About Bjerkandera fumosa (Pers.) P.Karst.
The fruit bodies of Bjerkandera fumosa are either effused-reflexed โ meaning they spread over the substrate and curl back at the margin to form a cap โ or fully cap-shaped, and attach directly to their substrate without a stem. The caps can grow alone, in closely overlapping clusters, and often fuse with adjacent caps. Caps typically measure 5โ10 cm (2.0โ3.9 in) across and up to 2 cm (0.8 in) thick; their upper surface is buff-coloured, with a texture ranging from finely hairy (tomentose) to smooth. The pores on the underside of the cap are circular to angular, with 2 to 5 pores per millimetre. Bjerkandera fumosa has a monomitic hyphal system, meaning it contains only generative hyphae. Its basidia are club-shaped, and measure 20โ22 ฮผm. Its spores are short cylindrical in shape, measuring 5.5โ7 by 2.5โ3.5 ฮผm. The spores are smooth, hyaline, and show no reaction when tested with Melzer's reagent. Bjerkandera fumosa causes white rot in various hardwood tree species. It has a circumboreal distribution across the Northern Hemisphere.
