Lactarius | |
---|---|
Lactarius vietus | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Fungi |
Division: | Basidiomycota |
Class: | Agaricomycetes |
Order: | Russulales |
Family: | Russulaceae |
Genus: | Lactarius Pers. (1797) |
Diversity [1] | |
c. 583 species | |
Synonyms [2] | |
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 the closely related genus Russula , their flesh has a distinctive brittle consistency. It is a large genus with over 500 known species, [1] mainly distributed in the Northern hemisphere. Recently, the genus Lactifluus has been separated from Lactarius based on molecular phylogenetic evidence.
The genus Lactarius was described by Christian Hendrik Persoon in 1797 [3] with L. piperatus as the original type species. In 2011, L. torminosus was accepted as the new type of the genus after the splitting-off of Lactifluus as separate genus. [4] [5] [6]
The name "Lactarius" is derived from the Latin lac , "milk".
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Phylogenetic relationships of Lactarius, Lactifluus, Multifurca, and Russula according to Buyck et al. 2008. [7] |
Molecular phylogenetics uncovered that, while macromorphologically well-defined, milk-caps were in fact a paraphyletic genus; as a consequence, the genera Lactifluus was split from Lactarius, and the species L. furcatus was moved to the new genus Multifurca , together with some former Russula species. [4] [7] Multifurca also represents the likely sister group of Lactarius (see phylogeny, right). In the course of these taxonomical rearrangements, the name Lactarius was conserved for the genus with the new type species Lactarius torminosus ; this way, the name Lactarius could be retained for the bigger genus with many well-known temperate species, while the name Lactifluus has to be applied only to a smaller number of species, containing mainly tropical, but also some temperate milk-caps such as Lactifluus volemus and Lf. vellereus . [4] [5] [6]
Phylogenetic analyses have also revealed that Lactarius, in the strict sense, contains some species with closed (angiocarpous) fruitbodies, e.g. L. angiocarpus described from Zambia. [8] The angiocarpous genera Arcangeliella and Zelleromyces are phylogenetically part of Lactarius. [8] [9]
Systematics within the genus Lactarius is a subject of ongoing research. Three subgenera are currently accepted and supported by molecular phylogenetics: [10]
Some additional species, all tropical, do not seem to fall into these subgenera and occupy more basal positions within Lactarius. [9] This includes for example L. chromospermus from tropical Africa with an odd brown spore color. [9] [11]
Currently, over 600 species of the genus Lactarius are recognised, [12] while the angiocarpous genera Arcangeliella and Zelleromyces have not yet been synonymized with Lactarius. It is estimated that a significant number of Lactarius species remain to be described. [10]
The eponymous "milk" and the brittle consistency of the flesh are the most prominent field characters of milk-cap fruitbodies. The milk or latex emerging from bruised flesh is often white or cream, but more vividly coloured in some species; it can change upon exposition or remain unchanged. Fruitbodies are small to very large, gilled, rather fleshy, without veil, often depressed or even funnel-shaped with decurrent gills. Cap surface can be glabrous, velvety or pilose, dry, sticky or viscose and is often zonate. Several species have pits (scrobicules) on the cap or pileus surface. Dull colors prevail, but some more colorful species exist, e.g. the blue Lactarius indigo or the orange species of section Deliciosi . Spore print color is white to ocher or, in some cases, pinkish. Some species have angiocarpous, i.e., closed fruitbodies. [8]
Microscopically, Lactarius species have elliptical, rarely globoid spores with amyloid ornamentation in the form of more or less prominent warts or spines, connected by ridges, like other members of the family Russulaceae. The trama (flesh) contains spherical cells that cause the brittle structure. Unlike Russula, Lactarius also have lactiferous, i.e. latex-carrying hyphae in their trama.
Distinguishing Lactarius from Lactifluus based on morphology alone is difficult; there are no synapomorphic characters known so far that define both genera unequivocally but tendencies exist: [10] zonate and viscose to glutinose caps are only found in Lactarius, as well as closed (angiocarpous) and sequestrate fruitbodies. All known annulate and pleurotoid (i.e., laterally stiped) milk-caps, on the contrary, belong to Lactifluus.
