False Chanterelle

''Hygrophoropsis aurantiaca'', commonly known as the false chanterelle, is a species of fungus in the family Hygrophoropsidaceae.

Austrian naturalist Franz Xaver von Wulfen described the false chanterelle in 1781, noting both its resemblance with the true chanterelles and people's propensity to confuse them. The false chanterelle was then placed in the genus ''Clitocybe'', but it was later observed that its forked gills and dextrinoid spores indicated a relationship to ''Paxillus''. Genetic analysis has confirmed that it belongs to the order Boletales and is more closely related to boletes.

The fruit bodies (mushrooms) are yellow–orange, with a funnel-shaped cap up to across that has a felt-like surface. The thin, often forked gills on the underside of the cap run partway down the length of the otherwise smooth stipe. The species is found across several continents, growing in woodland and heathland, and sometimes on woodchips used in gardening and landscaping. Reports on the mushroom's edibility vary; it is considered poisonous, but has historically been eaten in parts of Europe and the Americas.

Taxonomy

Austrian naturalist Franz Xaver von Wulfen described the false chanterelle as ''Agaricus aurantiacus'' in 1781, reporting that it appeared in the fir tree forests around Klagenfurt in October. He added that it could be confused with the chanterelle by the inexperienced, but that its true nature was very different; in contrast to its edible lookalike, he described it as "kind of pernicious". The specific epithet is the Latin word ''aurantiacus'', meaning "orange". James Sowerby illustrated it and gave it the name ''Agaricus subcantharellus'', describing it as a "perhaps unfavourable" variety of ''A. cantharellus'' (chanterelle). The fungus was placed in the genus ''Merulius'' by Johann Friedrich Gmelin in 1792, and then ''Cantharellus'' by Elias Fries in 1821. Bernhard Studer-Steinhäuslin concluded it could only be classified in the genus ''Clitocybe'' in 1900, based on its white spores, decurrent gills and lack of a ring. It was elevated to the status of genus in a 1929 publication by Emile Martin-Sans, with authorship attributed to René Maire. Martin-Sans concurred with Maire's assessment of ''Hygrophoropsis'', suggesting that it represented a form intermediate between ''Cantharellus'' and ''Clitocybe'', and was thus worthy of generic ranking. The genus name refers to a resemblance to the genus ''Hygrophorus''. It is commonly known as the false chanterelle.

Two varieties described by Derek Reid in 1972, ''H. aurantiaca'' var. ''macrospora'' and ''H. aurantiaca'' var. ''rufa'', have since been promoted to distinct species status as '' H. macrospora'' (1996) and '' H. rufa'' (2008). Two other varieties of the fungus have been described, but they are not considered to have independent taxonomic significance by Index Fungorum: var. ''nana'' (Singer 1946), characterized by a small fruit body; and var. ''robusta'' (Antonín 2000), characterized by a robust fruit body and an odour similar to Maggi seasoning sauce. Pale forms of the fungus are sometimes referred to as var. ''pallida''. This taxon was first published by Robert Kühner and Henri Romagnesi in 1953, but later considered validly published name, invalid as it did not conform to International Code of Nomenclature for algae, fungi, and plants, nomenclatural rules. Variety ''nigripes'', a taxon with a black-brown Stipe (mycology), stipe, is invalid for similar reasons. ''H. aurantiaca'' var. ''pallida'' was published validly in 1995.

In 1979, Egon Horak suggested that ''H. aurantiaca'' and the New Zealand taxon ''Hygrophoropsis coacta, H. coacta'' were the same species, but neither Index Fungorum nor MycoBank accept this synonymy. According to MycoBank, ''H. aurantiaca'' has several heterotypic synonyms, i.e. different type (biology), types but considered the same species:
* ''Agaricus alectorolophoides'' Jacob Christian Schäffer, Schaeff. (1774)
* ''Agaricus subcantharellus'' James Sowerby, Sowerby (1809)
* ''Cantharellus brachypodus'' François Fulgis Chevallier, Chevall. (1826)
* ''Cantharellus ravenelii'' Miles Joseph Berkeley, Berk. & Moses Ashley Curtis, M.A.Curtis (1853)
* ''Merulius brachypodes'' (Chevall.) Otto Kuntze, Kuntze (1891)

