Gyalectidium fuscum
Gyalectidium fuscum is a species of lichen-forming fungus in the family Gomphillaceae. It is a leaf-dwelling lichen known from tropical montane regions, including Papua New Guinea, tropical Africa, and northeastern Brazil. The species is distinguished by its distinctive brown-pigmented fruiting bodies, which are initially covered by a thin brown layer and later retain a reddish-brown zone at maturity, separating it from the closely related Gyalectidium filicinum.
Taxonomy
Gyalectidium fuscum was described as a new species in 2001 by Robert Lücking and Emmanuël Sérusiaux. In the original account it was treated as closely related to Gyalectidium filicinum but distinguished by the pigmentation of its apothecia, which are covered by a brown layer when young and later retain a brown to reddish-brown zone at maturity.Description
The thallus forms rounded patches on leaf surfaces, and are either single or clustered and about 1–2 mm in diameter. It is finely and greenish to greyish in colour.are rare and occur on the thallus surface. Their scales are well developed and obliquely oriented,, and typically bear two acute lateral projections. The scales are about 0.3–0.5 mm long and 0.2–0.4 mm broad, and are whitish to pale greenish grey. Apothecia are rounded, typically 1–4 per thallus patch, and about 0.2–0.3 mm in diameter. The is initially covered by a thin brown layer; in mature apothecia this becomes reduced to a narrow reddish-brown zone. A distinctly raised brown margin surrounds the disc, occasionally developing small whitish where crystals have accumulated beneath the surface. Ascospores are ellipsoid, 35–45 × 14–20 μm. Pycnidia have not been reported.