''Lactarius indigo'', commonly known as the indigo milk cap, indigo milky, the indigo (or blue) lactarius, or the blue milk mushroom, is a species of
agaric fungus in the family
Russulaceae
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 ...
. A widely distributed species, it grows 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
In the fields of horticulture and Botany, the term ''deciduous'' () means "falling off at maturity" and "tending to fall off", in reference to trees and shrubs that seasonally shed leaves, usually in the autumn; to the shedding of petals, ...
and
coniferous forests, where it forms
mycorrhizal associations with a broad range of trees. The
fruit body
In botany, a fruit is the seed-bearing structure in flowering plants that is formed from the ovary after flowering.
Fruits are the means by which flowering plants (also known as angiosperms) disseminate their seeds. Edible fruits in particu ...
color ranges from dark blue in fresh specimens to pale blue-gray in older ones. The milk, or
latex
Latex is an emulsion (stable dispersion) of polymer microparticles in water. Latexes are found in nature, but synthetic latexes are common as well.
In nature, latex is found as a milky fluid found in 10% of all flowering plants (angiosperms ...
, that oozes when the mushroom tissue is cut or broken — a feature common to all members of the genus ''
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 ...
'' — is also
indigo
Indigo is a deep color close to the color wheel blue (a primary color in the RGB color space), as well as to some variants of ultramarine, based on the ancient dye of the same name. The word "indigo" comes from the Latin word ''indicum'', m ...
blue, but slowly turns green upon exposure to air. The
cap
A cap is a flat headgear, usually with a visor. Caps have crowns that fit very close to the head. They made their first appearance as early as 3200 BC. Caps typically have a visor, or no brim at all. They are popular in casual and informal se ...
has a diameter of , and the
stem is tall and 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 it's generally eaten with egg; generally as a side dish for a bigger meal.
Taxonomy and nomenclature
Originally described in 1822 as ''Agaricus indigo'' by American mycologist
Lewis David de Schweinitz
Lewis David de Schweinitz (13 February 1780 – 8 February 1834) was a German-American botanist and mycologist. He is considered by some the "Father of North American Mycology", but also made significant contributions to botany.
Education
...
,
[ the species was later transferred to the genus ''Lactarius'' in 1838 by the Swede Elias Magnus Fries.][ German botanist Otto Kuntze called it ''Lactifluus indigo'' in his 1891 treatise '']Revisio Generum Plantarum
''Revisio Generum Plantarum'', also known by its standard botanical abbreviation ''Revis. Gen. Pl.'', is a botanic treatise by Otto Kuntze. It was published in three volumes; the first two of these appeared in 1891, and the third was published in ...
'',[ but the suggested name change was not adopted by others. Hesler and ]Smith
Smith may refer to:
People
* Metalsmith, or simply smith, a craftsman fashioning tools or works of art out of various metals
* Smith (given name)
* Smith (surname), a family name originating in England, Scotland and Ireland
** List of people wi ...
in their 1960 study of North American species of ''Lactarius'' defined ''L. indigo'' as the type species
In zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the species that contains the biological type specime ...
of subsection ''Caerulei'', a group characterized by blue latex and a sticky, blue cap.[ In 1979, they revised their opinions on the organization of subdivisions in the genus ''Lactarius'', and instead placed ''L. indigo'' in subgenus ''Lactarius'' based on the color of latex, and the subsequent color changes observed after exposure to air. As they explained:]The gradual development of blue to violet pigmentation as one progresses from species to species is an interesting phenomenon deserving further study. The climax is reached in ''L. indigo'' which is blue throughout. ''L. chelidonium'' and its variety ''chelidonioides'', ''L. paradoxus'', and ''L. hemicyaneus'' may be considered as mileposts along the road to ''L. indigo''.
The specific epithet ''indigo'' is derived from the Latin
Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...
word meaning "indigo blue".[ Its names in the English ]vernacular
A vernacular or vernacular language is in contrast with a "standard language". It refers to the language or dialect that is spoken by people that are inhabiting a particular country or region. The vernacular is typically the native language, n ...
include the "indigo milk cap",[ the "indigo Lactarius",][ the "blue milk mushroom",][ and the "blue Lactarius".][ In central Mexico, it is known as ''añil'', ''azul'', ''hongo azul'', ''zuin'', and ''zuine''; it is also called ''quexque'' (meaning "blue") in ]Veracruz
Veracruz (), formally Veracruz de Ignacio de la Llave (), officially the Free and Sovereign State of Veracruz de Ignacio de la Llave ( es, Estado Libre y Soberano de Veracruz de Ignacio de la Llave), is one of the 31 states which, along with Me ...
and Puebla.[
]
Description
Like many other mushrooms, ''L. indigo'' develops from a nodule, that forms within the underground mycelium
Mycelium (plural mycelia) is a root-like structure of a fungus consisting of a mass of branching, thread-like hyphae. Fungal colonies composed of mycelium are found in and on soil and many other substrates. A typical single spore germinates ...
, a mass of threadlike fungal cells called hyphae that make up the bulk of the organism. Under appropriate environmental conditions of temperature, humidity, and nutrient availability, the visible reproductive structures (fruit bodies
The sporocarp (also known as fruiting body, fruit body or fruitbody) of fungi is a multicellular structure on which spore-producing structures, such as basidia or asci, are borne. The fruitbody is part of the sexual phase of a fungal life cyc ...
) are formed. The cap
A cap is a flat headgear, usually with a visor. Caps have crowns that fit very close to the head. They made their first appearance as early as 3200 BC. Caps typically have a visor, or no brim at all. They are popular in casual and informal se ...
of the fruit body, measuring between in diameter, is initially convex and later develops a central depression; in age it becomes even more deeply depressed, becoming somewhat funnel-shaped as the edge of the cap lifts upward. The margin of the cap is rolled inwards when young, but unrolls and elevates as it matures. The cap surface is indigo blue when fresh, but fades to a paler grayish- or silvery-blue, sometimes with greenish splotches. It is often