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--2-David
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!

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