Colonial morphotypes of Posidoniomyces atricolor in vitro (type isolate BRK-21). a Compact morphotype with substrate mycelium b, d compact colonies with a cerebriform pattern c colony of P. atricolor on PCA e rhizoidal and compact (arrow) daughter colonies on PCA washed with sterile tap water f detail of the colonies encircled in e; g, h terminal capitate swellings on the surface of compact colonies i–k conspicuous swellings on aerial mycelium. Scale bars: 500 μm (a, d), 1000 μm (b, c), 5 mm (e), 200 μm (f), 100 μm (g), 20 μm (h).