Morphology of Melanconiella betulicola from Betula albosinensis. A–B habit of pseudostromata on branches C transverse section through perithecia D longitudinal section through perithecia E–F habit of acervuli on branches G transverse section through acervulus H longitudinal section through acervulus I asci and ascospores J–K ascus and ascospores L–O ascospores P conidiophores, conidiogenous cells and conidia Q conidia. Scale bars: 2 mm (A, E), 500 μm (B–D, F–H), 10 μm (J–K, P–Q), 5 μm (L–O).