Panaeolus oligotrophus : A new species from central Florida, with notes on Panaeolus pumilus and Crucispora rhombisperma

A new species of fungus, Panaeolus oligotrophus, was discovered in central Florida. It looks similar to Panaeolus cinctulus but grows in nutrient-poor sandy soil, a rare habitat for this genus. Its physical features and DNA were analyzed and compared with other Panaeolus species. The study also found that the type specimen of Panaeolus pumilus is actually the same species as P. cinctulus. Additionally, another species, Crucispora rhombisperma, was reclassified into the genus Panaeolus and renamed Panaeolus rhombispermus because of its unusual spore shape. The potential for psilocybin production in the new species was checked by sequencing its genome.

Study at a glance

Abstract

Panaeolus oligotrophus sp. nov., a species macromorphologically resembling Panaeolus cinctulus, was collected in central Florida. Its macro- and micromorphological features are described and compared with all other known Panaeolus species. Color photos of the fruiting bodies and micrographs of key microscopic features are provided, along with an updated phylogenetic analysis. A microscopic reexamination of the holotype of Panaeolus pumilus supports its synonymy with P. cinctulus. The potential for psilocybin production by P. oligotrophus was determined by the characterization of the psilocybin gene cluster through whole genome sequencing. Phylogenetic and morphological evidence also supports the placement of Crucispora rhombisperma within Panaeolus, for which the new combination Panaeolus rhombispermus is proposed. This paper makes two interesting additions to the genus Panaeolus: P. rhombispermus introduces the novelty of an extremely differentiated spore morphology, and Panaeolus oligotrophus provides a rare example of Panaeolus in the underexplored niche of oligonutritive sandy soil.