species are non-obligate root pathogens, as well as facultative parasites. The genus consists of about 40 species with worldwide distribution that are difficult to identify morphologically. Their hosts include conifers, hardwoods, vines, and even herbs. These fungi contribute to natural thinning and succession of vegetation in forests and decompose wood to develop edible fruiting bodies from spring to autumn. Its genets have a lifespan of up to 2000 years and have been found to occupy as much as 960 ha of forest land. Recently, forest tending work such as thinning of forests has resulted in the creation of tree stumps that support the growth of , and these mushrooms have become an income source in mountainous areas. Therefore, identification of these species is needed. We review the difficulties in identification, suggest a species identification key for Korean indigenous species, and discuss the significance of in terms of forest ecology and plant pathology.