(a) The phylogeny of representative fungal species with sequenced genomes. CM taxa are shown with grey background. Pe, Pezizomycotina. Ag, Agaricomycotina. Sa, Saccharomycotina. Ta, Taphrinomycotina. N. cra, Neurospora crassa. A. nid, Aspergillus nidulans. T. mel, Tuber melanosporum. S. cer, Saccharomyces cerevisiae. C. alb, Candida albicans. N. irr, Neolecta irregularis. S. com, Saitoella complicata. T. def, Taphrina deformans. S. pom, Schizosaccharomyces pombe. P. gra, Puccinia graminis. S. ros, Sporobolomyces roseus. U. may, Ustilago maydis. L. bic, Laccaria bicolor. C. cin, Coprinopsis cinerea. R. del, Rhizopus delemar. B. den, Batrachochytrium dendrobatidis. (b) A simplified representation of the hypha and pore-associated membranous organelles. The colours of these organelles correspond to the text colours of the group they represent. (c) A Neolecta fruiting body collected from Black Mountain, New Hampshire. Scale bar, 5 mm. (d) Septal pore associated organelles of N. irregularis. The left panel shows an electron dense structure, which is apparently not membrane-delimited. The middle panel shows a septum that has been plugged by a Woronin body-like organelle. The right panel shows a Woronin body-like organelle free in the cytoplasm. The arrows indicate the pore and arrowheads point to the lipid bilayer. Scale bar, 250 nm. This figure is complemented by Supplementary Fig. 1, which shows additional views of the Neolecta fruiting body.