Characters important for identification of milk-caps (Lactarius and Lactifluus) are: [13] [14] [15] initial colour of the latex and color change, texture of cap surface, taste (mild, peppery, or bitter) of latex and flesh, odor, and microscopical features of the spores and the cap cuticle (pileipellis). The habitat and especially the type of host tree can also be critical. While there are some easily recognizable species, other species can be quite hard to determine without microscopical examination. [15]
Lactarius is one of the most prominent genera of mushroom-forming fungi in the Northern hemisphere. It also occurs natively in Northern Africa, [13] tropical Africa, [16] tropical Asia, [9] [17] Central America, [18] and Australia. [19] Its possible native distribution in South America and different parts of Australasia is unclear, as many species in those regions, poorly known, might in fact belong to Lactifluus, which has a more tropical distribution than Lactarius. [20] Several species have also been introduced with their host trees outside their native range, [21] e.g. in South America, [22] Southern Africa, [16] Australia, [23] and New Zealand. [24]
Lactarius belongs to a lineage of ectomycorrhiza obligate symbionts. [25] As such, they are dependent on the occurrence of possible host plants. Confirmed habitats apart from temperate forests include arctic tundra and boreal forest, [26] mediterranean maquis, [13] [27] [28] tropical African shrubland, [16] tropical Asian rainforest, [9] [17] mesoamerican tropical oak forests, [18] and Australian Eucalyptus forests. [19]
While most species display a preference towards either broadleaf or coniferous hosts, [13] [14] some are more strictly associated with certain genera or species of plant hosts. A well-studied example is that of alders, which have several specialized Lactarius symbionts (e.g. L. alpinus , L. brunneohepaticus , L. lilacinus ), some of which even evolved specificity to one of the Alnus subgenera. [29] Other examples of specialized associations of Lactarius are with Cistus shrubs ( L. cistophilus and L. tesquorum ), [27] [28] beech (e.g. L. blennius ), birches (e.g. L. pubescens ), hazel (e.g. L. pyrogalus ), oak (e.g. L. quietus ), pines (e.g. L. deliciosus ), or fir (e.g. L. deterrimus ). For most tropical species, host plant range is poorly known, but species in tropical Africa seem to be rather generalist. [16]
Lactarius species are considered late-stage colonizers, that means, they are generally not present in early-colonizing vegetation, but establish in later phases of succession. [30] However, species symbiotic with early colonizing trees, such as L. pubescens with birch, will rather occur in early stages. [31] Several species have preferences regarding soil pH and humidity, [13] [14] which will determine the habitats in which they occur.
Several Lactarius species are edible. L. deliciosus notably ranks among the most highly valued mushrooms in the Northern hemisphere, while opinions vary on the taste of other species, such as L. indigo or L. deterrimus . Several species are reported to be regularly collected for food in Russia, Tanzania and Hunan, China. [32] Some Lactarius are considered toxic, for example L. turpis , which contains a mutagenic compound, [33] or L. helvus . There are, however, no deadly poisonous mushrooms in the genus. Bitter or peppery species, for example L. torminosus , are generally not considered edible, at least raw, but are nevertheless consumed in some regions, e.g. in Finland. [34] Some small, fragrant species, such as the "candy caps", are sometimes used as flavoring.
L. deliciosus is one of the few ectomycorrhizal mushrooms that has been successfully cultivated. [35] [36]
Different bioactive compounds have been isolated from Lactarius species, such as sesquiterpenoids, [37] aromatic volatiles, [38] [39] and mutagenic substances. [33] Pigments have been isolated from colored Lactarius species, such as L. deliciosus [40] or L. indigo . [41]
An extract of Lactarius badiosanguineus exhibits inhibitory activity on thrombin. [42]
The Russulaceae are a diverse family of fungi in the order Russulales, with roughly 1,900 known species and a worldwide distribution. They comprise the brittlegills and the milk-caps, well-known mushroom-forming fungi that include some edible species. These gilled mushrooms are characterised by the brittle flesh of their fruitbodies.
