New species and new records of Laccaria (Agaricales, Basidiomycota) from Northern Thailand.

Two new species Laccariapseudoalba and L.subroseoalbescens are described and illustrated, based on morphological characteristics and molecular phylogenetic analysis. Two new records, Laccariaumbilicata and L.yunnanensis from Thailand, are also reported. Laccariasubroseoalbescens is characterized by small basidiomata, stipe equal with an enlarged base, and nearly subclavate, pale pink to light orange. Laccariapseudoalba is characterized by pale orange to orange white pileus, has umbo when young on the pileus, and fistulose stipe of the pale to pastel red color. Phylogenetic analysis based on sequence data from rDNA internal transcribed spacer ITS1-5.8S-ITS2 rDNA (ITS), nuc 28S rDNA (28S), RNA polymerase II subunit 2 (rpb2), and translation elongation factor 1-α (tef1-α) are provided as further evidence. Molecular analysis confirms the phylogenetic positions of the two new species and two new records. The differences in characteristics of these two new species and closely related species are discussed herein.