The taxonomy of annulate [possessing a ring-like structure on the stipe (stem) of the basidiocarp (mushroom, fruiting body, basidioma) that is the remnant of the ruptured veil on the underside of the cap] Armillaria (Figs. 20.1E-J, 20.2, and 20.3) and its exannulate (without an annulus) sister genus Desarmillaria (Fig. 20.1K) is constantly changing. However, at least 40 species are currently recognized around the world (Baumgartner et al., 2011; Koch et al., 2017; Heinzelmann et al., 2019; Antonín et al., 2021; Kedves et al., 2021), and most Armillaria spp. have a wide host range. In many cases, species of Armillaria are distinct between the Northern and the Southern Hemispheres. Historically, the identification of Armillaria was largely based on the morphology of the basidiocarp, and interfertility or mating compatibility (e.g., Korhonen, 1978; Anderson and Ullrich, 1979; Heinzelmann et al., 2019). In recent decades, recognition and identification of Armillaria species has become increasingly reliant on DNA sequences, such as phylogenetic analyses representing multiple gene regions, which elucidate the evolutionary relationships among the species (e.g., Guo et al., 2016; Klopfenstein et al., 2017; Koch et al., 2017; Antonín et al., 2021). Recently, genome-level phylogenetic analyses have been used to provide high-resolution discrimination among Armillaria spp. (Kedves et al., 2021), but such analyses are restricted to species with sequenced genomes.
Kim, Mee-Sook; Heinzelmann, Renate; Labbe, Frederic; Ota, Yuko; Elías-Roman, Ruben Damian; Pildain, María Belen; Stewart, Jane E.; Woodward, Stephen; Klopfenstein, Ned B.2022. Armillaria root diseases of diverse trees in wide-spread global regions [Chapter 20]. Forest Microbiology. 2: 361-378.