Integrative taxonomy reveals an unexpected diversity in <i>Geastrum</i> section <i>Geastrum</i> (<i>Geastrales</i>, <i>Basidiomycota</i>)

A revision of the classification of Geastrum sect. Geastrum is presented on the basis of an integrative taxonomic approach, which involves the study of morphological, molecular, ecological, and chorological data. Four DNA regions are analysed: the ITS and LSU nrDNA, rpb1, and atp6. Phylogenetic reconstructions include 95 ingroup samples and show five main clades, which are considered as five subsections, one of them proposed as new (G. subsect. Hungarica), and a total of 27 lineages recognizable at species level. Discriminant function analyses, ANOVAs and Tukey's HSD tests on more than 500 basidiomata reveal the utility of several quantitative morphological characters for species delimitation. As a result of the combination of the different sources of taxonomic information, a revised taxonomy is presented and seven new species, viz., G. austrominimum, G. benitoi, G. britannicum, G. kuharii, G. meridionale, G. papinuttii, and G. thanatophilum, are proposed.