Lactarius deterrimus, also known as false saffron milkcap or orange milkcap, is a species of fungus in the family Russulaceae. The fungus produces medium-sized fruit bodies (mushrooms) with orangish caps up to 12 centimetres wide that develop green spots in old age or if injured. Its orange-coloured latex stains maroon within 30 minutes. Lactarius deterrimus is a mycorrhizal fungus that associates with Norway spruce and bearberry. The species is distributed in Europe, but has also found in parts of Asia. A visually similar species in the United States and Mexico is not closely related to the European species. Fruit bodies appear between late June and November, usually in spruce forests. Although the fungus is edible—like all Lactarius mushrooms from the section Deliciosi—its taste is often bitter, and it is not highly valued. The fruit bodies are used as source of food for the larvae of several insect species. Lactarius deterrimus can be distinguished from similar Lactarius species by difference in the mycorrhizal host or latex colour.
Lactarius deliciosus, commonly known as the delicious milk cap, saffron milk cap and red pine mushroom, is one of the best known members of the large milk-cap genus Lactarius in the order Russulales. It is native to Europe, but has been accidentally introduced to other countries along with pine trees, with which the fungus is symbiotic.
Russula is a very large genus composed of around 750 worldwide species of ectomycorrhizal mushrooms. They are typically common, fairly large, and brightly colored – making them one of the most recognizable genera among mycologists and mushroom collectors. Their distinguishing characteristics include usually brightly coloured caps, a white to dark yellow spore print, brittle, attached gills, an absence of latex, and absence of partial veil or volva tissue on the stem. Microscopically, the genus is characterised by the amyloid ornamented spores and flesh (trama) composed of spherocysts. Members of the related genus Lactarius have similar characteristics but emit a milky latex when their gills are broken. The genus was described by Christian Hendrik Persoon in 1796.
Lactifluus vellereus, commonly known as the fleecy milk-cap, is a quite large fungus in the genus Lactifluus. It is one of the two most common milk-caps found with beech trees, with the other being Lactarius subdulcis.
Lactarius torminosus, commonly known as the woolly milkcap or the bearded milkcap, is a large species of agaric fungus. A common and widely distributed species, it is found in North Africa, northern Asia, Europe, and North America. It was first described scientifically by Jacob Christian Schäffer in 1774 as an Agaricus, and later transferred to the genus Lactarius in 1821 by Samuel Frederick Gray. A variety, L. torminosus var. nordmanensis, is known from the United States, Canada, and Switzerland. L. torminosus officially became the type species of Lactarius in 2011 after molecular studies prompted the taxonomic reshuffling of species between several Russulaceae genera.
Milk-cap is a common name that refers to mushroom-forming fungi of the genera Lactarius, Lactifluus, and Multifurca, all in the family Russulaceae. The common and eponymous feature of their fruitbodies is the latex ("milk") they exude when cut or bruised. Mushrooms with typical milk-cap characteristics are said to have a lactarioid habit. Some of them are edible.
Lactifluus piperatus, commonly known as the blancaccio, is a semi-edible basidiomycete fungus of the genus Lactifluus. Despite being edible, it is not recommended by some because of its poor taste, though can be used as seasoning when dried. The fruiting body is a creamy-white mushroom which is funnel-shaped when mature, with exceptionally crowded gills. It bleeds a whitish peppery-tasting milk when cut. Widely distributed across Europe and eastern North America, Lactifluus piperatus has been accidentally introduced to Australia. Mycorrhizal, it forms a symbiotic relationship with various species of deciduous tree, including beech, and hazel, and fruiting bodies are found on the forest floor in deciduous woodland.
Lactifluus volemus, formerly known as Lactarius volemus, and commonly known as the weeping milk cap or bradley, is a species of fungus in the family Russulaceae. It is widely distributed in the northern hemisphere, in temperate regions of Europe, North America and Asia as well as some subtropical and tropical regions of Central America and Asia. A mycorrhizal fungus, its fruit bodies grow on the ground at the base of various species of trees from summer to autumn, either individually or in groups. It is valued as an edible mushroom, and is sold in markets in Asia. Several other Lactifluus mushrooms resemble L. volemus, such as the closely related edible species L. corrugis, but these can be distinguished by differences in distribution, visible morphology, and microscopic characteristics. L. volemus produces a white spore print and has roughly spherical spores about 7–8 micrometres in diameter.
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 contains six species known from the United States, Mexico, Costa Rica, India, China, Thailand, Australia, and New Caledonia, but so far has not been reported from Europe, Africa, or South America. Four of those species were formerly classified as Russula section Ochricompactae, and Multifurca furcata was originally described as a Lactarius species.
