Buckbean -- Menyanthes trifoliata
A muskeg can be a very quiet place. Crossing through, all of the noise seems to be sucked into the mossy mire and I am sunk into thought. These places feel ancient. I am walking in an old basin, once a shallow lake, filled in by thousands of years’ worth of organic matter and sediment, built up, saturated, and compressed into peat under its own weight. The plants of past centuries give way under my own weight, a slight but noticeable spring to the wet ground. Here in southeast Alaska and throughout the northlands where these waterlogged bogs exist, cold temperatures combine with anaerobic conditions to bring decomposition to a near standstill. Slowly, inch by inch, these basins fill in with the withered remains of past vegetative growth. What I am walking on looks much as it did a hundred years ago, a thousand years ago, only more filled in, a little higher. I start to imagine that maybe this quiet is just about the same as it has always been. The buzz of mosquitos provides white noise, a meditative hum linking past and present. Slowly the hum builds and I realized that it is not mosquitoes I am hearing but a manufactured mimic, a distant floatplane whirring up the Lynn Canal. Snapped back to the present, I remember that it is good to be aware. A bear could be around though a likelier problem the ground underfoot, which isn’t always firm. A large muskeg complex is a mosaic of dry and wet land, areas that have filled in completely and spots that are still mucky. Throughout, small streams and little ponds are found. The open water is easy enough to avoid, but areas where a thin layer of moss covers the muck can be less obvious. A step in the wrong spot can put you up to your knee or more. Knowing a little bit about this type of landscape, the topography and plants can help. Ahead I can see hundreds of buckbean (Menyanthes trifoliata) leaf stalks emerging from the moss, a beautiful plant but one to tread near carefully.
Buckbean loves wet places. They are aquatic plants, obligate wetland dwellers, and like other aquatic plants, they require constantly saturated soil around their roots. Where most plants would rot, buckbean thrives. In the muskeg I am crossing, they emerge from shallow open water and the deeply saturated areas surrounding it. These are the mucky places I want to avoid even in my trusted rain boots. Some buckbean has worked its way into a more stable section of the muskeg and I go to see these, picking my steps carefully. What I see is this: a mass of long, bare stalks shooting up to a foot high straight out of the lime green moss that carpets the ground. At the end of these stalks, succulent leaflets in threes like inverted umbrellas opening to receive the sun. The moisture on the moss and in the leaves is dazzling in the sunlight. Beyond the stand of buckbean, like a subtle echo, massive leaves of western skunk cabbage (Lysichiton americanus) mirror what is in the foreground. All of it is framed by the dark green of the shadowed forest at the edge of the muskeg, providing contrast and depth. This world is green, the base color of life.
Over the coming weeks, long Alaskan summer days will work on this buckbean mat. Floral stalks taller than the leaves will emerge, spurred on by the sun and warmth. Clustered at the end of the stalks, numerous buds which will appear pink before and turning white as they elongate into tubular flowers. When these flowers open, petals absolutely carpeted with wiry hairs will be revealed. They are bizarre looking flowers, unkempt, like me. The exact purpose of this hair is unclear but it could be a form of pseudo-pollen meant to make the flower look more attractive to passing insects or a form of defense, making access to the real pollen more difficult for certain less desirable bugs. Whatever the purpose, the result is oddly beautiful and the contrast between the smooth outer surface of the petal and the hirsute inner surface is remarkable.
Just below ground is the secret to buckbean success. Rhizomes, underground stems which are aggressive when happy, allow buckbean to spread through acidic bogs and basic fens, the sopping wet and open peatlands common throughout the north. Buckbean rings the edges of lakes and large streams, filling shallow ponds and creeks with their dense growth. Any open place in the northern hemisphere with saturated soil, long sunny summer days and sustained winter cold, seems to be likely buckbean habitat. The actual extent of their range is almost astonishing. Common throughout Alaska, they also grow from Minnesota eastward through the Great Lakes region to New England. Following the Appalachian Mountains, they sneak down though West Virginia. In the west, buckbean is found in the Rocky Mountains from Montana to Colorado, the Sierra Nevada Mountains of California, and wet mountainous areas of western Oregon and Washington. In Canada, it is abundant everywhere except the dry plains east of the Rockies. Across the Atlantic, you will find buckbean through northern and central Europe, northwest Africa, and Russia. In central Asia, it is home in the Caucasus and Himalayan Mountains, eastward through China and Japan. It is found in Siberia all the way to the coast of the Bering Sea, a short distance from its Alaska stronghold. Except for huge barrier of unsuitable equatorial habitat that rings the globe and hems buckbean in the north, I image it would happily grow in many southerly places as well. Humans brought buckbean to New Zealand, a place to which it is well suited but naturally isolated. Escaping control in its new home, New Zealanders quickly realized the problem and successfully eradicated it, which is an admirable achievement.
