Honey fungus
Encyclopedia
Honey fungus, or Armillaria or оpenky , is a genus
of parasitic fungi that live on trees and woody shrubs. It includes about 10 species
formerly lumped together as A. mellea. Armillarias are long lived and form some of the largest living organisms
in the world. The largest single organism (of the species Armillaria solidipes) covers more than 3.4 square miles (8.8 km²) and is thousands of years old. Some species of Armillaria are bioluminescent
and may be responsible for the phenomena known as foxfire
and perhaps will o' the wisp
.
As a forest pathogen, Armillaria can be very destructive. It is responsible for the "white rot" root disease
(see below) of forests and is distinguished from Tricholoma (mycorrhiza
l) by this parasitic nature. Its high destructiveness comes from the fact that, unlike most parasites, it doesn't need to moderate its growth in order to avoid killing its host, since it will continue to thrive on the dead material.
In the Canadian Prairies
(particularly Manitoba), the term "honey fungus" is unknown to many; due to the large presence of Ukrainian Canadians in this area, the fungus is often referred to as pidpenky , from the Ukrainian term, "beneath the stump".
The fruit bodies
of the fungus are mushroom
s that grow on wood, typically in small dense clumps or tufts. Their caps
are typically yellow-brown, somewhat sticky to touch when moist, and, depending on age, may range in shape from conical to convex to depressed in the center. The stem
may or may not have a ring
. All Armillaria species have a white spore print
and none have a volva
(compare Amanita
).
Grossly similar species include Pholiota
spp. which also grow in cespitose clusters on wood and fruit in the fall. However Pholiota spp. have a yellowish to greenish yellow cast and a dark brown to grey-brown spore print. Mushroom hunters need to be especially wary of Galerina
spp. which can grow side by side with Armillaria spp. also on wood. Galerina
has a dark brown spore print and is deadly poisonous (alpha-amanitin
) – see: mushroom poisoning
.
ic organism that affects tree
s, shrub
s, woody climbers and, rarely, woody herbaceous perennials. Honey fungus grows on living trees as well as on dead and decaying woody material.
Honey fungus spreads both from living trees, dead and live root
s and stumps by means of reddish-brown to black root-like rhizomorphs ('bootlaces') at the rate of around 1 m a year, although infection by root contact is also possible. Infection by spores is rare. Rhizomorphs grow relatively close to the soil
surface (in the top 20 cm) and invade new roots, or the root collar (where the roots meet the stem) of woody plants. An infected tree will die once the fungus has girdled it, or when extensive root death has occurred. This can happen rapidly, or may take several years. Infected plants will deteriorate, although may exhibit prolific flower
or fruit
production shortly before death.
Initial symptoms of honey fungus infection include the dying back of leafy branches or failure of leaves to appear in spring. Black bootlace-like strands appear under the bark
and around the tree, and fruiting bodies grow in clusters from the infected plant in autumn and die back after the first frost. However these signs do not necessarily mean that the pathogenic (disease causing) strains of honey fungus are a cause of plant decline or death, so other identification methods are advised before a diagnosis is made. The presence of thin sheets of cream coloured mycelium
, giving off a strong smell of mushroom
s, beneath the bark at the base of the trunk or stem, sometimes extending upwards, or a gum or resin exuding from cracks in the bark of conifers, indicates that honey fungus is a likely cause of problems.
s and chanterelle
s and only the cep / porchini
is more highly prized. However pidpenky must be thoroughly cooked as they are mildly poisonous raw. Additionally one of the four UK species identified can lead to sickness when ingested with alcohol. Therefore for the non expert mycologist it is advisable not to drink alcohol for 12 hours before and 24 after eating this mushroom to avoid any possible nausea and vomiting. However if these sensible rules are followed this variety of mushroom is a delicacy with a strong distinctive mushroomy and nutty flavour. Recommended reference text for identification are Collins Complete British Mushrooms and Toadstools for the variety of field pictures in it and Roger Philips Mushrooms for the quality of his out of field pictures and descriptions.
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
of parasitic fungi that live on trees and woody shrubs. It includes about 10 species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
formerly lumped together as A. mellea. Armillarias are long lived and form some of the largest living organisms
Largest organisms
The largest organism found on Earth can be measured using a variety of methods. It could be defined as the largest by volume, mass, height or length. Some organisms group together to form a superorganism, though this cannot truly be classed as one large organism...
in the world. The largest single organism (of the species Armillaria solidipes) covers more than 3.4 square miles (8.8 km²) and is thousands of years old. Some species of Armillaria are bioluminescent
Bioluminescence
Bioluminescence is the production and emission of light by a living organism. Its name is a hybrid word, originating from the Greek bios for "living" and the Latin lumen "light". Bioluminescence is a naturally occurring form of chemiluminescence where energy is released by a chemical reaction in...
and may be responsible for the phenomena known as foxfire
Foxfire (bioluminescence)
Foxfire, also sometimes referred to as "fairy fire", is the bioluminescence created by some species of fungi present in decaying wood. The bluish green glow is attributed to luciferase, an oxidizing agent, which emits light as it reacts with luciferin...
and perhaps will o' the wisp
Will o' the wisp
A will-o'-the-wisp or ignis fatuus , also called a "will-o'-wisp", "jack-o'-lantern" , "hinkypunk", "corpse candle", "ghost-light", "spook-light", "fairy light", "friar's lantern", "hobby lantern", "ghost orb", or simply "wisp", is a ghostly light or lights sometimes seen at night or twilight over...
