Monotropastrum kirishimense Suetsugu

This species has been collected several times, but was often treated as the color variant of Monotropastrum humile coined as M. globosum f. roseum in Honda, M. (1957: Scientific names of plants of Japan. Kousei-sya, Tokyo (in Japanese, not seen, cited after Imamura & Kurogi 2003)), later transferred to M. humile f. roseum by Yonekura (2011). However, using morphological, phenological, phylogenetic and mycorrhizal characteristics Suetsugu et al. (2022) discerned M. kirishimensis from M. humile not only by the rose colored petals, but also by more sepals (5-9 vs. 2-3) always appressed to the petals (vs. spreading at peak anthesis), extremely dense root-soil agglomerations (vs. strikingly less dense), the flowering time being more than a month later than M. humile, and finally by differing Russula spp. as fungal associates, even when both species grow at the same site. Moreover, molecular phylogeny revealed a distinct sister relationship between M. kirishimense and the M. humile complex. The type material originates from Kirishima/Kagoshima Prefecture, however, it also occours in other parts of Kyushu (the southernmost main island of Japan) and on the largest Japanese island Honshu (Suetsugu et al. 2022).