| Amanita flavoconia | |
|---|---|
 | |
Scientific classification | |
| Kingdom: | Fungi |
| Division: | Basidiomycota |
| Class: | Agaricomycetes |
| Order: | Agaricales |
| Family: | Amanitaceae |
| Genus: | Amanita |
| Species: | A. flavoconia |
| Binomial name | |
| Amanita flavoconia | |
| Synonyms[2] | |
1941Amplariella flavoconia(G.F.Atk.)E.-J.Gilbert | |
| Amanita flavoconia | |
|---|---|
| Mycological characteristics | |
 | Gills onhymenium |
 | Cap is flat |
 | Hymenium is free |
 | Stipe has aring andvolva |
 | Spore print is white |
 | Ecology ismycorrhizal |
 | Edibility isunknown |
Amanita flavoconia, commonly known asyellow patches,yellow wart,orange amanita,yellow-dust amanita or theAmerican yellow dust amanita,[3] is a species ofmushroom in the familyAmanitaceae. It has an orangish-yellowcap with yellowish-orange patches or warts, a yellowish-orangeannulus, and a white to orange stem. Common and widespread throughout eastern North America, it grows on the ground inbroad-leaved andmixed forests, especially inmycorrhizal association withhemlock.
Amanita flavoconia was first described by American naturalistGeorge Francis Atkinson in 1902, based on a specimen he found in woods north of Fall Creek,Cayuga Lake Basin, New York State.[4]Jean-Edouard Gilbert placed it inAmplariella, in 1941,[5] while in 1948William Alphonso Murrill thought that it belonged best inVenenarius;[2][6] both of thesesegregate genera have been folded back intoAmanita.[7]
Thespecific epithetflavoconia meansyellowish andconical.[8] Itscommon names include "yellow patches",[8] "yellow wart",[9] "orange Amanita",[10] or "yellow-dust Amanita".[11]
Thecap is initiallyovoid in shape, but in maturity becomes convex and eventually flattened. Orange to bright yellow-orange in color, it reaches diameters of 3 to 9 centimetres (1 to3+1⁄2 inches).[8] Young specimens are covered withchrome yellow warts that may be easily rubbed off or washed away with rain.
The cap surface is smooth and sticky (viscid) beneath the warts; the edge of the cap isstriate, reflecting the arrangement of thegills underneath. Theflesh is white. The gills are barely free from the stem, and packed close together. They are white or tinged yellow on the edges, and initially covered with a yellowishpartial veil. Thestem is typically5.5 to 11.5 cm (2 to4+1⁄2 in) long by0.7 to 1.4 cm (1⁄4 to1⁄2 in) thick,[12] equal or slightly tapered upward from a small rounded bulb at the base. Its color may range from white to yellowish orange, and the surface may be smooth, or covered with small flakes. The base of the stem usually has chrome yellow flakes ofuniversal veil material adhering loosely to the bulb, or in the soil around the base. The partial veil leaves a skirt-like ring, (annulus) on the upper stem. Thespore print is white.[8]
Campbell and Petersen published a detailed description of the characteristics ofA. flavoconia grown in culture. In the era prior to the commonplace use of DNA analysis andphylogenetics, cultural characters were often used to help provide additionaltaxonomic information; they found considerable variability between different isolates.[13]
Two variants have been reported fromColombia, collected fromQuercus humboldtii forests:A. flavoconia var.sinapicolor and var.inquinata.[14]
Thespores are elliptical, smooth, and have dimensions of 7–9 by 5–8 μm. They arehyaline (translucent), andamyloid, meaning that they absorb the iodine stain inMelzer's reagent.[8] The spore-bearing cells, thebasidia, are up to 35–43 μm long by 4–12 μm, and each have foursterigmata, extensions that hold the spores.[15] The outer layer, or cuticle of the cap (known technically as thepileipellis) is made of filamentous interwoven gelatinizedhyphae, with diameters between 3 and 7 μm.[12]
This species has often been confused withA. muscaria, some subspecies of which are also orange-colored.[11] It also bears some resemblance toA. frostiana andA. flavorubescens. One 1982 study concluded that a "large majority" ofherbarium specimens labeled asA. frostiana were actuallyA. flavoconia. The use ofmicroscopic features is necessary to distinguish clearly among the species:A. flavoconia has elliptic, amyloid spores, whileA. frostiana has round, non-amyloid spores;A. muscaria has nonamyloid, elliptic spores. In the field,A. flavorubescens can usually be distinguished by its yellow cap color.[12]
A commonmycorrhizal mushroom,A. flavoconia grows solitarily or in groups on the ground in the summer to the fall, in broad-leaved and mixed woods. Noted for preferringhemlock, it is also associated with high elevationred spruce forests.[8]
In North America,A. flavoconia has a wide distribution and has been collected from several locations, including Ontario, Canada;[16] the United States[12] (Iowa),[17] and Mexico.[18][19] It has been described as "of the most common and widespread species ofAmanita in eastern North America."[20]
As the edibility of this species is unknown, it should not be consumed,[21] and a number of its relatives are quite poisonous.
Media related toAmanita flavoconia at Wikimedia Commons
