Milk-cap (also milk cap, milkcap, or milky) 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. [1] Mushrooms with typical milk-cap characteristics are said to have a lactarioid habit. Some of them are edible.
Historically, these species were all united in the genus Lactarius, but molecular phylogenetic analysis has shown that they belong in fact to three distinct clades: [2] [3] [4]
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 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, mainly distributed in the Northern hemisphere. Recently, the genus Lactifluus has been separated from Lactarius based on molecular phylogenetic evidence.
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.
Lactarius controversus, commonly known as the poplar milkcap, is a large funnel-capped fungus within the genus Lactarius, which are collectively known as 'milk caps'. They all exude milky drops (lactate) from the flesh and gills when damaged.
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.
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.
Lactarius indigo, commonly known as the indigo milk cap, indigo milky, the indigo lactarius, or the blue milk mushroom, is a species of agaric fungus in the family Russulaceae. It is a widely distributed species, growing naturally in eastern North America, East Asia, and Central America; it has also been reported in southern France. L. indigo grows on the ground in both deciduous and coniferous forests, where it forms mycorrhizal associations with a broad range of trees. The fruit body color ranges from dark blue in fresh specimens to pale blue-gray in older ones. The milk, or latex, that oozes when the mushroom tissue is cut or broken — a feature common to all members of the genus Lactarius — is also indigo blue, but slowly turns green upon exposure to air. The cap has a diameter of 5–15 cm (2–6 in), and the stem is 2–8 cm (0.8–3 in) tall and 1–2.5 cm (0.4–1.0 in) thick. It is an edible mushroom, and is sold in rural markets in China, Guatemala, and Mexico. In Honduras, the mushroom is called a chora, and is generally eaten with egg; generally as a side dish for a bigger meal.
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.
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.
Lactarius vinaceorufescens, commonly known as the yellow-staining milkcap or the yellow-latex milky, is a poisonous species of fungus in the family Russulaceae. It produces mushrooms with pinkish-cinnamon caps up to 12 cm (4.7 in) wide held by pinkish-white stems up to 7 cm (2.8 in) long. The closely spaced whitish to pinkish buff gills develop wine-red spots in age. When it is cut or injured, the mushroom oozes a white latex that rapidly turns bright sulfur-yellow. The species, common and widely distributed in North America, grows in the ground in association with conifer trees. There are several other Lactarius species that bear resemblance to L. vinaceorufescens, but most can be distinguished by differences in staining reactions, macroscopic characteristics, or habitat.
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.
Multifurca furcata is a rare mushroom-forming fungus in the genus Multifurca. It was originally described as a Lactarius species in 1918 and was moved to the new genus Multifurca in 2008. With the genus Lactarius it shares the exudation of milk-like latex; however, it is microscopically and molecularly distinct. It has been found very infrequently, with currently known localities in the United States, Mexico, Costa Rica, and China.
Arcangeliella crassa, commonly known as the gasteroid milk cap, is a North American secotioid fungus species in the family Russulaceae. Like other members of its genus, it should probably be transferred to the genus Lactarius. It was described from a collection made in Stanislaus National Forest, Northern California.
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.