Key to the recognized species of Macrolepiota from China 1 Basidiomata with a volva at the base of the stipe M. velosa   1* Basidiomata without a volva at the base of the stipe 2 Pileus surface with brown

plate-like squamules; annulus complex; clamp connections common at the base of the basidia 3 Stipe surface with conspicuous fine brown squamules on whitish background; pileus squamules made up of yellowish-brown walled long hyphal segments, mainly 25–90 × 7–11 (14) μm M. procera   3* Stipe surface with fine brown squamules on whitish background; pileus squamules made up of yellowish-brown walled short hyphal segments, mainly 15–25 × 7–11 μm M. detersa     2* Pileus surface with pale ochraceous to brown fine squamules; annulus simple, or only slightly thicker near Lapatinib cell line the edge; clamp connections absent or present 4 Stipe surface with brown squamules; usually without clamps at the base of basidia M. mastoidea   4* Stipe surface smooth; usually with clamps at the base of basidia

5 Stipe base sometimes becomes orange when cut, pileus squamules composed of more frequently branched hyphae, cheilocystidia mainly clavate to broadly clavate M. dolichaula   5* Stipe base not changing color when cut, pileus squamules composed of seldom branched hyphae, cheilocystidia mainly obtusely fusiform to clavate M. orientiexcoriata         Discussion New species within Macrolepiota and species diversity in China As shown in Fig. 1, M. detersa is phylogenetically closely related to, but distinct from M. dolichaula and M. procera Gefitinib concentration based on the ITS data. Similarly,

M. orientiexcoriata is phylogenetically closely related to M. excoriata, M. mastoidea, and M. phaeodisca, but forms a clade of its own. As both M. detersa and M. orientiexcoriata have discrete characters to tell them apart from the currently described species, we described them as new species in this paper. In addition, the result that M. detersa clustered with 3 collections of M. sp. from Japan, which as a whole gets strong statistical supports, 100% of bootstrap and 1.00 bayesian PP support respectively, indicates that the three Urease Japanese collections are M. detersa (Fig. 1). By far, Europe is the species richest region of Macrolepiota, with 11 species in the current sense recorded (Candusso and Lanzoni 1990; Vellinga 2001; but numbers depend on species concepts), then followed by Asia with 9 species recorded (Manjula 1983; Pegler 1986; Shao and Xiang 1981; Teng 1996; Vellinga and Yang 2003), and 4 species in east Africa (Pegler 1977), and 3 species in Australia (Grgurinovic 1997; Vellinga 2003). Based on our present results, at least 6 morphological species were found in China, with representatives belonging to three different phylogenetic clades recovered by the analyses of the ITS data set.