Lactarius repraesentaneus

Last updated
Lactarius repraesentaneus
Lactarius repraesentaneus 73826.jpg
in Lapland, Sweden
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Fungi
Division: Basidiomycota
Class: Agaricomycetes
Order: Russulales
Family: Russulaceae
Genus: Lactarius
Species:
L. repraesentaneus
Binomial name
Lactarius repraesentaneus
Britzelm. (1885)
Synonyms [1]

L. scrobiculatus var. repraesentaneus(Britzelm.) Killerm. (1933)

Contents

Lactarius repraesentaneus
Information icon.svg
Gills icon.png Gills on hymenium
Depressed cap icon.svg Cap is depressed
Decurrent gills icon2.svg Hymenium is decurrent
Bare stipe icon.svg Stipe is bare
Transparent spore print icon.svg
Spore print is yellow
Mycorrhizal fungus.svgEcology is mycorrhizal
Mycomorphbox Poison.pngEdibility is poisonous

Lactarius repraesentaneus, commonly known as the northern bearded milkcap, the northern milkcap, or the purple-staining bearded milkcap, [2] is a species of fungus in the family Russulaceae. It has a northerly distribution, and is found in temperate regions of North America and Europe, associated with spruce trees. Distinguishing features of its fruit body include the large orange-yellow cap up to 18 cm (7.1 in) wide, cream to pale yellow gills, and a yellow coarsely-pitted stem that is up to 12 cm (4.7 in) long and 3 cm (1.2 in) thick. Cut fruit bodies ooze a white latex that will stain mushroom tissue lilac to purple. Several chemicals have been isolated and identified from the fruit bodies that can modify the growth of plants, and the mushroom also has antibiotic activity against Staphylococcus aureus . L. repraesentaneus is poisonous, and consumption causes stomach aches.

Taxonomy

Lactarius repraesentaneus was first described by German mycologist Max Britzelmayr in 1885, based on material collected from Bavaria. [3] The variety Lactarius scrobiculatus var. repraesentaneus, proposed by Killermann in 1933, [4] is considered a synonym. [5] Rolf Singer in 1942 defined the subspecies L. repraesentaneus ssp. speciosus to include fruit bodies with matted fibers ("felt") arranged in concentric rings on the cap (zonate), in comparison with the nominate subspecies, where in young specimens the felt was evenly distributed on the cap surface, only becoming zonate at the cap margins in maturity. [6]

According to the classification proposed by Lexemuel Ray Hesler and Alexander H. Smith in their 1979 monograph of North American Lactarius species, L. repraesentaneus belongs in the stirps Speciosus of the section Aspideini, of the subgenus Piperites of genus Lactarius . Other species in stirps Speciosus include L. dispersus , L. subtorminosus , and L. speciosus , all of which have a hairy cap edge. [7] Singer's 1986 classification of the Agaricales does not divide subsection Aspideini into stirpes, instead grouping Lactarius repraesentaneus with L. aspideus , L. uvidus , L. luridis , L. psammicola , and L. speciosus. [8]

The mushroom is commonly known as the "northern bearded milkcap", the "northern milkcap", or the "purple-staining milkcap". [9] The specific epithet repraesentaneus is Latin for "well-represented". [10]

Description

The gills, normally a cream to dull yellow color, will stain purple when bruised. Lactarius repraesentaneus 72459.jpg
The gills, normally a cream to dull yellow color, will stain purple when bruised.
Young specimens are conspicuously bearded on the cap margin. Lactarius representaneus 41559 edit.jpg
Young specimens are conspicuously bearded on the cap margin.

The cap of L. repraesentaneus is 6–18 cm (2.4–7.1 in) wide, convex to broadly funnel-shaped. The margin (the edge of the cap) is conspicuously bearded on young specimens. The cap surface is faintly zoned to azonate, with a thin layer of matted fibers, often becoming scurfy with age. It is dry to somewhat sticky, light yellow to orange-yellow, sometimes with rusty tints when older. The attachment of the gills to the stem is slightly decurrent—running slightly down the length of the stem. The gills are moderately broad, close to crowded, sometimes forked near the stem. Normally a cream to pale ochraceous color, they will stain dull lilac to purple when bruised. [9]

The stem is 5–12 cm (2.0–4.7 in) long, 1–3 cm (0.4–1.2 in) thick, nearly equal in width throughout or enlarged downward, hollow at maturity, sticky to dry, scrobiculate (coarsely pitted), pale yellow to orange-yellow, and stains dull lilac to purple. The flesh is firm, brittle, white, and will stain dull lilac to purple when cut. The odor is sometimes faintly fragrant or not distinctive, but when the mushroom is dry it smells intensely of soap. [11] Its taste is mild to slightly acrid or somewhat bitter, and the flavor has been compared to sweet flag ( Acorus calamus ). [11] The abundant amount of latex produced by the mushroom is white to cream, unchanging, staining all tissues dull lilac to purple. It tastes mild to slightly acrid or somewhat bitter. The spore print is yellowish. [9] The fruit bodies are considered poisonous and consumption will cause stomach aches, but the nature of the toxic agents has not been identified. [12]

