Boletus bicolor
Encyclopedia
Boletus bicolor, also known in English as the two-colored bolete or red and yellow bolete after its two-tone coloring scheme of red and yellow, is an edible fungus
of the Boletus
genus that inhabits most of eastern North America
, primarily east of the Rocky Mountains
and in season during the summer and fall months but can be found across the globe in China and Nepal. Its fruit body, the mushroom
, is classed as medium or large in size, which helps distinguish it from the many similar appearing species that have a smaller stature. A deep blue/indigo bruising of the pore surface and a less dramatic bruising coloration change in the stem
over a period of several minutes are identifying characteristics that distinguish it from the similar poisonous species Boletus sensibilis
. The are two variations of this species, var. borealis and var. subreticulatus, and several other similar species of fungi are not poisonous.
of the two-colored bolete
varies from light red and almost pink to brick red. The most common coloration is brick red when mature. The cap usually ranges from 5 to 15 centimeters (2 to 6 inches) in width, with bright yellow pores underneath. The two-colored bolete is one of several types of boletes that has the unusual reaction of the pore surface
producing a dark blue/indigo when it is injured, although this takes longer than it does with other mushrooms. When the flesh
is exposed it also turns a dark blue but less dramatically than the pore surface. When the fruit body
is young the pore surface is a bright yellow and with maturity it slowly turns a dingy yellow.
The stem of the two-colored bolete ranges from 5 to 10 centimeters (2 to 4 inches) in length and ranges from 1 to 3 centimeters (3/8 to 1 1/8 inches) in width. The stem coloration is yellow at the apex and a red or rosy red for the remaining two thirds. When injured it bruises blue very slowly and may hardly change color at all in some cases. The stem lacks an annulus
and has a partial veil
.
. With the application of FeSO4 to the cap cuticle (pileipellis
) the pileipellis will turn a dark grey, almost black color and with the application of Potassium hydroxide
(KOH) or NH4OH it will turn to a negative coloration. The context stains a bluish grey to an olive green when FeSO4 is applied to it, a pale orange to a pale yellow with the application of KOH, and negative with the application of NH4OH.
, which is poisonous and has many of the same visual characteristics of the two colored bolete.
, as far south as the Florida peninsula, and out to the Midwest as far as Wisconsin
. It is most commonly found in deciduous woodland
and usually grows under or close to broad-leaved tree
s, especially oak
. It can be found in isolation and in groups or clusters, primarily during the June through October months. The two-colored bolete is also found in China and Nepal; where it is one of the most used mushrooms of the total 228 species of edible mushrooms used in Nepal. This unusual distribution of the two colored bolete and other mushrooms is known as the Grayan disjunction; the phenomenon is characterized by a species living in one continent or island and then also on the other side of the world with no specimens of the species living in between the specific habitats. The Grayan Disjunction is not uncommon among fungi.
differs from the two-colored bolete in that it has an immediate bruising reaction and it is poisonous when ingested, causing stomach upset and in some cases a severe allergic reaction. B. miniato-olivaceus has a full yellow stem and slightly lighter cap coloration. It also has a more immediate bruising reaction than the two-colored bolete and the stem is slightly longer in proportion to the cap. Boletus peckii differs from the two colored bolete by having a smaller average size, a rose red cap that turns almost brown with age, having flesh that is paler in color, and a bitter taste. Boletus speciosus differs from the two colored bolete by having a fully reticulated stem, more brilliant colors, and very narrow cylindrical spores. Boletus rubeus and the two colored bolete have been found to have almost no difference between the two different species and they cannot be separated.
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...
of the Boletus
Boletus
Boletus is a genus of mushroom, comprising over 100 species. The genus Boletus was originally broadly defined and described by Elias Magnus Fries in 1821, essentially containing all fungi with pores...
genus that inhabits most of eastern North America
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
, primarily east of 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...
and in season during the summer and fall months but can be found across the globe in China and Nepal. Its fruit body, the mushroom
Mushroom
A mushroom is the fleshy, spore-bearing fruiting body of a fungus, typically produced above ground on soil or on its food source. The standard for the name "mushroom" is the cultivated white button mushroom, Agaricus bisporus; hence the word "mushroom" is most often applied to those fungi that...
