A Thief in the Forest
Deep in the moist, shaded coniferous forests of the Pacific coast, a strange, leafless plant called Fringed Pinesap (Pleuricospora fimbriolata) pushes through the layer of decomposing needles on the forest floor. Appearing in the summer, this plant grows to a height of only 6 to 12 centimeters, its fleshy stalk a creamy yellow or white color. It has no chlorophyll and cannot photosynthesize to create its own food. Instead, it survives through a three-way relationship.
This plant is a mycoheterotroph, meaning "fungus-other-nourishment." It acts as a parasite on the vast underground networks of mycorrhizal fungi. These fungi normally have a mutually beneficial relationship with trees like pines and firs. The fungi help the trees absorb water and nutrients, and in return, the trees provide the fungi with sugars produced via photosynthesis. Fringed Pinesap inserts itself into this system, tapping into the fungal network and stealing the nutrients that the fungi have acquired from the host tree. Because it parasitizes a parasite (the fungus on the tree), it is sometimes called an epiparasite.
An Uncommon Flower
The visible portion of the Fringed Pinesap is almost entirely its inflorescence, or flower cluster. The plant's scientific name, fimbriolata, is Latin for "fringed," a direct reference to the finely fringed edges of its whitish sepals. These flowers bloom for only a short time before the plant produces its fruit—a fleshy white berry less than a centimeter wide.
Unlike many related plants that have dry, papery fruits, the Fringed Pinesap's berry is designed for animal dispersal. Small mammals living on the forest floor eat the fruits, and the numerous tiny, sticky seeds are spread throughout the forest in their droppings or on their fur. This plant is native to a limited range, found from British Columbia down to the San Francisco Bay Area, primarily in the coast ranges and the Sierra Nevada. It thrives in mature forests at elevations between 150 and 2,800 meters, where a thick layer of duff supports the fungal networks it needs to survive. Its rarity and dependence on very specific habitat conditions make every sighting a event.