Rhizomorph structures confirm the relationship between Lycoperdales and Agaricaceae (Hymenomycetes, Basidiomycota)

Rhizomorphs provide systematically important traits. Therefore, in the present study the rhizomorph features of some species of (a) the gastroid genera Bovista, Handkea, and Lycoperdon, (b) the agaricoid genera Agaricus, Leucoagaricus, Leucocoprinus, Lepiota, Macrolepiota, and (c) the secotioid genus Podaxis were studied to test the molecular biological hypothesis of a systematical relationship between these genera. All genera revealed an agaricoid type of rhizomorph with very long, almost non-septate, thick-walled, dextrinoid emanating hyphae. Only Agaricus bisporus differed in this respect. In this species, the very long emanating hyphae are not thick-walled or dextrinoid. These differences can either be ascribed to the different habitat of A. bisporus in comparison to A. abruptibulbus, or are perhaps a consequence of their affiliation to different sections within this genus. It is concluded that rhizomorph structures confirm the results of DNA-sequence analyses that have already pointed out a relationship between Agaricus, Handkea, Lycoperdon, and Macrolepiota.