A new form, Lactarius repraesentaneus f. immutabilis, was described from Le Sappey, in the Haute-Savoie department of southeastern France in 2011. It differs in the staining reaction of its injured flesh. [13]

The spores are 8–12 by 6.5–9  μm, broadly ellipsoid to ellipsoid, ornamented with warts and ridges that do not form a reticulum, prominences up to 0.8 μm high, hyaline, and amyloid. The cap cuticle is an ixocutis—with the hyphae embedded in a slimy or gelatinized layer. [9]

Similar species

Lactarius scrobiculatus Lactarius scrobiculatus.JPG
Lactarius scrobiculatus

Lactarius repraesentaneus is similar in appearance to Lactarius scrobiculatus , which has latex that turns yellow when exposed to air, a different smell, a stinging flesh and a different reaction of the milk to alkali: in L. scrobiculatus the milk turns reddish-orange while that of L. representaneus does not change color. Lactarius uvidus also has a violet reaction but it has a different color and is not hairy at the margin of the cap. L. flavidus has a yellowish cap but does not have a hairy margin.

Habitat and distribution

Like other Lactarius species, L. repraesentaneus is thought to form mycorrhizal relationships with trees. This is a mutually beneficial relationship where the hyphae of the fungus grow around the roots of trees, forming a sheath of tissue. This enables the fungus to receive moisture, protection and nutritive byproducts of the tree, and affords the tree greater access to soil nutrients. The fruit bodies of L. repraesentaneus are found scattered or in groups on the ground under spruce from August to September. The fungus is distributed in higher elevations in the northern USA and southern Canada where spruce is present. It has also been reported from Alaska, California, and the Rocky Mountains. The frequency of its appearance is described as occasional to fairly common. [9] In Europe, where it is fairly rare, it is found mainly underneath sallows ( Salix capraea ) in forests at the foot of mountains on non-calcareous soil. It has been collected in Czechoslovakia, [11] Sweden, [14] Switzerland, the French Alps and England; overall, it is widely distributed throughout the temperate zone of the northern hemisphere. [11] The fungus has also been collected under birch ( B. pubescens , B. nana , and B. glandulosa ) in Greenland. [15]

Bioactive compounds

Lactarius repraesentaneus was reported to have antibiotic activity against Staphylococcus aureus in 1947. The substance responsible for the antibacterial activity, determined to be heat-sensitive, was not identified. [16] A number of chemicals have been isolated and identified from L. repraesentaneus that can regulate the growth of plants. The chemicals, in a class called sesquiterpenoids are named repraesentin A, and two related sesquiterpenes, namely repraesentins B and C. These compounds were shown to promote the radicle elongation of lettuce seedlings by 136%, 118% and 184% at 67 ppm, respectively. [17] Other compounds reported in 2006 are repraesentins D, E, and F. Repraesentin E showed the strongest growth promotion activity, 164% at 3.6 μm, of the three compounds toward the radicle elongation of lettuce seedlings. [18]

See also

Related Research Articles

<i>Lactarius torminosus</i> Fungus in the family Russulaceae from North Africa, northern Asia, Europe, and North America

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.

<i>Lactarius rubrilacteus</i> Species of fungus

Lactarius rubrilacteus is a species of mushroom of the genus Lactarius. It is also known as the bleeding milkcap, as is at least one other member of the genus, Lactarius sanguifluus.

<i>Lactarius scrobiculatus</i> Species of fungus

Lactarius scrobiculatus, commonly known as the scrobiculate milk cap, is a basidiomycete fungus, belonging to the genus Lactarius, whose members are called "milk caps." Taxonomy places this species into subgenus Piperites, section Zonarii, subsection Scrobiculati. The distinctive fruiting bodies of this large fungus are locally common in forests throughout Europe and North America. It is regarded as inedible by some authors, but it is nevertheless eaten in parts of Europe.

<i>Lactifluus volemus</i> Species of edible fungus in the family Russulaceae widely distributed in the northern hemisphere

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.

<i>Lactarius indigo</i> Edible fungus in the family Russulaceae from eastern North America, East Asia, and Central America

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.

<i>Lactarius sanguifluus</i> Species of fungus

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.

<i>Lactarius subflammeus</i> Species of fungus

Lactarius subflammeus, commonly known as the orange milk cap, is a species of fungus in the family Russulaceae. It is found in western North America in the late summer and fall and is especially common in the Pacific Northwest, where it grows on the ground near conifers like pine and spruce. The brightly colored fruit bodies, which are slimy or sticky, have scarlet caps when young that soon fade to brilliant orange. The stem—typically longer than the width of the cap—is also bright orange but the gills are whitish. The mushroom secretes a whitish latex when it is cut or injured.

