Abstract
Eleven species of Lepiota section Stenosporae, reported as new for Thailand, are fully described and illustrated. Five are compared with European and North American collections based on nrITS sequence data. Two species possess a cutis-like pileipellis (L. aureofulvella, L. sp. 2) and nine are characterized by a trichodermium (L. alopochroa, L. castanea, L. citrophylla, L. erythrosticta, L. griseovirens, L. infelix, L. papillata, L. poliochloodes, L. sp. 1). New to science are Lepiota aureofulvella (close to L. boudieri) and L. papillata, which is characterized by small basidiomata covered with gray-brown to olive brown squamules, an orange-white to brownish-orange context, spurred basidiospores with straight or outgrown base, clavate to cylindrical cheilocystidia, and a trichodermal pileus covering. A key to Lepiota sect. Stenosporae in northern Thailand is provided.