Lactarius alnicola
Encyclopedia
Lactarius alnicola, commonly known as the golden milkcap, is a species of fungus
Fungus
A fungus is a member of a large group of eukaryotic organisms that includes microorganisms such as yeasts and molds , as well as the more familiar mushrooms. These organisms are classified as a kingdom, Fungi, which is separate from plants, animals, and bacteria...

 in the Russulaceae
Russulaceae
The Russulaceae are a family of fungi in the order Russulales. According to a 2008 estimate, the family contains 1243 species. Its species typically have fruit bodies with friable, chalk-like stalks, that break with a distinct crack, somewhat like a carrot but with porous flesh...

 family. The fruit bodies
Basidiocarp
In fungi, a basidiocarp, basidiome or basidioma , is the sporocarp of a basidiomycete, the multicellular structure on which the spore-producing hymenium is borne. Basidiocarps are characteristic of the hymenomycetes; rusts and smuts do not produce such structures...

 produced by the fungus are characterized by a sticky, vanilla-colored cap
Pileus (mycology)
The pileus is the technical name for the cap, or cap-like part, of a basidiocarp or ascocarp that supports a spore-bearing surface, the hymenium. The hymenium may consist of lamellae, tubes, or teeth, on the underside of the pileus...

 up to 20 cm (7.9 in) wide with a mixture of yellow tones arranged in faint concentric bands. The stem
Stipe (mycology)
thumb|150px|right|Diagram of a [[basidiomycete]] stipe with an [[annulus |annulus]] and [[volva |volva]]In mycology a stipe refers to the stem or stalk-like feature supporting the cap of a mushroom. Like all tissues of the mushroom other than the hymenium, the stipe is composed of sterile hyphal...

 is up to 5 cm (2 in) long and has yellow-brown spots. When it is cut or injured, the mushroom oozes a white latex
Latex
Latex is the stable dispersion of polymer microparticles in an aqueous medium. Latexes may be natural or synthetic.Latex as found in nature is a milky fluid found in 10% of all flowering plants . It is a complex emulsion consisting of proteins, alkaloids, starches, sugars, oils, tannins, resins,...

, 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 mycorrhiza
Mycorrhiza
A mycorrhiza is a symbiotic association between a fungus and the roots of a vascular plant....

l associations with various coniferous trees species, such as spruce
Spruce
A spruce is a tree of the genus Picea , a genus of about 35 species of coniferous evergreen trees in the Family Pinaceae, found in the northern temperate and boreal regions of the earth. Spruces are large trees, from tall when mature, and can be distinguished by their whorled branches and conical...

, pine
Pine
Pines are trees in the genus Pinus ,in the family Pinaceae. They make up the monotypic subfamily Pinoideae. There are about 115 species of pine, although different authorities accept between 105 and 125 species.-Etymology:...

 and fir
Fir
Firs are a genus of 48–55 species of evergreen conifers in the family Pinaceae. They are found through much of North and Central America, Europe, Asia, and North Africa, occurring in mountains over most of the range...

, and deciduous
Deciduous
Deciduous means "falling off at maturity" or "tending to fall off", and is typically used in reference to trees or shrubs that lose their leaves seasonally, and to the shedding of other plant structures such as petals after flowering or fruit when ripe...

 species such as oak
Oak
An oak is a tree or shrub in the genus Quercus , of which about 600 species exist. "Oak" may also appear in the names of species in related genera, notably Lithocarpus...

 and alder
Alder
Alder is the common name of a genus of flowering plants belonging to the birch family . The genus comprises about 30 species of monoecious trees and shrubs, few reaching large size, distributed throughout the North Temperate Zone and in the Americas along the Andes southwards to...

. It has also been collected in India. Two varieties have been named: var. pitkinensis, known from Colorado
Colorado
Colorado is a U.S. state that encompasses much of the Rocky Mountains as well as the northeastern portion of the Colorado Plateau and the western edge of the Great Plains...

, and var. pungens, from Michigan
Michigan
Michigan is a U.S. state located in the Great Lakes Region of the United States of America. The name Michigan is the French form of the Ojibwa word mishigamaa, meaning "large water" or "large lake"....

.

