Fuscidea arboricola
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| Fuscidea arboricola | |
|---|---|
Scientific classification  | |
| Kingdom: | Fungi |
| Division: | Ascomycota |
| Class: | Lecanoromycetes |
| Order: | Umbilicariales |
| Family: | Fuscideaceae |
| Genus: | Fuscidea |
| Species: | F. arboricola |
| Binomial name | |
| Fuscidea arboricola | |
Fuscidea arboricola is a species of crustose lichen-forming fungus in the family Fuscideaceae.[1] It was described in 1992 from material collected in Norway. The thallus forms small greyish to brownish patches on acidic bark, typically reproducing by pale green soredia (powdery vegetative propagules) rather than by ascospores. The species occurs in moist forests across Europe, Macaronesia, and eastern North America.
Fuscidea arboricola was described in 1992 by Brian Coppins and Tor Tønsberg from material collected in Nordland, Norway, where the type specimen was found on the trunk of Betula pubescens. Tønsberg placed the species in the Fuscidea cyathoides group because of its medially constricted spores and well-developed apothecial margin.[2] In his revision of North American species of Fuscidea, Alan Fryday accepted it as a distinct species and noted that several earlier eastern North American collections had been misidentified as Fuscidea lightfootii.[3]
Description
The thallus is crustose and usually broken into small greyish-, greenish-, or brownish areoles surrounded by a distinct brown prothallus, often giving the lichen an overall brownish appearance. It may form rosettes up to 3 (rarely up to 5) cm across, though neighbouring thalli can merge into larger irregular patches. The soralia are pale yellowish green to pale green, sometimes brown-tinged, and are usually discrete rather than forming a continuous powdery crust; the soredia are fine, mostly 20–30 micrometres (μm) in diameter.[2] Apothecia (fruiting bodies) are uncommon, but when present they are dark brown to brownish black, up to 0.8 mm wide, and often develop a flexuose margin.[2][3] The ascospores are simple or occasionally have a single septum (1-septate), usually with a distinct median constriction, and measure 7–9 × 4–5 μm.[2][3] Pycnidia are also uncommon; they are blackish brown and produce narrowly obovoid to somewhat rod-shaped (bacilliform) conidia measuring 3–3.5 × 1–1.5 μm.[2] Chemically, the species contains fumarprotocetraric acid, sometimes with traces of protocetraric acid and cph-2.[2] It is the only species of Fuscidea known to contain fumarprotocetraric acid.[3]