Morpho-molecular analyses and scanning electron microscopy reveal two new species of genus Lactarius from the northwestern Himalaya, India.

One of the largest subgenera of the genus Lactarius, Lactarius subg. Russularia is abundant in the forests of the Himalayas. This article proposes Lactarius crassostipes sp. nov. and Lactarius flavocorpus sp. nov. under the L. subgenus Russularia. It includes comprehensive macro- and micro-morphological descriptions, scanning electron microscopy (SEM) micrographs, drawings, and comparisons with related species. The taxa's novelty is validated using phylogenetic analyses based on nrITS. RESEARCH HIGHLIGHTS: SEM and subsequent nrITS-based molecular phylogeny revealed two novel species (L. crassostipes and L. flavocorpus) of the genus Lactarius subg. Russularia. To further characterize the size, form, and ornamentation of these novel species' basidiospores, SEM analysis is an additional tool. In L. crassostipes "crasso" means thick and "stipes" indicates stipe. In contrast to L. flavocorpus, where "flavocorpus" refers to the golden yellow fruiting body, the name alludes to its unique thick stipe. L. crassostipes sp. nov. and L. flavocorpus sp. nov have been collected from the coniferous and broad-leaved forests of Union Territory of Jammu and Kashmir, India, respectively. The diagnostic characteristics, habit, habitat, and similarities to related species are given.