''Lactifluus'' is one of three genera of

mushroom A mushroom or toadstool is the fleshy, spore-bearing fruiting body of a fungus, typically produced above ground, on soil, or on its food source. ''Toadstool'' generally denotes one poisonous to humans. The standard for the name "mushroom" is ...

-forming fungi containing species commonly named " milk-caps", the others being ''

Lactarius ''Lactarius'' is a genus of mushroom-producing, ectomycorrhizal fungi, containing several edible species. The species of the genus, commonly known as milk-caps, are characterized by the milky fluid ("latex") they exude when cut or damaged. Like ...

'' and ''

Multifurca ''Multifurca'' is a rare genus of ectomycorrhizal fungi in the family Russulaceae. It was described in 2008, after molecular phylogenetic study had shown that it forms a monophyletic lineage within the family, sister to ''Lactarius''. The genus c ...

''. It has been separated from ''

'' based on

molecular phylogenetic Molecular phylogenetics () is the branch of phylogeny that analyzes genetic, hereditary molecular differences, predominantly in DNA sequences, to gain information on an organism's evolutionary relationships. From these analyses, it is possible to ...

evidence but is very similar to that genus. There are roughly 150 known ''Lactifluus'' species, which have a mainly

tropical The tropics are the regions of Earth surrounding the Equator. They are defined in latitude by the Tropic of Cancer in the Northern Hemisphere at N and the Tropic of Capricorn in the Southern Hemisphere at S. The tropics are also referred to ...

distribution but are also found in the north temperate zone and

Australasia Australasia is a region that comprises Australia, New Zealand and some neighbouring islands in the Pacific Ocean. The term is used in a number of different contexts, including geopolitically, physiogeographically, philologically, and ecologic ...

. Some of them are

edible mushroom Edible mushrooms are the fleshy and edible fruit bodies of several species of macrofungi (fungi which bear fruiting structures that are large enough to be seen with the naked eye). They can appear either below ground ( hypogeous) or above gro ...

Systematics and taxonomy

The genus ''Lactifluus'' was described in 1806 by French naturalist Henri François Anne de Roussel, with the type species '' Lactifluus piperatus''. Later, ''Lactifluus'' was largely considered a

synonym A synonym is a word, morpheme, or phrase that means exactly or nearly the same as another word, morpheme, or phrase in a given language. For example, in the English language, the words ''begin'', ''start'', ''commence'', and ''initiate'' are al ...

of ''Lactarius'', until

work showed in 2008 that ''

'' was not a

monophyletic In cladistics for a group of organisms, monophyly is the condition of being a clade—that is, a group of taxa composed only of a common ancestor (or more precisely an ancestral population) and all of its lineal descendants. Monophyletic gr ...

group. In the following, the name ''Lactarius'' was conserved for the biggest of the sub

clade A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. Rather than the English ter ...

s revealed, containing most well-known north temperate species. Thus, the name ''Lactifluus'' could be used for the smaller genus, necessitating only a few name changes, as combinations with ''Lactifluus'' had already been made previously for many temperate species. New combinations have since been proposed for several species formerly classified in ''Lactarius''. A phylogenetics-based revision in 2017 divided the genus in four

subgenera In biology, a subgenus (plural: subgenera) is a taxonomic rank directly below genus. In the International Code of Zoological Nomenclature, a subgeneric name can be used independently or included in a species name, in parentheses, placed between ...

: ''Lactifluus'', ''Lactariopsis'', ''Gymnocarpi'' and ''Pseudogymnocarpi''. They are further subdivided into

section Section, Sectioning or Sectioned may refer to: Arts, entertainment and media * Section (music), a complete, but not independent, musical idea * Section (typography), a subdivision, especially of a chapter, in books and documents ** Section sig ...

, but not all species are assigned to named sections. Many of these new groups do not correspond to previous subdivisions based mainly on morphology.

Selected species

Lactifluus_sp_G3264_pleurotoid_French_Guiana_cropped

, there are roughly 150 described species, classified in four subgenera. Some notable species are listed below under their respective subgenera. * Subgenus ''Lactifluus'' :* '' Lactifluus corrugis'' – 'corrugated-cap milky' (North America) :* '' Lactifluus piperatus'' – 'peppery milk-cap' (Europe and North America) :* '' Lactifluus volemus'' – 'weeping milk-cap' or 'voluminous-latex milky' (North and Central America, Europe, Asia) * Subgenus ''Lactariopsis'' :* '' Lactifluus aureifolius'' (tropical Africa) :* '' Lactifluus deceptivus'' – 'deceiving milk-cap' (North and Central America) :* '' Lactifluus densifolius'' (tropical Africa) :* '' Lactifluus edulis'' (tropical Africa) :* '' Lactifluus heimii'' (tropical Africa) :* '' Lactifluus vellereus'' – 'fleecy milk-cap' (Europe) * Subgenus ''Gymnocarpi'' :* '' Lactifluus clarkeae'' (Australia and New Zealand) * Subgenus ''Pseudogymnocarpi'' :* '' Lactifluus hygrophoroides'' (North America)

Description

''Lactifluus'' closely resembles its lookalike genus ''Lactarius'', with whom it shares the brittle flesh of the fruit bodies and the milk-like latex exuded when bruised. So far,

synapomorphic In phylogenetics, an apomorphy (or derived trait) is a novel character or character state that has evolved from its ancestral form (or plesiomorphy). A synapomorphy is an apomorphy shared by two or more taxa and is therefore hypothesized to have ...

characters for the genus have not been discovered, there are only tendencies that distinguish it from ''Lactarius''. Pleurotoid (laterally stiped) fruitbodies are only known in ''Lactifluus'', while species with closed (angiocarpous) fruitbodies only occur in ''Lactarius''. Microscopically, thick-walled elements in the

pileipellis The pileipellis is the uppermost layer of hyphae A hypha (; ) is a long, branching, filamentous structure of a fungus, oomycete, or actinobacterium. In most fungi, hyphae are the main mode of vegetative growth, and are collectively call ...

and stipitipellis (

cuticle A cuticle (), or cuticula, is any of a variety of tough but flexible, non-mineral outer coverings of an organism, or parts of an organism, that provide protection. Various types of "cuticle" are non- homologous, differing in their origin, structu ...

of the stipe) and sphaerocytes in the trama of the lamellae are common in ''Lactifluus'', but rare in ''Lactarius'' species.

Edibility

Several species in the genus are edible. '' Lactifluus volemus'' especially is a choice mushroom in the northern temperate region.

References

External links

* {{Taxonbar, from=Q15991147 Russulales genera