Ceriporia species are resupinate, annual polypores and white-rot saprotrophs. Typically brightly colored, there are about 80 species distributed worldwide (Chen et al. 2020). Ceriporia spissa can be identified by its North American distribution, colorful orangish basidiocarp (ranging from yellow to red), tightly glued together hyphae that make squashing the tissue under a cover slip challenging, and basidiospore size. Ceriporia spissa is morphologically simiar to Ceriporia mellita and Ceriporia triumphalis, but the latter two species occur exclusively in Europe (Spirin et al. 2016).  

A fair number of crusts or crust-like species share the orangish coloration of Ceriporia spissa and are commonly misidentified as such on iNaturalist but can be easily distinguished by their lack of pores. Phanerochaete chrysorhiza produces extensive rhizomorphs and has an odontioid to hydnoid hymenophore. Phlebia coccineofulva is typically a brighter red color when fresh and has a merulioid to grandinoid hymenophore. Stereum complicatum is an orange effused-reflexed parchment fungus. Pyronema omphalodes is a bright orange crustose ascomycete that grows on recently burned ground. Another potential lookalike is not a single species at all but rather a consortium of microbes. In the spring, sap gets flowing and can ooze out of cuts in tree trunks or the stumps of recently felled trees, upon which a slimy orange mass may form. This slime is composed of yeasts, filamentous fungi, and bacteria that are said to feed on the sugary sap. The orange color is primarily a result of carotene production by the yeast Cryptococcus macerans.

Details