Lactarius sanguifluus, commonly known as the bloody milk cap, is a species of fungus in the family Russulaceae. First described from France in 1811, the species was given its current name by Elias Fries in 1838 when he transferred it to Lactarius. Found in Asia, Mediterranean Africa, and Europe, fruit bodies (mushrooms) grow scattered or in groups on the ground under conifers, especially Douglas fir. When bruised or cut, the fruit bodies ooze a blood-red to purple latex that slowly turns greenish upon exposure to air. The caps are orangish to reddish-brown, and become funnel-shaped with age. The gills are pinkish to purplish. Different forms have been described from Italy, but these are not universally accepted as distinct. L. sanguifluus mushrooms are edible, and sold in rural markets of Europe and Asia. Fruit bodies grown in polluted soil, including roadsides subject to heavy traffic, can bioaccumulate toxic heavy metals. Several sterols and pigment have been isolated and identified from the mushrooms.
Zelleromyces is a genus of fungi in the family Russulaceae. It was first described by mycologists Rolf Singer and Alexander H. Smith in 1960 to contain hypogeous (underground) fungi with gasteroid fruit bodies that "bleed" latex when they are cut.
Lactarius pubescens, commonly known as the downy milk cap, is a species of fungus in the family Russulaceae. It is a medium to large agaric with a creamy-buff, hairy cap, whitish gills and short stout stem. The fungus has a cosmopolitan distribution, and grows solitarily or in scattered groups on sandy soil under or near birch.
Lactifluus deceptivus, commonly known as the deceiving milkcap, is a common species of fungus in the family Russulaceae. It is found throughout eastern North America on the ground in coniferous forests near hemlock or deciduous forests near oak, and in oak-dominated forests of Costa Rica. It produces large mushrooms with funnel-shaped caps reaching up to 25 cm (9.8 in) in diameter, on top of hard white stems that may reach 4–10 cm (1.6–3.9 in) long and up to 3 cm (1.2 in) thick. The gills are closely spaced together and yellowish-cream in color. When young, the cap is white in all parts, but the depressed center becomes dull brownish in age and breaks up into scales. The edge of the cap has a roll of cottony tissue that collapses as the cap expands. The surface of the stem—especially near the base—has a velvety texture. The mushroom "bleeds" a milky white acrid latex when it is cut or injured. Similar milk-cap species with which L. deceptivus might be confused include Lactifluus piperatus, L. pseudodeceptivus, L. caeruleitinctus, L. subvellereus, Lactarius arcuatus and Lactarius parvulus.
Lactifluus is one of three genera of mushroom-forming fungi containing species commonly named "milk-caps", the others being Lactarius and Multifurca. It has been separated from Lactarius based on molecular phylogenetic evidence but is very similar to that genus. There are roughly 150 known Lactifluus species, which have a mainly tropical distribution but are also found in the north temperate zone and Australasia. Some of them are edible mushrooms.
Lactifluus aureifolius is a species of agaric fungus in the family Russulaceae. It is found in Burundi, which grows in miombo woodland dominated by Brachystegia utilis. The fungus was described in 1996 as a species of Lactarius.
Russula campinensis is a neotropical species in the genus Russula. This species is highly different from most other known Russula species in that it has very small (2–17 mm), pleurotoid fruitbodies that develop on tree trunks in up to 2 m elevation from the forest floor. It was described as Lactarius campinensis from Brazil (Amazonas) by Rolf Singer. T.W. Henkel, M.C. Aime and S.L. Miller later found this species in tropical rainforest of the Pakaraima Mountains, Guyana, and showed with molecular phylogenetic methods that it belongs to Russula. Although forming fruitbodies on wood, R. campinensis is a root-symbiotic ectomycorrhizal species and has been observed in Guyana associated with Dicymbe altsonii and D. jenzenii trees in the legume subfamily Caesalpinioideae.
Lactifluus clarkeae, formerly known as Lactarius clarkeae, is a species of mushroom-forming fungus in the family Russulaceae. It is found in Australia and New Zealand in mycorrhizal association with species of Nothofagus and the family Myrtaceae.
To date, 583 Lactarius species have been recorded globally
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