The Australasian species of Lactarius subgenus Gerardii (Russulales)

This paper provides an overview and identification key of the Australasian species of Lactarius subg. Gerardii. A molecular phylogeny based on the nuc DNA markers ITS, LSU and rpb2, combined with detailed morphological observations resulted in the delimitation of 12 strongly supported and morphologically recognizable species. Five new agaricoid species are described here: Lactarius hora, L. coniculus, L. limbatus, L. leae and L. leonardii. Other agaricoid species belonging to subg. Gerardii are L. atrovelutinus, L. bicolor, L. ochrogalactus and L. reticulatovenosus. Lactarius venosus is also considered as a member but could not be included in the molecular analysis. Two new pleurotoid species are discovered: L. genevievae and L. conchatulus, both close relatives of L. uyedae, but each with distinct characters. Their position within subg. Gerardii is supported in the phylogeny and by their microscopic characters. This study also confirms the existence of multiple cryptic species and species complexes for which species recognition or species delimitation remains problematic as is the case for the Australian species L. wirrabara. In general, detailed macroscopic and microscopic observations are needed to identify species of L. subg. Gerardii.