Honey fungus

Honey fungus

name = Armillaria
image_width = 250px
image_caption = Honey mushrooms
"Armillaria sp." (Armillaria)
regnum = Fungi
divisio = Basidiomycota
classis = Agaricomycetes
ordo = Agaricales
familia = Marasmiaceae
genus = "Armillaria"
subdivision_ranks = Species
subdivision =
name = Armillaria sp.
whichGills = adnate
capShape = convex

Honey fungus or "Armillaria" is a genus of parasitic fungi that live on trees and woody shrubs. It includes about 10 species formerly lumped together as "A. mellea".

"Armillaria" is long lived and form some of the largest living organisms in the world. The largest single organism (of the species "Armillaria ostoyae") covers more than 3.4 square miles (8.9 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" (mycorrhizal) 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.

Honey mushrooms

The fruiting bodies of the fungus are mushrooms that grow on wood, typically in cestipose clusters. The cap is 3–15 cm in diameter, typically has a honey yellow-brown color, and is covered with small dark scales. The stem may or may not have a ring. All "Armillaria" species have a white spore print and none have a volva (see "Amanita").

Honey mushrooms are edible and are easy to identify. Grossly similar species include "Pholiota" sp. which also grow in cestipose clusters on wood and fruit in the fall. However "Pholiota" sp. 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 " sp. which can grow side by side with "Armillaria" sp. also on wood. "Galerina" has a dark brown spore print and is deadly poisonous (alpha-amanitin) – see: Mushroom poisoning. There are some reports of temporary stomach problems, especially when eaten raw.

Honey fungus as a plant disease (white rot root disease)

Honey fungus is a potentially fatal pathogenic organism that affects trees, shrubs, 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 roots 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 mushrooms, 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. If further confirmation is required, it is advisable to seek the advice of a qualified tree surgeon (ISA Certified Arborist).

ee also

* Bioluminescence
* Foxfire

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Look at other dictionaries:

  • honey fungus — (also honey mushroom) noun a parasitic fungus producing honey coloured toadstools at the base of trees. [Armillaria mellea.] …   English new terms dictionary

  • honey fungus — noun a honey colored edible mushroom commonly associated with the roots of trees in late summer and fall; do not eat raw • Syn: ↑honey mushroom, ↑Armillariella mellea • Hypernyms: ↑agaric • Member Holonyms: ↑Armillariella, ↑genu …   Useful english dictionary

  • honey fungus — noun A parasitic mushroom of the genus Armillaria that lives on trees and shrubs …   Wiktionary

  • honey — n. (pl. eys) 1 a sweet sticky yellowish fluid made by bees and other insects from nectar collected from flowers. 2 the colour of this. 3 a sweetness. b a sweet thing. 4 a person or thing excellent of its kind. 5 esp. US (usu. as a form of… …   Useful english dictionary

  • honey mushroom — noun a honey colored edible mushroom commonly associated with the roots of trees in late summer and fall; do not eat raw • Syn: ↑honey fungus, ↑Armillariella mellea • Hypernyms: ↑agaric • Member Holonyms: ↑Armillariella, ↑genus Ar …   Useful english dictionary

  • fungus — fungic /fun jik/, adj. funguslike, adj. /fung geuhs/, n., pl. fungi /fun juy, fung guy/, funguses, adj. n. 1. any of a diverse group of eukaryotic single celled or multinucleate organisms that live by decomposing and absorbing the organic… …   Universalium

  • honey mushroom — the edible mushroom of the oak root fungus, Armillariella mellea. Cf. oak root rot. [1935 40] * * * …   Universalium

  • Wood-decay fungus — A wood decay fungus is a variety of fungus which has the ability to digest wood, causing it to rot. Wood decay fungi include those which attack dead wood, such as dry rot, and those which are parasitic on living trees, such as Armillaria (Honey… …   Wikipedia

  • shoestring fungus — noun any of several fungi of the genus Armillaria that form brown stringy rhizomorphs and cause destructive rot of the roots of some trees such as apples or maples • Hypernyms: ↑agaric • Member Holonyms: ↑Armillaria, ↑genus Armillaria * * * noun …   Useful english dictionary

  • bootlace fungus — noun Honey fungus • • • Main Entry: ↑boot …   Useful english dictionary

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