Xylaria cubensis represents a complex of several species, each with potentially different host and substrate preferences.
Fruiting Body: 2–8 cm tall; 0.5–1.5 cm across; shaped more or less like a club, with a rounded tip; surface coppery brown, becoming blackish with maturity; becoming minutely pimpled and shallowly wrinkled with maturity, but not developing deep fissures and cracks; pseudostem short or almost non existent.
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The species make up several ecosystems, which are under threat. I suggest including it in the list of least concern (LC).

According to GBIF there are 687 occurrences in the world.

According to GBIF the countries with the most occurrences are United States and Brazil.

Ascomata of Xylaria cubensis are commonly encountered on decomposing angiosperm wood in
tropical, subtropical, and temperate forests across the globe, degrading both lignin and cellulose
thereby causing a physiological white rot (Rogers, 1984). However, closely related isolates are
frequently cultured in endophyte surveys, especially of tropical angiosperms, ferns, and
lycophytes (e.g., Fan et al., 2014; Fröhlich et al, 2000)

In Brazil the species was registered in an environmental protection area, but it is an area that suffers from anthropogenic actions.

Species found in environmental conservation area in Brazil. But like other species it needs preservation together with the beings with which it is associated.

The genus Xylaria presents many complexes that are not well defined, taxonomic and phylogenetic studies are needed to better define their species.

Isolates of X. cubensis are reported to have high morphological, genetic, and chemical diversity.