Arrhenia peltigerina (Peck) Redhead, Lutzoni, Montcalvo & Vilgalis

 Lichenized basidiomycete fungus of Peltigera sp.

     Pileus 0,5-2 cm in diameter, more or less depressed in the center, surface slightly felt-like, hygrophane (changing colour according to hygrometry), slightly ribbed when moist, beige-ochre, ochre fading when drying. Lamellae well separated, decurrent, divided, pale ochre, margin darker. Stipe cylindrical, 1-1,5 x 0,2-0,3 cm, weakly pubescent, felted at the base, whitish to pale-ochre. Flesh with clamped hyphae. Spores issued from tetrasporic clamped basidia, non amyloid, largely ellipsoid and tear-shaped,  8-10 x 5-6,5 µm. Species growing from October to December grafted on Peltigera thalli on calcified and dry dunes, notably on Peltigera hymenina. May be confused with Gamundia striatula that displays a very similar aspect and shares the same habitat, but with cystidia.*