Patterns of basidiocarp growth in oak mazegill (Daedalea quercina, Polyporales) revealed by experimental and natural perturbations

In Polyporales, the pore field immediately behind the basidiocarp margin may configure the hymenophore. Basidiocarp growth is not restricted to the margin, however. Here, the importance of the pore field was assessed from two years’ of observations on naturally occurring oak mazegill (Daedalea quercina, Polyporales) basidiocarps and tested by experimental perturbations in natural habitats. Oak mazegill was chosen because the formed hymenophore has a unique and stable combination of poroid and lamellate features. Whether the pore field is required for basidiocarp growth was tested in 10 basidiocarps in which one side was resected. New growth was observed in six basidiocarps, and it occurred equally from the cut hymenophore and the intact pore field. New formation of hymenophore and pileus even occurred in seven out of 10 basidiocarps that had the entire pore field resected. Whether the hymenophore is configured permanently was tested on 54 basidiocarps on 10 trunks that were turned upside down. A new hymenophore grew through the old pileus, often far from the pore field, and its hymenophore configuration was invariably poroid despite the old hymenophore had lamellate features. In 48 experimentally banded basidiocarps, new hymenophore grew in the insertion hole of the band despite this being far from the pore field. The banded basidiocarps grew at an average rate of 5 mm per year. In conclusion, the capacity to configure the hymenophore is not confined to the pore field and it could be broadly present in the basidiocarp, possibly due to ubiquitous hyphal totipotency.