A Thief in the Forest
Deep in the humus of coniferous forests across the Pacific Northwest, a strange plant pushes its way into the shaded light. Allotropa virgata, known as candystick or sugarstick, looks like a misplaced piece of holiday candy. Its leafless stalk, growing up to 50 centimeters (about 20 inches) tall, has bold vertical red and white stripes. This plant is a mycoheterotroph, a type of parasite that has abandoned photosynthesis entirely. It contains no chlorophyll, the green pigment that allows most plants to create their own food. Instead, it survives by stealing nutrients from its neighbors, and its target is not another plant.
The candystick's existence depends on a three-part system. It directly parasitizes the underground mycelial network of a fungus—specifically, the matsutake mushroom, Tricholoma murrillianum (often identified as T. magnivelare). This fungus maintains a symbiotic, or mycorrhizal, relationship with nearby conifer trees like Douglas firs, hemlocks, and pines. The fungus helps the tree absorb water and minerals, and in return, the tree provides the fungus with sugars produced through photosynthesis. Allotropa virgata inserts itself into this partnership, tapping into the fungal network and siphoning off the carbon and nutrients that the fungus has acquired from the host tree.
A Unique Biology
Allotropa virgata is the only species in its genus. Its name comes from the Greek allos ("other") and tropos ("direction"), which refers to the way its flowers face outward from the stem, unlike its downward-facing relatives like the Indian pipe (Monotropa uniflora). The candystick's inflorescence is a dense raceme of small, urn-shaped flowers that appear from late spring to mid-summer. These flowers have five white, pink, or brown sepals but no petals. Inside, ten prominent reddish stamens are visible.
The plant's coloration comes from anthocyanin pigments in its stem. Its scale-like leaves are small and do not contribute to energy production. The entire above-ground structure emerges from an underground rhizome with brittle roots that form the parasitic connection with the matsutake mycelium. Even after the plant dies and its seeds are dispersed, the dark reddish-brown stalk can remain standing for several years, a marker of the fungal network below. Its presence is a direct indicator for mushroom foragers that matsutake may be nearby.