Taxonomy

The species was originally described by American mycologist Alexander H. Smith
Alexander H. Smith
Alexander Hanchett Smith was an American mycologist known for his extensive contributions to the taxonomy and phylogeny of the higher fungi, especially the agarics.-Early life:...

 in 1960, from a collection made near Warm Lake
Warm Lake
Warm Lake is a popular lake in Idaho, United States. It is located 26 miles east of Cascade in Valley County, at 5,298 feet above sea level.The lake's abundance of wildlife makes it very popular for camping, fishing and hunting. Visitors typically have a chance of seeing moose, deer, bear, elk,...

, Idaho
Idaho
Idaho is a state in the Rocky Mountain area of the United States. The state's largest city and capital is Boise. Residents are called "Idahoans". Idaho was admitted to the Union on July 3, 1890, as the 43rd state....

, two years prior. The species was originally collected under alders with conifers nearby, and its specific epithet reflects the presumed association between the species—alnicola means "living with alder". Researchers subsequently discovered that the species has a relationship with conifers, not with alders, as the name implies. The mushroom is commonly
Common name
A common name of a taxon or organism is a name in general use within a community; it is often contrasted with the scientific name for the same organism...

 known as the "golden milkcap".

Lactarius alnicola is classified in subsection Scrobiculati of section Piperites in the genus Lactarius
Lactarius
Lactarius is a genus of mushroom-producing fungi. The genus, collectively known commonly as milk-caps, are characterized by the fact that they exude a milky fluid if cut or damaged...

. Species in this subsection are characterized by having a milk-white to creamy or whey-like latex
Latex
Latex is the stable dispersion of polymer microparticles in an aqueous medium. Latexes may be natural or synthetic.Latex as found in nature is a milky fluid found in 10% of all flowering plants . It is a complex emulsion consisting of proteins, alkaloids, starches, sugars, oils, tannins, resins,...

 that soon turns yellow upon exposure to air, and which may stain freshly cut surfaces of the fruit body yellow. Further, the cap margin is bearded, strigose (covered with sharp, straight, and stiff hairs), and coarsely tomentose
Tomentose
Tomentose is a term used to describe plant hairs that are flattened and matted, forming a woolly coating known as tomentum. Often the hairs are silver or gray-colored...

 or woolly when young. Other species in the subsection include L. subpaludosus, L. delicatus, L. torminosus
Lactarius torminosus
Lactarius torminosus, commonly known as the woolly milkcap or the bearded milkcap, is a large basidiomycete fungus in the genus Lactarius. It is found in the United Kingdom, Northern Europe, and is common in North America, where it grows in mixed forests in a mycorrhizal association with various...

, L. payettensis, L. gossypinus, L. pubescens
Lactarius pubescens
Lactarius pubescens, commonly known as the downy milk cap, is a species of fungus in the Russulaceae family. It is a medium to large agaric with a creamy-buff, hairy cap, whitish gills and short stout stem...

, L. resimus
Lactarius resimus
Lactarius resimus is a species of mushrooms in the genus Lactarius, which is considered a delicacy in Russia and some other countries of Eastern Europe when pickled in salt. There it is considered one of three tastiest edible mushrooms, along with Boletus edulis and Lactarius deliciosus, though it...

and L. scrobiculatus
Lactarius scrobiculatus
Lactarius scrobiculatus 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 type species
Type species
In biological nomenclature, a type species is both a concept and a practical system which is used in the classification and nomenclature of animals and plants. The value of a "type species" lies in the fact that it makes clear what is meant by a particular genus name. A type species is the species...

 of the subsection).

Description

The cap
Pileus (mycology)
The pileus is the technical name for the cap, or cap-like part, of a basidiocarp or ascocarp that supports a spore-bearing surface, the hymenium. The hymenium may consist of lamellae, tubes, or teeth, on the underside of the pileus...

 is 8 – wide, initially convex but becoming depressed to funnel-shaped in maturity. The cap margin is initially rolled inward, then becomes uplifted as the cap expands. The cap surface is sticky to slimy, and near the margin there are matted "hairs" beneath the slimy or sticky layer. The color of the cap surface is yellow-ochre
Ochre
Ochre is the term for both a golden-yellow or light yellow brown color and for a form of earth pigment which produces the color. The pigment can also be used to create a reddish tint known as "red ochre". The more rarely used terms "purple ochre" and "brown ochre" also exist for variant hues...