.
As a forest pathogen, Armillaria can be very destructive. It is responsible for the "white rot" root disease
Armillaria root rot
thumb|right|[[Armillaria luteobubalina]], widespread in Australia, is a primary cause of [[Eucalyptus]] tree death and [[forest dieback]] resulting from Armillaria root rot....
(see below) of forests and is distinguished from Tricholoma (mycorrhiza
Mycorrhiza
A mycorrhiza is a symbiotic association between a fungus and the roots of a vascular plant....
l) by this parasitic nature. Its high destructiveness comes from the fact that, unlike most parasites, it doesn't need to moderate its growth in order to avoid killing its host, since it will continue to thrive on the dead material.
In the Canadian Prairies
Canadian Prairies
The Canadian Prairies is a region of Canada, specifically in western Canada, which may correspond to several different definitions, natural or political. Notably, the Prairie provinces or simply the Prairies comprise the provinces of Alberta, Saskatchewan, and Manitoba, as they are largely covered...
(particularly Manitoba), the term "honey fungus" is unknown to many; due to the large presence of Ukrainian Canadians in this area, the fungus is often referred to as pidpenky , from the Ukrainian term, "beneath the stump".
Description
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...
of the fungus are 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...
s that grow on wood, typically in small dense clumps or tufts. Their caps
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...
are typically yellow-brown, somewhat sticky to touch when moist, and, depending on age, may range in shape from conical to convex to depressed in the center. 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...
may or may not have a ring
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...
. All Armillaria species have a white 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...
and none have a volva
Volva (mycology)
The volva is a mycological term to describe a cup-like structure at the base of a mushroom that is a remnant of the universal veil. This macrofeature is important in wild mushroom identification due to it being an easily observed, taxonomically significant feature which frequently signifies a...
(compare Amanita
Amanita
The genus Amanita contains about 600 species of agarics including some of the most toxic known mushrooms found worldwide. This genus is responsible for approximately 95% of the fatalities resulting from mushroom poisoning, with the death cap accounting for about 50% on its own...
).
Grossly similar species include Pholiota
Pholiota
Pholiota is a genus of small to fleshy mushrooms in the family Strophariaceae. The genus has a widespread distribution, especially in temperate regions, and contains about 150 species....
spp. which also grow in cespitose clusters on wood and fruit in the fall. However Pholiota spp. have a yellowish to greenish yellow cast and a dark brown to grey-brown spore print. Mushroom hunters need to be especially wary of Galerina
Galerina
Galerina is a genus of small brown-spored saprobic mushrooms, with over 300 species found throughout the world, from the far north to remote Macquarie Island in the Southern Ocean. Species are typically small and hygrophanous, with a slender and brittle stem. They are often found growing on wood,...
spp. which can grow side by side with Armillaria spp. also on wood. Galerina
Galerina
Galerina is a genus of small brown-spored saprobic mushrooms, with over 300 species found throughout the world, from the far north to remote Macquarie Island in the Southern Ocean. Species are typically small and hygrophanous, with a slender and brittle stem. They are often found growing on wood,...
has a dark brown spore print and is deadly poisonous (alpha-amanitin
Alpha-amanitin
alpha-Amanitin or α-amanitin is a cyclic peptide of eight amino acids. It is possibly the most deadly of all the amatoxins, toxins found in several species of the Amanita genus of mushrooms, one being the Death cap as well as the Destroying angel, a complex of similar species, principally A....
) – see: mushroom poisoning
Mushroom poisoning
Mushroom poisoning refers to harmful effects from ingestion of toxic substances present in a mushroom. These symptoms can vary from slight gastrointestinal discomfort to death. The toxins present are secondary metabolites produced in specific biochemical pathways in the fungal cells...
.
Plant pathology
Honey fungus, a "white rot" fungus, is a pathogenPathogen
A pathogen gignomai "I give birth to") or infectious agent — colloquially, a germ — is a microbe or microorganism such as a virus, bacterium, prion, or fungus that causes disease in its animal or plant host...
ic organism that affects tree
Tree
A tree is a perennial woody plant. It is most often defined as a woody plant that has many secondary branches supported clear of the ground on a single main stem or trunk with clear apical dominance. A minimum height specification at maturity is cited by some authors, varying from 3 m to...
s, shrub
Shrub
A shrub or bush is distinguished from a tree by its multiple stems and shorter height, usually under 5–6 m tall. A large number of plants may become either shrubs or trees, depending on the growing conditions they experience...
s, woody climbers and, rarely, woody herbaceous perennials. Honey fungus grows on living trees as well as on dead and decaying woody material.