<i>Lactarius aspideus</i> Species of fungus

Lactarius aspideus, commonly known as the bright yellow milkcap, is a species of fungus in the family Russulaceae. Distinctive characteristics of the fruit body include the sticky, pale yellow cap, and the abundant latex that stains the mushroom tissue lilac. It is found in North America.

<i>Lactarius alnicola</i> Species of fungus

Lactarius alnicola, commonly known as the golden milkcap, is a species of fungus in the family Russulaceae. The fruit bodies produced by the fungus are characterized by a sticky, vanilla-colored cap up to 20 cm (7.9 in) wide with a mixture of yellow tones arranged in faint concentric bands. The stem is up to 5 cm (2.0 in) long and has yellow-brown spots. When it is cut or injured, the mushroom oozes a white latex, which has an intensely peppery taste. The acrid taste of the fruit bodies renders them unpalatable. The fungus is found in the western United States and Mexico, where it grows in mycorrhizal associations with various coniferous trees species, such as spruce, pine and fir, and deciduous species such as oak and alder. It has also been collected in India. Two varieties have been named: var. pitkinensis, known from Colorado, and var. pungens, from Michigan.

<i>Lactarius pubescens</i> Species of fungus

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.

<i>Lactarius affinis</i> Species of mushroom

Lactarius affinis, commonly known as the kindred milk cap, is a species of milk-cap mushroom in the family Russulaceae. It is found northeastern North America, where it fruits in the summer and fall, and is common in the Great Lakes region. Its fruit bodies have medium to large, slimy dull yellow or brownish caps. Although not considered poisonous, it is unpalatable because of its highly acrid taste.

<i>Lactarius fumosus</i> Species of fungus

Lactarius fumosus, commonly known as the smoky milkcap, is a species of fungus in the family Russulaceae.

<i>Lactarius fallax</i> Species of fungus

Lactarius fallax, commonly known as the velvety milk cap, is a species of fungus in the family Russulaceae. Found in both spruce and mixed conifer forests, it is a fairly common species in the Pacific Northwest region of North America, with a northerly range extending to Alaska. Its fruit bodies are medium-sized, with velvety, brown to blackish caps up to 3–9 cm (1.2–3.5 in) in diameter bearing a distinct pointed umbo. The caps are supported by velvety stems up to 6 cm (2.4 in) long and 1.5 cm (0.6 in) thick. The mushroom oozes a whitish latex when it is cut, and injured tissue eventually turns a dull reddish color. The eastern North American and European species Lactarius lignyotus is closely similar in appearance, but can be distinguished by its differing range.

<span class="mw-page-title-main">Lactifluus deceptivus</span> Species of fungus

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.

<i>Lactarius argillaceifolius</i> Species of fungus

Lactarius argillaceifolius is a species of fungus in the family Russulaceae. The mushrooms produced by the fungus have convex to flattened drab lilac-colored caps that are up to 18 cm (7.1 in) wide. The cream-colored gills are closely spaced together and extend slightly down the length of the stem, which is up to 9 cm (3.5 in) long by 3.5 cm (1.4 in) thick. The mushroom produces an off-white latex when injured that stains the mushroom tissue brownish.

<i>Lactarius rufulus</i> Species of fungus

Lactarius rufulus, also known as the rufous candy cap or the southern candy cap, is a species of fungus in the family Russulaceae. The fruit bodies have fleshy brownish-red caps up to 10 cm (3.9 in) wide, and closely spaced pinkish-yellow gills. The stem is up to 12 cm (4.7 in) long and 3 cm (1.2 in) thick and colored similarly to the cap. The species, known only from California, Arizona, and Mexico, grows on the ground in leaf litter near oak trees. The fruit bodies resembles those of L. rufus, but L. rufulus tends to grow in clusters at a common base, rather than solitarily or in groups. A distinguishing microscopic characteristic is the near absence of large, spherical cells called sphaerocysts that are otherwise common in Lactarius species. Lactarius rufulus mushrooms are edible, and have an odor resembling maple syrup. They have been used to flavor confections and desserts.

<i>Lactarius vinaceorufescens</i> Species of fungus

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.

<i>Lactarius fuliginosus</i> Species of fungus

Lactarius fuliginosus, commonly known as the sooty milkcap, is a species of fungus in the family Russulaceae. The medium-sized fruit bodies have velvety, grayish-brown caps and crowded gills. It is found in deciduous forests of Asia, Europe, and North America.

<i>Lactarius xanthogalactus</i> Species of fungus

Lactarius xanthogalactus, commonly known as the yellow-staining milkcap is a poisonous species of fungus in the family Russulaceae. The species is found on the west coast of the United States and grows in the ground in association with hardwood and conifer trees. There are several other Lactarius species that bear resemblance to L. xanthogalactus, but most can be distinguished by differences in staining reactions, macroscopic characteristics, or habitat.

References

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