''Hygrophoropsis aurantiaca'' has been confused with the true chanterelles (genus ''Cantharellus'') because of overall similarities in appearance. However, the forked gills, frequently off-centre stipe placement, and dextrinoid spores of ''H. aurantiaca'' suggested a relationship with ''Paxillus'', prompting Rolf Singer to classify the genus ''Hygrophoropsis'' in the family Paxillaceae in 1946. Several biological pigment, pigments have been identified from the fungus, including the orange variegatic acid, methyl variegate, the red variegatorubin, and several derivative (chemistry), derivatives of pulvinic acid. The presence of these pigments suggests a chemotaxonomy, chemotaxic relationship with the Boletaceae, Coniophoraceae, and Paxillaceae – families of Boletales with members that have similar compounds. Molecular phylogenetic analysis confirmed its affinity lay in the order Boletales in 1997, though later research showed it is not closely related to ''Paxillus'' or other gilled members of the order.

Description

The species has a golden-orange cap ranging from in diameter, initially convex but becoming funnel-shaped as the mushroom matures. The cap margin, which remains rolled in a little, becomes wavy or lobed in age. The cap surface is covered with a fine down. The decurrent gill-like structures are narrow and forked, which is a distinctive and distinguishing feature. They are generally a more intense shade of orange than the cap. Along the stipe, the gills may be slightly crimped. The orange stipe is tall and thick, and lacks a ring. It often has a darker, brownish, base. The ability to form sclerotia (compact masses of hardened fungal mycelium) has been documented for ''H. aurantiaca'' in laboratory studies. These structures contain glycogen and protein that may be used as food reserves during spore germination.

The soft, thin trama (mycology), flesh ranges from white to yellowish to golden-orange. It has an odour and taste described variously as indistinct, or unpleasant and earthy. The spore print is white to cream (colour), cream. The oval basidiospore, spores are 5.5–7 by 4–4.5 micrometres (μm), with walls that tend to thicken in age. The spores are cyanophilous, meaning they will readily staining, stain dark blue in methyl blue solution. Staining with Melzer's reagent often produces a dextrinoid (reddish-brown) colour reaction. Basidia (spore-bearing cells) measure 25–40 by 5–8 μm, and can be two-, three-, or four-spored. Cystidia (large sterile cells on the hymenium) are absent. The cap cuticle is in the form of a trichoderm, where the outermost hyphae are roughly parallel, like hairs, perpendicular to the cap surface. These hyphae are 4–15 μm in diameter, and contain intracellular pigments that impart an orange-brown to yellow-brown colouring to the cells. Clamp connections are present in the hyphae.

Teratology, Teratological (developmentally abnormal) forms of ''H. aurantiaca'' have been reported to occur in the United Kingdom. The fruit bodies of these specimens were club-shaped with a wrinkled upper surface of convoluted gill tissue. The overall morphology (biology), morphology of these forms somewhat resembles species of ''Clavariadelphus''. Although the cause of this abnormal development is not known with certainty, environmental pollutants or mycovirus, virus infection have been suggested as contributing factors.

Similar species

Characteristics typically used in the field to distinguish ''Hygrophoropsis aurantiaca'' from lookalike species include: the soft, dry consistency of its cap; the crowded, decurrent, and forked gills that are saffron (color), saffron to orange coloured; and the lack of any distinctive taste or odour. The false chanterelle can be distinguished from the true chanterelle (''Cantharellus cibarius'') by its deeper orange colour, brown base to the stipe, velvety cap surface, forked gills rather than gill-like ridges, softer (and thinner) flesh, and lack of the characteristic apricot-smell. The cap surface of ''Hygrophoropsis fuscosquamula'', found in Britain, has fine brown scales overlaying a dull orange background. ''H. rufa'' has velvety brown fur covering its cap, while ''H. macrospora'' has cream gills and stipe. Microscopically, these three species have larger spores than ''H. aurantiaca''. ''Hygrophoropsis tapinia, H. tapinia'', found in a range extending from southern Florida to Central America, is set apart from ''H. aurantiaca'' by its growth on or under deciduous trees (never conifers), and smaller spores, which measure 3.3–4.8 by 2.5–3.3 μm.

