Conopholis americana (cancer root)

At our companion site, MushroomExpert.Com, we get regular "what's this mushroom?" emails asking about Conopholis americana. But cancer root is not a fungus; rather, it is an achlorophyllous plant—meaning that it does not produce chlorophyll and therefore has no green colors. The plant is a parasite on oak trees, and lives underground for several years in the form of knobs attached to the tree's roots; then, in the fourth spring (or thereabouts), it sends up a flowering structure to attract pollinators and reproduce. Thereafter the plant is perennial, lasting about a decade. The plants are fairly tough, persisting each year as brown to black spikes into the summer and, sometimes, the fall.

In Mexico, Texas, and the southwestern states, Conopholis americana is replaced by Conopholis alipna, which is very similar in appearance.

Midwestern range of Conopholis americana
midwestern range

Conopholis americana
cancer root first appears in spring, producing a spike of corn-kernel-sized flower buds

Conopholis americana
plants appear near the bases of oak trees


Conopholis americana
although individual plants are sometimes found, cancer root usually appears in clusters

Conopholis americana
young plants in the spring; notice the eastern newt red eft in the background

Conopholis americana
by fall, cancer root plants are gnarled and blackened

References: GN Jones 1971, RL Jones 2005, Voss & Reznicek 2012, Mohlenbrock 2014, Ackerfield 2015, Hilty 2020, USDA 2020.

Kuo, Michael & Melissa Kuo (May, 2022). Conopholis americana (cancer root). Retrieved from the midwestnaturalist.com website: www.midwestnaturalist.com/conopholis_americana.html

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