During the summer of 1968 I investigated the fungal association of Monotropa uniflora L. and of Monotropa hypopithys L. in northern Michigan. In both species of Monotropa there are erect, above-ground flowering stems which from visual observation lack chlorophyll. The underground portion of flourishing plants consists of a compact and roughly spherical cluster of short fleshy roots which grow interwoven with the fine roots of forest trees. ... The fungus associated with M. uniflora in northern Michigan is also parasitic on the roots of adjacent trees as evidenced by its destruction of cortical cells. In all of the specimens examined the fungus was found to be Armillaria mellea, whose rhizomorphs are readily recognizable. On the other hand the fungus associated with M. hypopithys in northern Michigan appears as a component of an ectotrophic mycorrhiza on neighboring trees, although it does not form a completely harmonious association with the tree roots whose cortical cells soon die. The fungus appears to be one or another of several species judging from the morphology of hyphae and fungal strands.