch by high water. Along the trail we noted a large white slime mold, artistically draped over a low stump. At several points on the side of the trail were stands of the prosaically named purple coral fungus. It grows in damp soils, sending up finger-like fruiting bodies of a distinctive purple color. It is not to be confused with the unrelated but catchily named deadman’s fingers, which is generally blackish (with a white core) and usually grows on decaying wood. I also found a small specimen of what I think was a white coral fungus. Elsewhere I’ve noted fist- to head-sized clumps of a highly branched yellow coral fungus.