, sometimes with concentric bands of lighter and darker shades; the color becomes paler near the margin. The gills are adnate (squarely attached to the stem) to decurrent (attached to and running down the length of the stem), narrow, and crowded closely together. Forked near the stem
Stipe (mycology)
thumb|150px|right|Diagram of a [[basidiomycete]] stipe with an [[annulus |annulus]] and [[volva |volva]]In mycology a stipe refers to the stem or stalk-like feature supporting the cap of a mushroom. Like all tissues of the mushroom other than the hymenium, the stipe is composed of sterile hyphal...

, the gills are initially whitish before becoming pale ochraceous-buff. There are many lamellulae—small gills that do not extend completely to the stem.

The stem is 3 – long and 2 – thick, nearly equal in width throughout or tapered downward, dry, hard, coarsely pitted, and whitish to cream yellowish. It is initially solid, then becomes hollow with age. The flesh
Trama (mycology)
In mycology trama is a term for the inner, fleshy portion of a mushroom's basidiocarp, or fruit body. It is distinct from the outer layer of tissue, known as the pileipellis or cuticle, and from the spore-bearing tissue layer known as the hymenium....

 is thick, hard, whitish, and slowly stains pale yellow after the mushroom has been cut open. It has no distinctive odor, while the taste is immediately acrid. The latex
Latex
Latex is the stable dispersion of polymer microparticles in an aqueous medium. Latexes may be natural or synthetic.Latex as found in nature is a milky fluid found in 10% of all flowering plants . It is a complex emulsion consisting of proteins, alkaloids, starches, sugars, oils, tannins, resins,...

 is sparse, white on exposure to air, and unchanging or very slowly changing color to yellow. It stains cut flesh yellow, and tastes acrid. According to mycologist David Arora
David Arora
David Arora is an American mycologist, naturalist, and writer. He is the author of two popular books on mushroom identification, Mushrooms Demystified and All That the Rain Promises and More.......

, the oak-loving central and southern Californian population of this species has a more latent acrid taste. The spore print
Spore print
thumb|300px|right|Making a spore print of the mushroom Volvariella volvacea shown in composite: mushroom cap laid on white and dark paper; cap removed after 24 hours showing pinkish-tan spore print...

 may range slightly in color: thin deposits are white, thick deposits are more yellow. The mushroom is considered inedible because of the intensely peppery taste.

Microscopic characters

The spore
Spore
In biology, a spore is a reproductive structure that is adapted for dispersal and surviving for extended periods of time in unfavorable conditions. Spores form part of the life cycles of many bacteria, plants, algae, fungi and some protozoa. According to scientist Dr...

s are 7.5–10 by 6–8.5 µm
Micrometre
A micrometer , is by definition 1×10-6 of a meter .In plain English, it means one-millionth of a meter . Its unit symbol in the International System of Units is μm...

, ellipsoid, and ornamented with warts and narrow bands that form a partial reticulum. The surface prominences are up to 1 µm high, but mostly in the range 0.3–0.6 µm. The spores are hyaline
Hyaline
The term hyaline denotes a substance with a glass-like appearance.-Histopathology:In histopathological medical usage, a hyaline substance appears glassy and pink after being stained with haematoxylin and eosin — usually it is an acellular, proteinaceous material...

 (translucent) and amyloid
Amyloid (mycology)
In mycology the term amyloid refers to a crude chemical test using iodine in either Melzer's reagent or Lugol's solution, to produce a black to blue-black positive reaction. It is called amyloid because starch gives a similar reaction, and that reaction for starch is also called an amyloid reaction...

, meaning that they will adsorb iodine
Iodine
Iodine is a chemical element with the symbol I and atomic number 53. The name is pronounced , , or . The name is from the , meaning violet or purple, due to the color of elemental iodine vapor....

 when stained with Melzer's reagent
Melzer's Reagent
Melzer's reagent is a chemical reagent used by mycologists to assist with the identification of fungi.-Composition:...

