Xylopsora canopeorum

Xylopsora canopeorum has a thallus that ranges from crust-like to scale-like in appearance, with individual scales (squamules) measuring up to 0.5 mm in diameter. These scales often evolve into a coral-like crust as the lichen ages, initially adhering flatly to the surface before standing upright in a manner that seeks the direction of gravity (geotropically imbricate). Sporadically, the lichen forms soralia, structures that release powdery reproductive propagules called soredia, appearing in patches and bearing a bluish hue. The surface of the thallus shows a color palette ranging from greyish-green to medium brown, with a matte finish. Its edges may be finely notched or cut and are the same color as the rest of the upper surface. The uppermost layer (cortex) of the thallus is relatively thin, reaching up to 15 micrometers (μm), though it typically lacks a well-defined structure. Reproductive structures (apothecia), which are common in this species, appear as flat, black discs without a powdery coating (epruinose), measuring up to 0.6 mm across. The edges of these discs remain distinct and may either be smooth or somewhat wavy. The supporting structure of the apothecia (exciple) consists of densely packed fungal filaments, darker on the outer rim and lighter towards the center, without crystal formations. …

Xylopsora canopeorum is exclusively found in the central coastal region of California, with confirmed specimens collected within Big Basin Redwoods State Park and Armstrong Redwoods State Natural Reserve. These locations, situated respectively 11 km (6.8 mi) and 18 km (11 mi) away from the Pacific Ocean, are notable for their ancient coast redwood forests, providing a unique ecosystem for this lichen species. The exploration of forest canopies remains limited, largely due to the challenges and specialized skills and equipment needed to access the treetops. Chaenotheca longispora is another lichen found from a similar location in a California State Park and reported as a new species in 2019. In terms of its ecological niche, X. canopeorum grows on the coarse and fibrous bark of large coast redwood trees, sometimes extending to charred areas of the bark. This lichen is predominantly found at elevations ranging from 5 to 75 m (16 to 246 ft) above the forest floor, growing on the venerable and robust bark surfaces of the redwoods' main trunks. The presence of Xylopsora canopeorum is often associated with a community of other lichen species, including Carbonicola anthracophila, Fulgidea oligospora, F. sierrae, Hertelidea botryosa, and Hypocenomyce scalaris, which share the surfaces offered by the ancient trees of these old-growth forests.