Lasiobotrys lonicerae
Anamorph: not known, but related species have been reported to produce a hyphomycetous anamorph in culture.
Teleomorph: colonies 2-5 mm diam., inhabiting living leaves, initially biotrophic but subsequently forming conspicuous black leaf spots, developing from a plate-like subcuticular hypostroma and breaking through the cuticle to form clusters of sclerotium-like sterile stromata from which ascostromata form, apparently dispersing as compound units. Stromata 200-350 µm diam. and 70-150 µm thick, discoid to pulvinate, matt black, formed of an outer layer of strongly melanized very thick-walled globose cells and an inner part of thinner-walled refractive cells that are glassy in appearance; attached to the hypostroma with a column of dark non-agglutinated thick-walled hyphae 2-3 µm diam. and surrounded by a well-developed fringe of similar hyphae that grow outwards and downwards, with the column below eventually fracturing to form a compound dispersal unit. Ascostromata 60-85 µm diam., ± globose, formed in a ring below the periphery of the stroma and connected by short thick-walled hyphae. composed of a single layer of very dark thick-walled angular to globose cells 4-6 µm diam., the ostiole minute and hardly papillate. Interascal tissue absent, at least at maturity. Asci formed in a 30-40 x 12-15 µm, clavate to cylindric-clavate, ± sessile, thick-walled and fissitunicate with an inconspicuous ocular chamber, not blueing in iodine, 8-spored. Ascospores arranged biseriately, 8.5-11.5 x 2.5-3.5 µm, cylindrical to cylindric-clavate, the apex obtuse and the base rounded, fairly thick-walled, golden brown, smooth, with a single septum near the apex, without a gelatinous sheath or appendages.
Not formally assessed. Only reported about ten times from GB&I and perhaps under-recorded, but the species is quite conspicuous. Targeted searches in northern Scotland have been successful.
The species is unmistakeable, with its clusters of black stromata on living leaves. It is unlikely to be confused with any other species on Lonicera in GB&I, though there are several other extralimital taxa associated with other species of Lonicera.
On living leaves of Lonicera periclymenum.
Most modern records are from northern Scotland, though the species has been reported recently from Yorkshire and Wickow (ROI) and there are historic records from Cornwall and Northamptonshire.