. The basidia, the spore-bearing cells, are four-spored, and measure 37–48 by 8–11 µm. The cap cuticle
Pileipellis
thumb|300px||right|The cuticle of some mushrooms, such as [[Russula mustelina]] shown here, can be peeled from the cap, and may be useful as an identification feature....

 is an ixocutis (a tissue layer on the surface of a mushroom made of a layer of gelatinous hypha
Hypha
A hypha is a long, branching filamentous structure of a fungus, and also of unrelated Actinobacteria. In most fungi, hyphae are the main mode of vegetative growth, and are collectively called a mycelium; yeasts are unicellular fungi that do not grow as hyphae.-Structure:A hypha consists of one or...

e) made of encrusted hyphae that are 3–5 µm wide.

Varieties

In their 1979 monograph
Monograph
A monograph is a work of writing upon a single subject, usually by a single author.It is often a scholarly essay or learned treatise, and may be released in the manner of a book or journal article. It is by definition a single document that forms a complete text in itself...

 of North American Lactarius species, Hesler
Lexemuel Ray Hesler
-External links:* Finding Aid for the Lexemuel Ray Hesler Collection, 1899-1982...

 and Smith named two varieties of L. alnicola. Lactarius alnicola var. pitkinensis, reported under mixed aspen and conifers from Ashcroft, Colorado
Ashcroft, Colorado
Ashcroft originally known as Castle Forks City and then Chloride until 1882, was a mining town located ten miles south of Aspen near Castle Creek, in Pitkin County, Colorado, United States. A few buildings remain standing as a testament to the town's past.-The early years:In the spring of 1880 two...

, is very similar to the nominate variety, but it has a white to cream-colored cap and white, unchanging latex. It has slightly smaller fruit bodies, with caps up to 10 cm (3.9 in) wide, and stems up to 4 cm (1.6 in) long; its spores are slightly larger, measuring 9–10.5 by 7.5–9 µm. Lactarius alnicola var. pungens, reported only from mixed forests in Michigan
Michigan
Michigan is a U.S. state located in the Great Lakes Region of the United States of America. The name Michigan is the French form of the Ojibwa word mishigamaa, meaning "large water" or "large lake"....

, is similar but has a tacky surface that soon dries, a dull ochraceous to ochraceous-tan cap with an ochraceous-tawny
Tawny (color)
Tawny is a yellowish brown color. The word means "tan-colored," from Anglo-Norman tauné "associated with the brownish-yellow of tanned leather," from Old French tané "to tan hides," from Medieval Latin tannare, from tannum "crushed oak bark," used in tanning leather, probably from a Celtic source...

 center. It has whitish flesh, with a pungent odor described as "distinct and peculiar".

Similar species

Novice mushroom hunters may mistake L. alnicola for the edible
Edible mushroom
Edible mushrooms are the fleshy and edible fruiting bodies of several species of fungi. Mushrooms belong to the macrofungi, because their fruiting structures are large enough to be seen with the naked eye. They can appear either below ground or above ground where they may be picked by hand...

 species Cantharellus cibarius, a choice edible
Edible mushroom
Edible mushrooms are the fleshy and edible fruiting bodies of several species of fungi. Mushrooms belong to the macrofungi, because their fruiting structures are large enough to be seen with the naked eye. They can appear either below ground or above ground where they may be picked by hand...

 species that has a vase-shaped fruit body with strongly decurrent gills. Other similar Lactarius species include L. zonarius, L. payettensis, L. yazooensis, L. olympianus, and L. psammicola f. glaber. L. olympianus also associates with conifers, and has a pale yellow-ochre, frequently zonate cap, but may be distinguished by its stem, which is usually covered with spots. L. payettensis has a roughened, not smooth, cap margin. L. yazooensis has a zonate cap and extremely acrid flesh. Its gills change color from pale vinaceous to light pinkish-brown in maturity. L. psammicola f. glaber has a pinkish-buff spore print. Mature fruit bodies of L. scrobiculatus var. montanus have been confused with L. alnicola. Its fruit bodies feature a smooth cap margin, acrid taste, white latex which slowly (over several minutes) turns yellow on exposure or stains the flesh yellow, and do not turn "clay color" when bruised.

