Forest spirits

Indian Pipe, Monotropa uniflora

Speaking of blueberries… while at Maplewood Bog earlier this week I discovered these flowers growing in the forest. It’s one of those species that you recognize right away when you see it, because it’s so distinctive. They are Indian Pipe, Monotropa uniflora, also known as Ghost Plant or Corpse Plant for its pale, almost ghostly appearance, and are completely white because they lack any chlorophyll for photosynthesis. What you see growing above the ground is all there is to the plant – there are no leaves, just these flower stalks. It tends to grow in areas that don’t receive much sunlight, primarily dense forests, and chlorophyll would end up costing the plant more energy to produce there than it would be able to get back through photosynthesis.

Indian Pipe, Monotropa uniflora

So where does it get its energy, if it isn’t producing it itself? There are a number of non-photosynthetic plant species, and most of them are parasitic on another. One of the best known, perhaps, is the mistletoe of western North America, which hangs in the branches of its host tree in large clumps. Indian Pipe appears to be independent, but its host is actually hidden underground. It parasitizes a mychorrizal fungus, which itself is symbiotic with a tree. The fungus helps the tree to secure nutrients and water from the soil, more efficiently than the tree could do on its own. In turn, the tree provides the fungus with sugars that it made through photosynthesis high in the canopy, which the fungus is unable to make itself.

Indian Pipe, Monotropa uniflora

Where does Indian Pipe fit in? While each member of the fungus-tree symbiosis returns something to the relationship, the Indian Pipe is parasitic – it takes, without giving anything in return. It parasitizes the fungus by fooling the fungus into thinking it’s another part of the tree. The fungus gives the Indian Pipe sugars, nutrients and water, but of course the Indian Pipe doesn’t give the fungus anything in return. It can get away with this because it saps a very small volume of food relative to what passes between the fungus and the tree, so neither of the symbiotic partners feels any sort of drain.

dried flower stalks

I had seen many of these dried flower stalks in the forest on previous visits, but without any idea what they were. Now, having seen the Indian Pipe in the same area, I’m fairly certain that they’re last year’s Indian Pipe. After the flowers are fertilized, as the fruits begin to mature, the stalk straightens so that they become erect and upright. Eventually the plant material browns and dies, leaving woody, stiff stems topped with seed capsules.

Indian Pipe, Monotropa uniflora

So what about that mention of blueberries at the beginning? Indian Pipe is actually a member of the Ericaceae, the blueberry family, which includes blueberries and cranberries (of course), as well as rhododendron, azalea and arbutus, among others. Of the 3000+ non-photosynthetic plant species, the majority are in this family. The presence of Indian Pipe in a woodland usually means the soil is very rich and the forest extremely high-quality. If you spot the white flowers there, chances are there are many other unique and uncommon species to be found nearby.