Formerly a member of ''Hygrophoropsis'', ''Aphroditeola olida'' is also similar in appearance to ''H. aurantiaca'' but can be distinguished from the false chanterelle by its smaller, pinkish fruit bodies and candy-like odour. It also has smaller spores. ''Chrysomphalina chrysophylla'' has a yellowish brown cap and unforked yellow gills. ''Cortinarius hesleri'', an eastern North American species that associates with oaks, has a rusty brown spore print and a partial veil, cortina in young specimens. The poisonous Omphalotus, jack-o'-lantern mushrooms (genus ''Omphalotus'') comprise another group of lookalikes; however, they have straight, non-forked true gills. The European wood-rotting species ''Haasiella splendidissima'', sometimes confused with ''H. aurantiaca'', is most readily distinguished from the latter by its pink spore print and gills that do not fork. Additionally, species of ''Infundibulicybe'' and ''Paralepista'' have unforked cream-to-tan gills.

Distribution and habitat

''Hygrophoropsis aurantiaca'' is a widely distributed species. In Europe and North America, it is found in both hardwood and conifer forests, as well as heathland, in summer and autumn. In North America, it can be found from July–October to the east and September–January on the West Coast. It can be found in Central and South America, and Mexico, where it is common in coniferous forests. It has also been recorded in northern Asia, Australia and New Zealand. Populations in California represent a species complex, complex of undescribed species that are collectively referred to as ''Hygrophoropsis aurantiaca'' ''sensu lato''.

It fruits from the ground or from decaying wood, on burned areas in forests, and is often found near fallen trees and tree stumps. The fungus can also grow on woodchips used in gardening and landscaping, and so it also appears on roadsides and other locations where this material is used. Fruit bodies occur singly to scattered, or in clusters, and can be very abundant. Generally considered a dry weather mushroom, it can be plentiful when other mushrooms are scarce.

Ecology

A saprophytic fungus, ''H. aurantiaca'' obtains nutrients from forest litter and decomposing wood, causing a Wood-decay fungus#Brown rot, brown rot on the wood upon which it grows.

''H. aurantiaca'' secretes large amounts of oxalic acid, a reducing agent and relatively strong acid. This stimulates weathering of the humus layer of forest soil, and influences the solubility and turnover of nutrients (particularly phosphorus and nitrogen), which in turn affects their availability for use by forest trees.

Edibility

The false chanterelle is considered poisonous and may cause serious digestive problems. Among other toxins, it contains high levels of the sugar alcohol arabitol. The mushroom was sometimes described as edible mushroom, edible (though not tasty) until 1999. Fries described it as ''venenatus'', meaning "poisonous", in 1821. Considering the species potentially edible, David Arora speculated that it may have been confused with similar-looking but definitely poisonous species of ''Omphalotus''. Italian mycologist Nicola Sitta has reported that the one attributed case of poisoning he knew of could be attributed to an idiosyncratic reaction as only one of three people eating it got symptoms and concludes that it is harmless. It is eaten in Spain and France, and can legally be sold in France and Belgium. It is not recommended in Italy due to its similarity to poisonous species. It is eaten, though not highly regarded, by the Zapotec people of Ixtlán de Juárez in Oaxaca. The Tepehuán people of northwestern Mexico also occasionally eat the mushroom, which they refer to in their Tepehuán language, native language as ''guin'xacan'' ("delightful") or ''kia's gio ("iguana lard"); there, it is commonly prepared by roasting over charcoal, or boiling and garnishing with cheese.

Notes

References

External links

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{{Taxonbar, from=Q1265541

Hygrophoropsidaceae
Fungi described in 1781
Fungi of Asia
Fungi of Australia
Fungi of Central America
Fungi of Europe
Fungi of New Zealand
Fungi of North America
Fungi of South America
Taxa named by Franz Xaver von Wulfen
Fungus species
Poisonous fungi