A New Species of Coprinellus (Psathyrellaceae, Agaricales) From Buner District, Pakistan

A new species, Coprinellus nigrolamellatus , is described hereby from the Buner District, Khyber Pakhtunkhwa Province, Pakistan. The species is distinguished based on both morphological features and molecular data, with nrITS sequences confirming its unique status. Coprinellus nigrolamellatus is characterized by small‐ to medium‐sized basidiomata; an applanate and grayish‐brown pileus with yellowish orange central disk; adnexed, slowly deliquescent, and black lamellae; mitriform basidiospores (in front view) distinctly flattened (in side view) with a central germ pore; clavate to broadly clavate cheilocystidia; irregularly cylindrical pileocystidia; thick‐walled and globose to subcylindrical veil elements; and the absence of pleurocystidia. Phylogenetically, it forms a well‐supported sister clade to Coprinellus verrucispermus within section Coprinellus . Descriptions, illustrations, phylogenetic analysis results, and comparisons with closely related taxa are provided for the studied species.