What You Should Know
Tricholoma Saponaceum is an inedible mushroom found in woodlands in Europe and North America. This soapy smell fungus is so distinctive is a great help to fungus forayers, because the physical form and the colors of this woodland mushroom are very variable indeed. Cap usually tinged with olive; may be brownish on disc center. Gills close. Stalk thick; stains reddish when bruised.
In North American literature Tricholoma Saponaceum is generally treated as a medium-sized species with flesh that turns reddish to orangish in the base of the stem, a soap-like odor, and, well, pretty much any cap color you want and potential mycorrhizal association with any tree on earth.
Other names: Soap-Scented Toadstool, Soapy Knight, Soap Tricholoma, Tricholome À Odeur De Savon (France), Tricoloma De Olor A Jabón (Spain), Ziza Xaboisain (Euskara), Seifen-Ritterling (German).
Tricholoma saponaceums Mushroom Identification
Mycorrhizal with hardwoods or conifers; growing alone, gregariously, or in clusters; summer and fall (or in winter and spring in warmer areas); widely distributed in North America as a species group.
4–10 cm across; convex, becoming broadly convex or nearly flat, often with a central bump; dry; gray, copper-colored, or brownish; usually with a paler margin and a darker center; fairly bald, or with minute, appressed fibers.
Attached to the stem or notched; close; short-gills frequent; whitish; sometimes developing yellowish edges with age.
5–10 cm long; 1–2 cm thick; more or less equal; bald, or with silky appressed fibers, or with varying degrees of tiny grayish scales; dry; white to gray or yellowish; sometimes stained pinkish to orangish near the base; basal mycelium white.
Whitish and unchanging when sliced, except in the stem base, where it is usually pinkish to orangish (sometimes the color takes quite a while—even overnight—before manifesting).
Odor and Taste
Taste mealy or not distinctive; odor like soap, or mealy, or not distinctive.
Spores 4–9 x 3–6 µm; ellipsoid; smooth; hyaline in KOH; inamyloid. Lamellar trama parallel. Basidia 4-sterigmate, occasionally 2-sterigmate. Hymenial cystidia not found. Pileipellis a cutis; elements 3–6 µm wide, smooth, hyaline in KOH. Clamp connections present.
Tricholoma terreum is sometimes pale capped and then it can be quite similar to Tricholoma Saponaceum in appearance, but it does not have a distinctive soapy smell.
Tricholoma saponaceums Taxonomy and Etymology
Soap Knight mushroom was described scientifically by Christiaan Hendrik Persoon in 1801, its basionym dates from 1818 when the great Swedish mycologist Elias Magnus Fries gave it the name Agaricus saponaceus. Several varieties of the Soapy Knight are recognized, and the nominate form shown here is Tricholoma Saponaceum var. saponaceum.
Synonyms of Tricholoma Saponaceum var. saponaceum include Agaricus atrovirens Pers., Agaricus saponaceus Fr., Agaricus napipes Krombh., Tricholoma saponaceum (Fr.) P. Kumm., Tricholoma saponaceum var. atrovirens (Pers.) P. Karst., and Tricholoma saponaceum var. napipes (Krombh.) Barla.
Tricholoma Saponaceum var. squamosum (Cooke) Rea is a much rarer find in Britain and Ireland; it differs in having a very dark gray-brown cap (almost black in some instances) and dark scales also on the stem, but the soapy odor is just as obvious as in the nominate variety.
This variety of the Tricholoma saponaceums was described originally in 1884 by British mycologist Mordecai Cubitt Cooke, who gave it the name Agaricus saponaceus var. squamosus.
Tricholoma was established as a genus by the great Swedish mycologist Elias Magnus Fries. The generic name comes from Greek words meaning 'hairy fringe', and it must be one of the least appropriate mycological genus names because very few species within this genus have hairy or even shaggily scaly cap margins that would justify the descriptive term.
The specific epithet saponaceum comes from Latin and is a reference to the soapy smell that is given off when the gills are crushed.
Photo 1 - Author: Holger Krisp (Creative Commons Attribution 3.0 Unported)
Photo 2 - Author: Strobilomyces (Creative Commons Attribution-Share Alike 4.0 International)
Photo 3 - Author: Strobilomyces (Creative Commons Attribution-Share Alike 4.0 International)
Photo 4 - Author: Drew Parker (mycotrope) (Creative Commons Attribution-Share Alike 3.0 Unported)
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