Oxneria fallax, also known as the hooded sunburst lichen, is a small yellow-orange to red-orange foliose lichen that grows on bark or rarely on rock or bone.[1] It is found all over the world except very dry areas.[2] [3]
The non-fruiting body (thallus) grows in rosettes to 3 cm in diameter.[2] [3] The rosettes sometimes coalesce with each other.[3] The lobes may appear divided at the tips. It is sometimes tightly appressed to the substrate (adnate), and sometimes not.[2] [3] The fruiting bodies (apothecia) are lecanorine, meaning that they are disc-like with a ring or rim of tissue around the that is made of tissue similar to the thallus.[2] The tips of the lobes form hood shaped soralia that produce powdery greenish yellow soredia.[2] It prefers growing on elm or oak bark, but can also be found on rocks, bone, or other wood types.[2] In Norway, it has been recorded growing on the bark of various sun-exposed broadleaved trees, including Acer, Betula, Fagus, Fraxinus, Populus, Tilia, and Ulmus. Lichen spot tests on the surface are K+ (purple), C−, KC−, and P−.[2]