Armillaria is a genus of fungi that includes the A. mellea species known as honey fungi that live on trees and woody shrubs. It includes about 10 species formerly categorized summarily as A. mellea. Armillarias are long-lived and form the largest living fungi in the world. The largest known organism covers more than 3.4 square miles (8.8 km2) in Oregon's Malheur National Forest and is estimated to be 2,500 years old. Some species of Armillaria display bioluminescence, resulting in foxfire.
Armillaria mellea, commonly known as honey fungus, is a basidiomycete fungus in the genus Armillaria. It is a plant pathogen and part of a cryptic species complex of closely related and morphologically similar species. It causes Armillaria root rot in many plant species and produces mushrooms around the base of trees it has infected. The symptoms of infection appear in the crowns of infected trees as discoloured foliage, reduced growth, dieback of the branches and death. The mushrooms are edible but some people may be intolerant to them. This species is capable of producing light via bioluminescence in its mycelium.
Mycelial cords are linear aggregations of parallel-oriented hyphae. The mature cords are composed of wide, empty vessel hyphae surrounded by narrower sheathing hyphae. Cords may look similar to plant roots, and also frequently have similar functions; hence they are also called rhizomorphs. As well as growing underground or on the surface of trees and other plants, some fungi make mycelial cords which hang in the air from vegetation.
Armillaria luteobubalina, commonly known as the Australian honey fungus, is a species of mushroom in the family Physalacriaceae. Widely distributed in southern Australia, the fungus is responsible for a disease known as Armillaria root rot, a primary cause of Eucalyptus tree death and forest dieback. It is the most pathogenic and widespread of the six Armillaria species found in Australia. The fungus has also been collected in Argentina and Chile. Fruit bodies have cream- to tan-coloured caps that grow up to 10 cm (4 in) in diameter and stems that measure up to 20 cm (8 in) long by 1.5 cm (1 in) thick. The fruit bodies, which appear at the base of infected trees and other woody plants in autumn (March–April), are edible, but require cooking to remove the bitter taste. The fungus is dispersed through spores produced on gills on the underside of the caps, and also by growing vegetatively through the root systems of host trees. The ability of the fungus to spread vegetatively is facilitated by an aerating system that allows it to efficiently diffuse oxygen through rhizomorphs—rootlike structures made of dense masses of hyphae.
Armillaria tabescens is a species of fungus in the family Physalacriaceae. It is a plant pathogen. The mycelium of the fungus is bioluminescent.
Silver leaf is a fungal disease of trees caused by the fungus plant pathogen Chondrostereum purpureum. It attacks most species of the rose family Rosaceae, particularly the genus Prunus. The disease is progressive and often fatal. The common name is taken from the progressive silvering of leaves on affected branches. It is spread by airborne spores landing on freshly exposed sapwood. For this reason cherries and plums are pruned in summer, when spores are least likely to be present and when disease is visible. Silver Leaf can also happen on poming fruits like apples and pears. Plums are especially vulnerable.
Rosellinia bunodes is a plant pathogen infecting several hosts including avocados, bananas, cacao and tea.
Armillaria fuscipes is a plant pathogen that causes Armillaria root rot on Pinus, coffee plants, tea and various hardwood trees. It is common in South Africa. The mycelium of the fungus is bioluminescent.
Pleurotus dryinus is a species of fungus in the family Pleurotaceae. It grows on dead wood and is also a weak pathogen; infecting especially broad-leaved trees.
Armillaria novae-zelandiae is a species of mushroom-forming fungus in the family Physalacriaceae. This plant pathogen species is one of three Armillaria species that have been identified in New Zealand.
Armillaria gallica is a species of honey mushroom in the family Physalacriaceae of the order Agaricales. The species is a common and ecologically important wood-decay fungus that can live as a saprobe, or as an opportunistic parasite in weakened tree hosts to cause root or butt rot. It is found in temperate regions of Asia, North America, and Europe. The species forms fruit bodies singly or in groups in soil or rotting wood. The fungus has been inadvertently introduced to South Africa. Armillaria gallica has had a confusing taxonomy, due in part to historical difficulties encountered in distinguishing between similar Armillaria species. The fungus received international attention in the early 1990s when an individual colony living in a Michigan forest was reported to cover an area of 15 hectares, weigh at least 95 tonnes, and be 1,500 years old. This individual is popularly known as the "humongous fungus", and is a tourist attraction and inspiration for an annual mushroom-themed festival in Crystal Falls. Recent studies have revised the fungus's age to 2,500 years and its size to about 400 tonnes, four times the original estimate.
Armillaria nabsnona is a species of fungus in the family Physalacriaceae. The species is found in the west coast of North America, Hawaii, and Japan, where it grows on decaying hardwoods, particularly species of alder. Its fruit bodies have convex to flattened orange-brown caps up to 7 cm in diameter, brown stipes, and whitish to pinkish-tan gills.
Forest pathology is the research of both biotic and abiotic maladies affecting the health of a forest ecosystem, primarily fungal pathogens and their insect vectors. It is a subfield of forestry and plant pathology.
Armillaria root rot is a fungal root rot caused by several different members of the genus Armillaria. The symptoms are variable depending on the host infected, ranging from stunted leaves to chlorotic needles and dieback of twigs and branches. However, all infected hosts display symptoms characteristic of being infected by a white rotting fungus. The most effective ways of management focus on limiting the spread of the fungus, planting resistant species, and removing infected material. This disease poses a threat to the lumber industry as well as affecting recreational areas.
Armillaria ostoyae is a species of fungus (mushroom), pathogenic to trees, in the family Physalacriaceae. In the western United States, it is the most common variant of the group of species under the name Armillaria mellea. A. ostoyae is common on both hardwood and conifer wood in forests west of the Cascade Range in Oregon, United States. It has decurrent gills and the stipe has a ring. The mycelium invades the sapwood and is able to disseminate over great distances under the bark or between trees in the form of black rhizomorphs ("shoestrings"). In most areas of North America, Armillaria ostoyae can be separated from other species by its physical features: cream-brown colors, prominent cap scales, and a well-developed stem ring distinguish it from other Armillaria.
Tricholoma vaccinum, commonly known as the russet scaly tricholoma, the scaly knight, or the fuzztop, is a fungus of the agaric genus Tricholoma. It produces medium-sized fruit bodies (mushrooms) that have a distinctive hairy reddish-brown cap with a shaggy margin when young. The cap, which can reach a diameter of up to 6.5 cm (2.6 in) wide, breaks up into flattened scales in maturity. It has cream-buff to pinkish gills with brown spots. Its fibrous, hollow stipe is white above and reddish brown below, and measures 4 to 7.5 cm long. Although young fruit bodies have a partial veil, it does not leave a ring on the stipe.
Brenda D. Wingfield is a South African Professor of genetics and Deputy Dean of the University of Pretoria. She is known for her genetic studies of fungal tree pathogens.
Rhizomorpha is a genus of fungi that was created for species known only by their mycelial cords ("rhizomorphs") and so impossible to classify within the normal taxonomic system, which is based on reproductive structures.
