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Chlorophyllum rhacodes

[ Basidiomycota > Agaricales > Agaricaceae > Chlorophyllum . . . ]

by Michael Kuo

Sometimes called the "shaggy parasol," Chlorophyllum rhacodes is an impressive mushroom, characterized by its large size, its shaggy and scaly cap, its white spore print, and the way its flesh turns pinkish orange when sliced (especially at the apex of the stem). In western North America it should be compared with the very similar Chlorophyllum brunneum, which has a rimmed basal bulb, consistently truncated spores, and longer, narrower cheilocystidia. (Actually, Chlorophyllum brunneum appears in eastern North America, too, but it is very rare there.) The widely distributed Chlorophyllum molybdites is easily separated on the basis of its greenish mature gills and spore print.

Synonyms include Lepiota rhacodes and Macrolepiota rhacodes--and Lepiota/Macrolepiota/Chlorophyllum rachodes--with a CH instead of an RH. This spelling is an error that originated with the 19th-Century author of the species, Vittadini (1835), who misspelled (or, better put, mis-transliterated) ρακωδης, the Greek word for "ragged" or "tattered"--an apt description of the mushroom. Vellinga and Pennycook (2010) argue that Vittadini might also have meant "ραχωδης," the Greek word for "bush," because he might have found it under an old, half-dead bush (he wrote, "sotto un antico e semimorto cespite de nocciuolo"). I find this argument entirely unconvincing. "Hey, here's a new species with a ragged cap. I'm going to write the word 'ragged' in my description of the cap, because it's so, well, ragged. Hmm . . . I wonder what should I call it? How about 'the bush Lepiota?'" No. Vittadini's "rachodes" is clearly a misspelling, and according to Article 60.1 of the International Code of Nomenclature, it is allowable to correct his mistake.

Description:

Ecology: Saprobic; growing alone, scattered, or gregariously--often in troops or fairy rings--in lawns and disturbed-ground areas like roadsides, gardens, the edges of fields, and so on; often appearing in the vicinity of conifers (especially spruces); spring through fall; widely distributed in North America, but more common from the Rocky Mountains eastward. The illustrated and described collections are from Illinois.

Cap: 9-16 cm; convex to nearly round when young, becoming broadly convex, flat, or very broadly bell-shaped; dry; soft; bald and grayish brown when in the button stage, but soon breaking up so that the center remains smooth (or cracked) and brown but the rest of the surface consists of shaggy scales with brownish tips over a whitish, fibrillose background.

Gills: Free from the stem; close or nearly crowded; short-gills frequent; white or, in maturity, pale brownish; often with brownish edges.

Stem: 10-21 cm long; 2-3.5 cm thick; club-shaped, with a basal bulb that is gradually swollen; bald; whitish above the ring, brownish below; bruising and discoloring brown to brownish; with a high, double-edged, moveable ring that features a brownish edge on the underside.

Flesh: Whitish to pale brownish; staining pinkish orange to reddish, then slowly brownish when sliced (especially near the apex of the stem); thick.

Odor and Taste: Not distinctive.

Chemical Reactions: KOH negative or pinkish on cap surface (brown areas).

Spore Print: White.

Microscopic Features: Spores 10-14 x 5-8 µ; ellipsoid, subamygdaliform, or ellipsoid with a truncated end; smooth; hyaline in KOH; dextrinoid. Cheilocystidia 15-30 x 12.5-18 µ; widely clavate to subsphaeropedunculate; hyaline in KOH; thin-walled. Pleurocystidia absent. Pileipellis a trichoderm (center of cap, or scales) or cutis (whitish, fibrillose surface).

REFERENCES: (Vittadini, 1835) Vellinga, 2002. (Saccardo, 1887; Morgan, 1907; Kauffman, 1924; Smith, 1949; H. V. Smith, 1954; Smith, 1975; Smith, Smith & Weber, 1979; Arora, 1986; Phillips, 1991/2005; Lincoff, 1992; Barron, 1999; Vellinga, 2003a; Vellinga, 2003c; McNeil, 2006; Miller & Miller, 2006; Kuo, 2007; Vellinga, 2007c; Lange, 2008; Vellinga, 2008b; Trudell & Ammirati, 2009; Vellinga & Pennycook, 2010; Kuo & Methven, 2014; Evenson, 2015.) Herb. Kuo 09290504, 0514110.


Further Online Information:

Macrolepiota rhacodes at Roger's Mushrooms

 

Chlorophyllum rhacodes

Chlorophyllum rhacodes

Chlorophyllum rhacodes

Chlorophyllum rhacodes

Chlorophyllum rhacodes
Spores

Chlorophyllum rhacodes
Cheilocystidia



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Kuo, M. (2015, July). Chlorophyllum rhacodes. Retrieved from the MushroomExpert.Com Web site: http://www.mushroomexpert.com/chlorophyllum_rhacodes.html