, is classed as medium or large in size, which helps distinguish it from the many similar appearing species that have a smaller stature. A deep blue/indigo bruising of the pore surface and a less dramatic bruising coloration change in 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...
over a period of several minutes are identifying characteristics that distinguish it from the similar poisonous species Boletus sensibilis
Boletus sensibilis
Boletus sensibilis is a species of fungus in the Boletaceae family. The species was first described scientifically by American mycologist Charles Horton Peck in 1879....
. The are two variations of this species, var. borealis and var. subreticulatus, and several other similar species of fungi are not poisonous.
Description
The color of the capPileus (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...
of the two-colored bolete
Bolete
A bolete is a type of fungal fruiting body characterized by the presence of a pileus that is clearly differentiated from the stipe, with a spongy surface of pores on the underside of the pileus...
varies from light red and almost pink to brick red. The most common coloration is brick red when mature. The cap usually ranges from 5 to 15 centimeters (2 to 6 inches) in width, with bright yellow pores underneath. The two-colored bolete is one of several types of boletes that has the unusual reaction of the pore surface
Hymenium
The hymenium is the tissue layer on the hymenophore of a fungal fruiting body where the cells develop into basidia or asci, which produce spores. In some species all of the cells of the hymenium develop into basidia or asci, while in others some cells develop into sterile cells called cystidia or...
producing a dark blue/indigo when it is injured, although this takes longer than it does with other mushrooms. When 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 exposed it also turns a dark blue but less dramatically than the pore surface. When the fruit body
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...
is young the pore surface is a bright yellow and with maturity it slowly turns a dingy yellow.
The stem of the two-colored bolete ranges from 5 to 10 centimeters (2 to 4 inches) in length and ranges from 1 to 3 centimeters (3/8 to 1 1/8 inches) in width. The stem coloration is yellow at the apex and a red or rosy red for the remaining two thirds. When injured it bruises blue very slowly and may hardly change color at all in some cases. The stem lacks an annulus
Annulus (mycology)
An annulus is the ring like structure sometimes found on the stipe of some species of mushrooms. The annulus represents the remaining part of the partial veil, after it has ruptured to expose the gills or other spore-producing surface. An annulus may be thick and membranous, or it may be cobweb-like...
and has a partial veil
Partial veil
thumb|150px|right|Developmental stages of [[Agaricus campestris]] showing the role and evolution of a partial veilPartial veil is a mycological term used to describe a temporary structure of tissue found on the fruiting bodies of some basidiomycete fungi, typically agarics...
.
Macrochemical Tests
Further methods of identification are macrochemical testsChemical tests in mushroom identification
Chemical tests in mushroom identification are methods that aid in determining the variety of some fungi. The most useful tests are Melzer's reagent and potassium hydroxide.- Ammonia :Household ammonia can be used. A couple of drops are placed on the flesh...
. With the application of FeSO4 to the cap cuticle (pileipellis
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....
) the pileipellis will turn a dark grey, almost black color and with the application of Potassium hydroxide
Potassium hydroxide
Potassium hydroxide is an inorganic compound with the formula KOH, commonly called caustic potash.Along with sodium hydroxide , this colorless solid is a prototypical strong base. It has many industrial and niche applications. Most applications exploit its reactivity toward acids and its corrosive...
(KOH) or NH4OH it will turn to a negative coloration. The context stains a bluish grey to an olive green when FeSO4 is applied to it, a pale orange to a pale yellow with the application of KOH, and negative with the application of NH4OH.
