Cladosporium licheniphilum  

Anamorph: Colonies confined to apothecia of the host lichen, caespitose, reddish brown, somewhat shiny. Mycelium immersed; hyphae branched, sinuous, 5–8 µm wide, hyphal cells around the conidiophores swollen. Conidiophores solitary or in small, loose tufts, arising from internal swollen hyphal cells, erect, straight to slightly curved, subcylindrical to slightly geniculate-sinuous, unbranched to usually 1–3 times branched, conidiophores (65–)90–190 × 5–8 µm, somewhat wider at the base and gradually narrowed towards the apex, 5–14-septate, usually not constricted at the septa, dark brown, paler towards the apex, thick-walled, but wall of the terminal conidiogenous cells thinner; conidiogenous cells integrated, terminal, (7–)9–20 µm long, subcylindrical-conic to slightly geniculate-sinous, proliferation sympodial, with a single or usually numerous, up to 12, coronate conidiogenous loci, 1–2 µm diam. Conidia catenate, usually in branched acropetal chains, subglobose, limoniform to ellipsoid-subcylindrical, 0–1-septate, aseptate conidia 3.5–8 × 3–5 µm, septate conidia 7–13 × 5–7 µm, usually not constricted at the septa, pale brown or yellowish brown, wall thin to slightly thickened, smooth. [Information extracted from Heuchert & Braun (2006), describing the type material growing on Pertusaria alpina.]
Teleomorph: unknown.

Uwe Braun has identified lichenicolous material from Luxemburg and Austria, growing on Xanthoria parietina, as C. licheniphilum. There is the possibility that specimens of Cladosporium apparently lichenicolous on X. parietina may actually be another species of this large and incompletely understood genus and may not be obligately lichenicolous. British material on X. parietina conforms broadly to the above description. It forms dark reddish brown ‘furry’ patches on the host, especially the apothecia. The conidiophores are often unbranched. Some specimens are found growing in close association with infections of Marchandiomyces aurantiacus but others appear to infect the host without the presence of other lichenicolous fungi.