Monotropa uniflora

It was formerly classified in the family Monotropaceae, but is now included within the Ericaceae. It is of ephemeral occurrence, depending on the right conditions (moisture after a dry period) to appear full grown within a couple of days.

Unlike most plants, it is white and does not contain chlorophyll.[4] Instead of generating energy from sunlight, it is parasitic, and more specifically a mycoheterotroph. Its hosts are certain fungi[4] that are mycorrhizal with trees, meaning it ultimately gets its energy from photosynthetic trees. Since it is not dependent on sunlight to grow, it can grow in very dark environments as in the understory of dense forest. It is often associated with beech trees.[5] The complex relationship that allows this plant to grow also makes propagation difficult.

Like most mycoheterotrophic plants, M. uniflora associates with a small range of fungal hosts, all of them members of Russulaceae.[6]

The stems reach heights of 5–30 centimetres (2.0–11.8 in), sheathed with highly reduced leaves 5–10 millimetres (0.20–0.39 in) long, best identified as scales or bracts. These structures are small, thin, and translucent; they do not have petioles but instead extend in a sheath-like manner out of the stem.

As its scientific name suggests, and unlike the related Monotropa hypopitys (but like the close relation Monotropastrum humile), the stems bear a single flower 10–20 millimetres (0.39–0.79 in) long, with 3–8 translucent petals, 10–12 stamens and a single pistil.[7][8][9][10] It flowers from early summer to early autumn, often a few days after rainfall. The fruit, an oval capsule-like structure, enlarges and becomes upright when the seeds mature, at this point stem and capsule looking desiccated and dark brown or black.

The seeds of M. uniflora are small, ranging between 0.6-0.8 mm in length.[11]

The flowers of M. uniflora are visited by various bee and fly species, most commonly bumblebees.[12] Bumblebees are an important pollen dispersal agent for the plant.

Monotropa uniflora is found in three general distribution areas: Asia, North America, and Central and northern South America. DNA analysis has shown that these three populations are genetically distinct from one another.[1] Furthermore, the North American population and the Central/South American population appear to be more closely related to each other than either are related to the Asian population.

M. uniflora has 48 chromosomes.[13]

The plant has been used as a nervine in herbal medicine since the late nineteenth century.[14]

• Media related to Monotropa uniflora at Wikimedia Commons
• "Indian Pipes, Ithaca NY" is a photo chronology of their development through the season.
• Several images are available from the USDA PLANTS Profile.