Ecology, habitat, and distribution

Lactarius alnicola is an ectomycorrhizal species, and engages in a mutualistic association with certain plant species. In this association, the hypha
Hypha
A hypha is a long, branching filamentous structure of a fungus, and also of unrelated Actinobacteria. In most fungi, hyphae are the main mode of vegetative growth, and are collectively called a mycelium; yeasts are unicellular fungi that do not grow as hyphae.-Structure:A hypha consists of one or...

e of the fungus permeate large volumes of soil and obtain scarce elements
Chemical element
A chemical element is a pure chemical substance consisting of one type of atom distinguished by its atomic number, which is the number of protons in its nucleus. Familiar examples of elements include carbon, oxygen, aluminum, iron, copper, gold, mercury, and lead.As of November 2011, 118 elements...

, especially phosphorus
Phosphorus
Phosphorus is the chemical element that has the symbol P and atomic number 15. A multivalent nonmetal of the nitrogen group, phosphorus as a mineral is almost always present in its maximally oxidized state, as inorganic phosphate rocks...

—which is often limiting for plant growth—which they pass on to the plant in exchange for metabolic products of the plant's photosynthesis
Photosynthesis
Photosynthesis is a chemical process that converts carbon dioxide into organic compounds, especially sugars, using the energy from sunlight. Photosynthesis occurs in plants, algae, and many species of bacteria, but not in archaea. Photosynthetic organisms are called photoautotrophs, since they can...

. The ectomycorrhizae that the fungus forms in association with Picea engelmannii have been shown to contain lactifers (latex-producing cells) and pigment
Pigment
A pigment is a material that changes the color of reflected or transmitted light as the result of wavelength-selective absorption. This physical process differs from fluorescence, phosphorescence, and other forms of luminescence, in which a material emits light.Many materials selectively absorb...

s similar to the fruit body. Fruit bodies of the fungus grow in groups on the ground under alder
Alder
Alder is the common name of a genus of flowering plants belonging to the birch family . The genus comprises about 30 species of monoecious trees and shrubs, few reaching large size, distributed throughout the North Temperate Zone and in the Americas along the Andes southwards to...

s and conifers, usually appearing between July and October. It is a fairly common species in the western United States and Baja California
Baja California
Baja California officially Estado Libre y Soberano de Baja California is one of the 31 states which, with the Federal District, comprise the 32 Federal Entities of Mexico. It is both the northernmost and westernmost state of Mexico. Before becoming a state in 1953, the area was known as the North...

. Additional collection locations in Mexico include Veracruz
Veracruz
Veracruz, formally Veracruz de Ignacio de la Llave officially Estado Libre y Soberano de Veracruz de Ignacio de la Llave , is one of the 31 states that, along with the Federal District, comprise the 32 federative entities of Mexico. It is divided in 212 municipalities and its capital city is...

, Villarreal, and Tapia. A population in central and southern California is known to associate with oak
Oak
An oak is a tree or shrub in the genus Quercus , of which about 600 species exist. "Oak" may also appear in the names of species in related genera, notably Lithocarpus...

 trees. In the Rocky Mountains
Rocky Mountains
The Rocky Mountains are a major mountain range in western North America. The Rocky Mountains stretch more than from the northernmost part of British Columbia, in western Canada, to New Mexico, in the southwestern United States...

 it is associated with the subalpine
Subalpine
The subalpine zone is the biotic zone immediately below tree line around the world. Species that occur in this zone depend on the location of the zone on the Earth, for example, Snow Gum in Australia, or Subalpine Larch, Mountain Hemlock and Subalpine Fir in western North America.Trees in the...

 tree species Englemann Spruce (Picea engelmannii), while at lower elevations it is commonly found with white spruce (Picea glauca). It is also known to associate with Ponderosa Pine (Pinus ponderosa) and Douglas-fir (genus Pseudotsuga). The mushroom has also been collected from Bageshwar
Bageshwar
Bageshwar is a city and a municipal board in Bageshwar district in the state of Uttarakhand, India. It is also the administrative headquarters of Bageshwar district....

, in the state of Uttarakhand
Uttarakhand
Uttarakhand , formerly Uttaranchal, is a state in the northern part of India. It is often referred to as the Land of Gods due to the many holy Hindu temples and cities found throughout the state, some of which are among Hinduism's most spiritual and auspicious places of pilgrimage and worship...

, India.
The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
x
OK