The ectomycorrhizal genus Lactifluus is known to contain many species complexes, consisting of morphologically very similar species, which can be considered cryptic or pseudocryptic. In this paper, a thorough molecular study is performed of the clade around Lactifluus deceptivus (originally described by Peck from North America) or the deceptive milkcaps. Even though most collections were identified as L. deceptivus, the clade is shown to contain at least 15 species, distributed across Asia and America, indicating that the L. deceptivus clade represents a species complex. These species are morphologically very similar and are characterized by a tomentose pileus with thinwalled hyphae and a velvety stipe with thick-walled hyphae. An ITS1 sequence was obtained through Illumina sequencing for the lectotype of L. deceptivus, dating from 1885, revealing which clade represents the true L. deceptivus. In addition, it is shown that three other described species also belong to the L. deceptivus clade: L. arcuatus, L. caeruleitinctus and L. mordax, and molecularly confirmed that L. tomentoso-marginatus represents a synonym of L. deceptivus. Furthermore, two new Neotropical species are described: Lactifluus hallingii and L. domingensis.

The ectomycorrhizal milkcap genus Lactifluus is commonly found within Central and West African gallery forests. During field expeditions in Cameroon and Togo, several collections of white Lactifluus species were found, resembling Lactifluus foetens. Molecular and morphological research indicates that these collections belong to two unrelated species, i.e. Lactifluus foetens and an undescribed taxon. The latter is here described as Lactifluus albomembranaceus sp. nov. from the gallery forests in Central and Western Africa. In Cameroon, at least, Lactifluus albomembranaceus is a popular edible fungus that is harvested for personal consumption and offered for sale at local markets.