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.]
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.
Not assessed. The species is poorly known and is likely to be under-recorded.
Fungal infections apparently lichenicolous on Xanthoria parietina and conforming broadly to the type description are currently named as C. licheniphilum in Britain.
Other members of Cladosporium s. lat. have a similar anatomy, and field characters and morphology alone cannot be used to identify them.
In GB&I, known from the thallus and especially the apothecia of Xanthoria parietina.
Found at four English sites (as of April 2016), in Bedfordshire, Buckinghamshire, Hertfordshire and Northamptonshire.