Fig. S1 & Tables S1-S4

Figure S1. Overview map of the biogeographical regions used for Table 1. Biogeographic regions are based on biogeographic realms (https://ecoregions2017.appspot.com/), with three major differences: Western Palearctic (Western part of the Palearctic realm), Asia (Eastern part of the Palearctic realm combined with the Indo-Malay realm), and Australasia (Australasian realm combined with the Oceanian realm). The Palearctic realm was spilt into Western Palearctic and Eastern Palearctic, Eastern Palearctic and the Indo-Malay realm form together the Asia region, and the Australasian realm is combined with the Oceania realm to form the Australasian region.Table S1. List of described Lactifluus species, together with the year of description, taxonomical classification (subgenus, section), the indication of how this taxonomical position was defined, the source(s) of this classification, and notes.Table S2. Extra information on the preliminary study of metabarcoding data of the genus Lactifluus, retrieved from the GlobalFungi website.Table S3. Overview of the results of the preliminary study of metabarcoding data of the genus Lactifluus, retrieved from the GlobalFungi website. Due to the generally shorter length and lower quality of environmental sequence data, the numbers in the table are to be considered an estimate.Table S4. List of the putative new species found in the environmental sequences. References of studies cited are given in S3.