Colonies olivaceous to dark brown, effuse, loose to dense, caespitose, velvety. Mycelium external, superficial; hyphae branched, 3−12 μm diam., cells 5−10 μm long, often subglobose, angular to irregularly swollen by constrictions at the septa, swollen cells sometimes aggregated, pale olivaceous to olivaceous-brown, occasionally subhyaline, smooth.
Anamorph: Stromata effuse, composed of swollen hyphal cells 5−12 μm diam., dark olivaceous-brown or medium brown, smooth, walls thickened. Conidiophores 39−265 × 3−6(−8) μm, 6−9 μm wide at the base, solitary, arising from swollen hyphal cells, or in loose to dense fascicles arising from stromata, erect to decumbent, straight to curved, subcylindrical, slightly geniculate-sinuous, unbranched to branched, occasionally somewhat attenuated towards the apex (up to 3.5 μm), 4- to 12-septate, at the base septa often closely spaced, occasionally slightly constricted at the septa, pale to medium olivaceous, sometimes paler towards the tips, occasionally subhyaline, smooth or almost so, walls slightly thickened, thin-walled towards the apex, rarely proliferating. Conidiogenous cells 8−53 μm long, terminal or intercalary, cylindrical, polyblastic, proliferatng sympodially, with up to 4 scars, conidiogenous loci not or only slightly protuberant, only occasionally denticle-like or situated on small lateral shoulders, thickened and darkened-refractive, 1−2 (−3) μm diam., intercalary conidiogenous cells sometimes somewhat swollen. Ramoconidia occasionally formed, subcylindrical to ampulliform, 21−32 × 4.5−5.5 μm, 0- to 5-septate, usually not constricted at the septa, smooth or rarely irregularly minutely verruculose, walls thickened, the base convex without a distinct hilum, 2−3 μm diam., apex with up to 5 hila. Conidia usually in branched chains, (2−)6−28 × 2.5−7(−10) μm, straight, rarely curved, variable in shape and size, fusiform, obovoid, limoniform, narrowly to broadly ellipsoidal, 0- to 3-septate, without any constrictions, pale olivaceous, occasionally subhyaline, smooth, walls hardly thickened, the apex rounded with up to 4 hila, base truncate to convex, sometimes attenuated, hila slightly protuberant, denticle-like, thickened, darkened-refractive, (0.5−)1−2(−2.5) μm diam.
Teleomorph: not known.
Not formally assessed. Currently known only from a single British collection, but the species is very likely to be under-recorded. It would presumably be assessed as Data Deficient.
Similar to Cladosporium epimyces (also on fruit-bodies of macrofungi) but with rarely formed ramoconidia that are shorter when present than those of C. epimyces. C. lycoperdinum also has more compact, almost always superficial mycelium.
In GB&I, recorded from an old fruit-body of Laetiporus sulphureus, but not strongly host-specific; the species has been reported from diverse macrofungi including species of Gomphidius, Lactarius, Lepiota, Lycoperdon, Piptoporus, Scleroderma and Suillus.
In GB&I, recorded from VC40 Shropshire.