Honey fungus spreads both from living trees, dead and live root
Root
In vascular plants, the root is the organ of a plant that typically lies below the surface of the soil. This is not always the case, however, since a root can also be aerial or aerating . Furthermore, a stem normally occurring below ground is not exceptional either...
s and stumps by means of reddish-brown to black root-like rhizomorphs ('bootlaces') at the rate of around 1 m a year, although infection by root contact is also possible. Infection by spores is rare. Rhizomorphs grow relatively close to the soil
Soil
Soil is a natural body consisting of layers of mineral constituents of variable thicknesses, which differ from the parent materials in their morphological, physical, chemical, and mineralogical characteristics...
surface (in the top 20 cm) and invade new roots, or the root collar (where the roots meet the stem) of woody plants. An infected tree will die once the fungus has girdled it, or when extensive root death has occurred. This can happen rapidly, or may take several years. Infected plants will deteriorate, although may exhibit prolific flower
Flower
A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants . The biological function of a flower is to effect reproduction, usually by providing a mechanism for the union of sperm with eggs...
or fruit
Fruit
In broad terms, a fruit is a structure of a plant that contains its seeds.The term has different meanings dependent on context. In non-technical usage, such as food preparation, fruit normally means the fleshy seed-associated structures of certain plants that are sweet and edible in the raw state,...
production shortly before death.
Initial symptoms of honey fungus infection include the dying back of leafy branches or failure of leaves to appear in spring. Black bootlace-like strands appear under the bark
Bark
Bark is the outermost layers of stems and roots of woody plants. Plants with bark include trees, woody vines and shrubs. Bark refers to all the tissues outside of the vascular cambium and is a nontechnical term. It overlays the wood and consists of the inner bark and the outer bark. The inner...
and around the tree, and fruiting bodies grow in clusters from the infected plant in autumn and die back after the first frost. However these signs do not necessarily mean that the pathogenic (disease causing) strains of honey fungus are a cause of plant decline or death, so other identification methods are advised before a diagnosis is made. The presence of thin sheets of cream coloured mycelium
Mycelium
thumb|right|Fungal myceliaMycelium is the vegetative part of a fungus, consisting of a mass of branching, thread-like hyphae. The mass of hyphae is sometimes called shiro, especially within the fairy ring fungi. Fungal colonies composed of mycelia are found in soil and on or within many other...
, giving off a strong smell of 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...
s, beneath the bark at the base of the trunk or stem, sometimes extending upwards, or a gum or resin exuding from cracks in the bark of conifers, indicates that honey fungus is a likely cause of problems.
Edibility
Edible - Choice. Honey Fungus or pidpenky are considered in Ukraine to be one of the best wild mushrooms and highly prized. They are commonly ranked above morelMorel
Morchella, the true morels, is a genus of edible mushrooms closely related to anatomically simpler cup fungi. These distinctive mushrooms appear honeycomb-like in that the upper portion is composed of a network of ridges with pits between them....
s and chanterelle
Chanterelle
Cantharellus cibarius, commonly known as the chanterelle, golden chanterelle or girolle, is a fungus. It is probably the best known species of the genus Cantharellus, if not the entire family of Cantharellaceae. It is orange or yellow, meaty and funnel-shaped...
s and only the cep / porchini
Boletus edulis
Boletus edulis, commonly known as penny bun, porcino or cep, is a basidiomycete fungus, and the type species of the genus Boletus. Widely distributed in the Northern Hemisphere across Europe, Asia, and North America, it does not occur naturally in the Southern Hemisphere, although it has been...
is more highly prized. However pidpenky must be thoroughly cooked as they are mildly poisonous raw. Additionally one of the four UK species identified can lead to sickness when ingested with alcohol. Therefore for the non expert mycologist it is advisable not to drink alcohol for 12 hours before and 24 after eating this mushroom to avoid any possible nausea and vomiting. However if these sensible rules are followed this variety of mushroom is a delicacy with a strong distinctive mushroomy and nutty flavour. Recommended reference text for identification are Collins Complete British Mushrooms and Toadstools for the variety of field pictures in it and Roger Philips Mushrooms for the quality of his out of field pictures and descriptions.
See also
- List of Armillaria species
- BioluminescenceBioluminescenceBioluminescence is the production and emission of light by a living organism. Its name is a hybrid word, originating from the Greek bios for "living" and the Latin lumen "light". Bioluminescence is a naturally occurring form of chemiluminescence where energy is released by a chemical reaction in...
- FoxfireFoxfire (bioluminescence)Foxfire, also sometimes referred to as "fairy fire", is the bioluminescence created by some species of fungi present in decaying wood. The bluish green glow is attributed to luciferase, an oxidizing agent, which emits light as it reacts with luciferin...
External links
- Armillaria at Index FungorumIndex FungorumIndex Fungorum, an international project to index all formal names in the Fungi Kingdom. Somewhat comparable to the IPNI, but with more contributing institutions....