The distinctive leaflets, longer than wide and in threes, are vaguely reminiscent of the common garden bean. The resemblance gives buckbean its common name, but it is not actually related to beans. Taxonomically, buckbean is in a league of its own, the only member of the genus Menyanthes. An immense geographic range with plenty of isolated populations makes that impressive. A few factors play into the lack of speciation. First, buckbean relies heavily on asexual reproduction. The rampant rhizomes allow a single plant to cover a lot of ground without having to set seed, but with less reliance on sexual reproduction they have less opportunity for gene mixing and mutation. Second, as with other northern plant species, glaciation has limited diversity. Buckbean habitat throughout the world pretty much mirrors the footprint of glacial ice and the surrounding arctic barren during the most recent ice age. These destructive events create a stark difference in diversity between polar and equatorial regions. Still there is some physical variation in floral structure and overall plant size found between buckbean populations, potential for future speciation. Though it is alone in its genus, buckbean does have a close relative in these same Alaskan muskegs. Deer cabbage (Nephrophyllidium crista-galli), is a member of the same family, Menyanthaceae, and though the resemblance is noticeable, deer cabbage is definitely a toned-down cousin featuring a rounded leaf and ruffle-edged flowers in place of an exuberance of hair.
Both buckbean and deer cabbage flowers feature an interesting morphological adaptation called heterostyly, a trait that limits self-pollination. Individual buckbean plants are genetically predisposed to have either “pin” or thrum” flowers, each plant only produce one type of flower or the other, never both. Plants with pin flowers possess a longer pistil, the pollen-receiving female sexual appendage, and shorter stamen, the pollen-bearing male sexual appendages. Plants with thrum flowers are the opposite, feature shorter pistils and longer stamen. When a bee visits a thrum flower the long stamen cover the bee’s abdomen in pollen while leaving its head, deep in the flower, clean. On a visit to another flower on the same plant, which is sure to be a thrum flower, the pollen on the abdomen of the bee will not come in contact with the female pistil. Only upon visiting a pin flower on a different buckbean plant will the pollen on the abdomen of the bee come into contact with the long pistil. It’s an elaborate solution to the problem of self-pollination. Encouraging cross-pollination allows for greater gene mixing which increases diversity and resilience to environmental changes, important for a species which relies so heavily on clonal asexual reproduction.
Buckbean is used in many different ways by many different people across its range. In China, where it has been used to ease general restlessness and insomnia, it is known by the name shuì cài or 睡菜 which translates to “sleeping vegetables”. The acerbic leaves can be used as the bittering agent in beer making, a once and likely future substitute for hops and something I would love to try. Something I would be less interested in trying is missen, or famine bread, unpalatable but filling and made from carefully processed buckbean root. From what I have read this was truly a last resort food and only for people in the far north where other options were unavailable. There are numerous medicinal applications associated with buckbean, not surprising given that it is pretty closely related to the gentians, a group of plants famous for their medicinal qualities. Among many other uses, dried leaves and roots can be made into a tonic taken to relive indigestion and stimulate appetite, perhaps for missen bread. Like so many herbal remedies, very little testing has been done to establish appropriate dosages and overdosing buckbean can cause vomiting and diarrhea.
In the garden, buckbean would be suitable in a bog or pond planting. I have never seen nor heard of anyone growing it, but I’m sure it is and I did find it available from a few aquatic plant growers. It would certainly make a nice and relatively unique addition to a northern garden. As with other spreading aquatic plants in cultivation it would either require a hardworking, mud-loving gardener to keep it under control, or else a person open to an eventual mass planting. For most people, it is probably best grown in a small wet container. There are so many beautiful little bog plants that would pair well with it in an attempt to recreate the magic of a natural muskeg.
Back in the Alaskan muskeg in early summer, I’m marveling at the masses of white flowers, their intricate design. Among the white is pink of bog laurel (Kalmia microphylla), a small evergreen shrub common throughout this landscape. It’s a simple combination, but overcast skies allow these relatively muted colors to pop. Again it’s quiet and again I’m letting it flow over me. I start thinking about all of the various far-flung places that buckbean, this exact plant, grows and the world suddenly feels smaller.