Mysterious, Ghostly Plants in the Woods By Susan Camp In late September, I saw several photos on Facebook of an unusual plant called Indian pipe, ghost plant, or ghost pipe (Monotropa uniflora). From midsummer to fall each year, I find several clumps of Indian pipe growing along the borders of our woods, so I went exploring the next day and discovered six clusters of pale, waxy-appearing plants at various stages of development. All were nestled at the bases of beech or pine trees. Many people refer to Indian pipe as a fungus, but it is an herbaceous perennial that doesn’t produce chlorophyll. Chlorophyll is the green pigment in plants that absorbs the sun’s energy, allowing water and carbon dioxide to be converted into carbohydrates for nutrition. Chlorophyll also gives plants their green color, but because Indian pipe doesn’t contain chlorophyll, it appears pale and translucent, almost glowing, in the dark shade of the woods. Monotropa uniflora is found from coast to coast and from Florida to Alaska, with the exception of the Rocky Mountain and southwestern states. It also grows in parts of Asia. This fascinating wildflower grows in the rich, moist humus of deeply shaded mature forests, especially beech, oak, or pine. Each clump of Indian pipe contains several individual 4 to 9 inch tall plants. Each stem bears a single white or pinkish-white, bell-shaped flower. Initially, each flower turns downward. As the plant matures, the flower moves to a diagonal or perpendicular position, which allows small bumblebees to access the pollen inside. Leaves are scale-like in appearance and not readily visible, providing another reason why Indian pipe is mistaken for a fungus. If Indian pipe doesn’t contain chlorophyll and can’t perform photosynthesis, how does it obtain food? For years, this strange plant was classified as “saprophytic” and thought to feed on decaying leaves and forest debris. Now we know that that the secret to its healthy existence is even more complex and fascinating. Indian pipe is a parasitic plant. Parasitic plants obtain some or all of the nutrition they need to survive from other plants. Species of mistletoe are commonly recognized examples of parasitic plants, although, technically, all mistletoe species are hemiparasitic because they contain chlorophyll in their leaves and can produce some food via photosynthesis. Indian pipe, on the other hand, is totally dependent on the kindness of strangers—tree roots, right? Well, it’s not quite that simple. Indian pipe is a special kind of parasite termed a mycoheterotroph that is dependent on a few species of specialized fungi called mycorrhizal fungi. Mycorrhizal fungi join in a mutually beneficial symbiotic relationship with a tree’s roots. The fungi produce a network of structures called mycelial hyphae that extend deep into the soil, becoming an extension of the trees roots. The mycorrhizae provide nutrients and water to the tree; in return, the tree provides food and water to the fungi. This is where Indian pipe enters the picture. It parasitizes the mycorrhizal fungi to obtain water and nutrients from the tree’s roots. In essence, Indian pipe is taking from both the tree and the fungi, and offering nothing in return. Indian pipe is formally called an epiparasite: it is a parasite that feeds off another parasite. Native Americans once used parts of the plant to treat eye infections. It is sometimes used in western herbal medicine. Indian pipe is said to taste like asparagus, but eating the plant is not recommended, as it may contain toxic chemicals. Indian pipe is special plant. It is a rare treat to find a clump, unless you regularly walk in deep woods. Like most wildflowers, it is best to leave them in their chosen spot. They turn dark brown or black when they are picked, and they likely won’t grow in your garden. Indian pipe is a fascinating perennial with complex personal relationships. Read more about this ghostly, mysterious plant in the US Forest Service Plant of the Week entry “Ghost Pipe (Monotropa Uniflora L.)”; at https://forestpathology.org/parasitic-plants/ ; and at https://botany.org/Parasitic_Plants/ . October 29, 2020 .