Crinipellis pedemontana, a new agaric growing on stems of dead grasses in an Italian urban park, is described and illustrated. It fits in sect. Grisentinae on account of the green reaction with KOH and ammonia and its bright colored pileus. The unique combination of purple-violaceous tinges in the pileus and the presence of chlamydospores in the pileipellis characterize this species as new. Its taxonomic position within Crinipellis and the related genus Moniliophthora is discussed.