Leucoagaricus decipiens and La. erythrophaeus, a new species pair in sect. Piloselli.

Leucoagaricus decipiens and La. erythrophaeus, are described as new from Sardinia, Italy, and California, USA, respectively. These sister species show distinct reddening when touched on all parts of the basidiocarps and darken on drying. Their collariate lamellae, broadly cylindrical to utriform cheilocystidia and trichodermal pileus covering distinguish them morphologically from other species in sect. Piloselli, while nrITS and EF1-alpha sequences distinguish them from each other. Leucoagaricus erythrophaeus has been known under the name Lepiota roseifolia, but the type collection of this species does not fit the interpretation.