Edibility
The two-colored bolete is a semi-edible mushroom. Some may have an allergic reaction after ingestion resulting in stomach upset. The two-colored bolete has a very mild to no taste although it is said to have a very distinctive taste like that of the King bolete. It can be cooked a variety of ways. The the varying color of the cap can be used to determinate if the mushroom is ready to be eaten. If the cap is a lighter red, then it is less mature and is in a stage where it is often larva infested or it can be soft fleshed, in some cases both. The cap should have a dark brick red color to be safe to eat. Drying the two-colored bolete is a good way of storing the mushroom. It is important to note the time it takes for the two-colored bolete to bruise when identifying it for consumption. It should take several minutes to bruise compared to the instant bruising of Boletus sensibilisBoletus sensibilis
Boletus sensibilis is a species of fungus in the Boletaceae family. The species was first described scientifically by American mycologist Charles Horton Peck in 1879....
, which is poisonous and has many of the same visual characteristics of the two colored bolete.
Microscopic characteristics
The spore deposit of the two colored bolete is olive brown, the spores are slightly oblong to ventricose at face view, measuring 8-11 (12)x3.5-4.5 (5)μ. In profile view the spores are obscurely unequilateral to oblong with a shallow suprahilar depression, nearly hyaline to pale dingy ochraceous when in KOH, and are smooth. The tube trauma is divergent and gelatinous from a single central strand, not amyloid, and will often stain yellow-brown when placed in KOH.Distribution and habitat
The two-colored bolete is distributed from southeastern Canada and the Great Lakes Region, primarily west of the Rocky MountainsRocky 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...
, as far south as the Florida peninsula, and out to the Midwest as far as Wisconsin
Wisconsin
Wisconsin is a U.S. state located in the north-central United States and is part of the Midwest. It is bordered by Minnesota to the west, Iowa to the southwest, Illinois to the south, Lake Michigan to the east, Michigan to the northeast, and Lake Superior to the north. Wisconsin's capital is...
. It is most commonly found in deciduous woodland
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...
and usually grows under or close to broad-leaved tree
Broad-leaved tree
A broad-leaved tree or broad-leaf tree or broadleaf tree is any tree that has wide leaves, rather than slim, needle-like leaves as found in conifers...
s, especially 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...
. It can be found in isolation and in groups or clusters, primarily during the June through October months. The two-colored bolete is also found in China and Nepal; where it is one of the most used mushrooms of the total 228 species of edible mushrooms used in Nepal. This unusual distribution of the two colored bolete and other mushrooms is known as the Grayan disjunction; the phenomenon is characterized by a species living in one continent or island and then also on the other side of the world with no specimens of the species living in between the specific habitats. The Grayan Disjunction is not uncommon among fungi.
Similar species
The two-colored bolete has several species that are similar to it and the differences are minute in most cases. B. sensibilisBoletus sensibilis
Boletus sensibilis is a species of fungus in the Boletaceae family. The species was first described scientifically by American mycologist Charles Horton Peck in 1879....
differs from the two-colored bolete in that it has an immediate bruising reaction and it is poisonous when ingested, causing stomach upset and in some cases a severe allergic reaction. B. miniato-olivaceus has a full yellow stem and slightly lighter cap coloration. It also has a more immediate bruising reaction than the two-colored bolete and the stem is slightly longer in proportion to the cap. Boletus peckii differs from the two colored bolete by having a smaller average size, a rose red cap that turns almost brown with age, having flesh that is paler in color, and a bitter taste. Boletus speciosus differs from the two colored bolete by having a fully reticulated stem, more brilliant colors, and very narrow cylindrical spores. Boletus rubeus and the two colored bolete have been found to have almost no difference between the two different species and they cannot be separated.
Variations
There are two variations of the two colored bolete; borealis and subreticulatus. Both variations have a very similar habitat to that of var. bicolor except that the variations appear to be limited to just the North American continent. Both variations also have a slightly different coloration than that of var. bicolor and both variations have pores that are deeper than that of var. bicolor. Neither variation is considered as edible as var. bicolor and are not as commonly used in regional recipes.See also
- List of Boletus species