E-Flora BC: Electronic Atlas of the Flora of British Columbia

Agaricus micromegethus Peck
anise Agaricus
Agaricaceae

Species account author: Ian Gibson.
Extracted from Matchmaker: Mushrooms of the Pacific Northwest.

Introduction to the Macrofungi

© Michael Beug  Email the photographer   (Photo ID #15220)

E-Flora BC Static Map
Distribution of Agaricus micromegethus
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Species Information

Summary:
features include small size, whitish cap with fibrils or fibrillose scales that are pinkish or yellowish brown at first and become brownish to grayish brown, tendency of cap and stem to become deep yellow, fragile flesh, slight fragile skirt-like ring, anise or almond odor, growth in grass, and small spores; also known as Agaricus megathus; Murrill give distribution New England (including VA, NJ) to TN, west to MI and TX, Hotson and Isaacs for WA, Phillips for OR, Kerrigan for CA; collections from BC deposited at University of British Columbia, CHEMICAL REACTIONS staining bright yellow in 3-15% KOH (Chariton), cap surface staining yellow in KOH (Arora)
Cap:
2-4cm across, "broadly convex to convex-truncate when young, becoming depressed centrally", when old nearly flat; dry, innately fibrillose, fibrils pinkish red, darkening to gray-brown or more dingy, forming appressed to slightly repent fine scales about 0.2cm long and 0.1-0.2cm wide, background whitish to buff, (Kerrigan), 4.5cm across approximately, convex, not umbonate; center brown, elsewhere pallid or whitish, staining deep yellow where bruised; innately fibrillose or with few minute appressed scales, (Hotson), 2-5(8)cm across, convex to flat; dry, "with silky fibrils or fibrillose scales (sometimes very sparse toward the margin)", "fibrils at first pinkish in one form, yellow-brown in another, but in both forms becoming brownish to grayish-brown in age on a whitish to buff background", "yellow to orange stains often developing in age or upon handling", (Arora), "fibrils pinkish-red, in age darkening to gray-brown or darker brown" and "streaked with tiny vinaceous-brown scales; surface bruises saffron yellow to ochraceous", (Chariton), cap exceeding gills markedly, 0.1-0.2cm, (Isaacs)
Flesh:
up to 0.4cm thick; white, unchanging or becoming yellowish, in stem white, to salmon orange when old, (Kerrigan), thick, white, unchanging, (but also notes all parts of sporophore staining deep saffron-yellow where bruised), (Hotson), thin, fragile; "white, unchanging or bruising yellowish", (Arora)
Gills:
free, close, up to 0.3cm broad, "greyish when young, soon pinkish" (quoted from Peck), finally dark blackish brown, (Kerrigan), crowded, broad, thin; white for a long time, becoming pink then purplish gray, (Hotson), free at maturity, close; "pallid or grayish, then pinkish, finally chocolate-brown or darker", (Arora), finally chocolate brown or red-brown, (Chariton)
Stem:
2.5-3cm x 0.2-0.8cm, equal or very slightly bulbous, narrowly stuffed-hollow, cavity 0.05-0.1cm broad; white, becoming orangish when old or when bruised; finely fibrillose when young, bald when old, (Kerrigan), about 4cm long and 0.8cm wide, short, stout, solid; white, staining deep yellow where bruised; bald, (Hotson), 2-6cm x 0.3-1cm, equal or slightly widened at base, "stuffed or hollow, fragile at maturity"; white or staining yellow to orange upon handling, especially in lower part, (Arora)
Veil:
veils sometimes appendiculate, more usually forming a pendant (to intermediate-type), subapical to supramedian white ring, flaring 0.2-0.4cm, partial veil white, loosely interwoven, universal veil a narrow denser zone on ring undersurface, soon becoming orangish, also leaving deciduous fibrils on stem, (Kerrigan), ring "median or inferior, narrow, thin, simple, persistent, white", (Hotson), membranous, thin, "forming a fragile, superior to median ring" or disappearing, ring skirt-like or intermediate, (Arora)
Odor:
almond (Kerrigan), distinctly sweet (anise-like or almondy), (Arora), pleasant (Phillips), pleasant, faintly of anise, (Kibby)
Taste:
pleasant (Phillips), nutty - almond-like (Isaacs)
Microscopic spores:
spores (3.8)4.6-4.9(5.6) x (3.0)3.5-3.8(4.1) microns, elliptic to broadly elliptic, dark brown, hilar appendix fairly prominent, germ pore not evident; basidia 4-spored, 21-25 x 5-7 microns, cylindroclavate, sterigmata 2-3 microns long; cheilocystidia not observed, gill margin fertile, (Kerrigan), spores 5-6 x 4-4.5 microns, (Hotson), spores 4.5-5.5 x 3.5-4 microns, broadly elliptic, smooth, (Arora)
Spore deposit:
chocolate brown (Arora)

Habitat / Range

gregarious in lawns, pastures and grassy places, (Kerrigan), single to scattered or gregarious "in lawns, pastures, fields and other grassy or open places", (Arora), prefers short turf especially sandy soils (Kibby)

Taxonomic and Nomenclatural Links


Genetic information (NCBI Taxonomy Database)
Taxonomic Information from the Missouri Botanical Garden
Index Fungorium
Taxonomic reference: Kerrigan(1) (as A. micromegathus), Hotson(1), Arora(1) (as Agaricus micromegathus), Phillips(1)*, Kibby(1)* (as Agaricus micromegathus), Chariton(1) (as A. micromegathus), Isaacs(1), Murrill(7), Dilly(1)

Additional Range and Status Information Links

Edibility

yes (Arora)

Additional Photo Sources

Related Databases

Species References

Kerrigan(1) (as A. micromegathus), Hotson(1), Arora(1) (as Agaricus micromegathus), Phillips(1)*, Kibby(1)* (as Agaricus micromegathus), Chariton(1) (as A. micromegathus), Isaacs(1), Murrill(7), Dilly(1)

References for the fungi

General References