Brown Roll-rim, Common Roll-rim, Poison Pax (Paxillus involutus)

Current name

Index Fungorum Paxillus involutus (Batsch) Fr.

MycoBank Paxillus involutus (Batsch) Fr.

Other names

Korovnik ("cow mushroom"), Matryoshka ("little Matryona" / nesting doll), Kobyłka ("little mare"), Dun'ka (diminutive of the female name Dunya), Svinukha ("little pig"), Korov'ya guba ("cow's lip"), Dunya, Dun'ka.

Systematic position

Specific epithet etymology

Involutus, a, um — rolled inward, coiled, spiral. Perfect passive participle of involvo, volvi, volutum, ere — to roll in, wrap up, enfold, cover, envelop.

Synonyms

Agaricus adscendibus Bolton [as 'adscendentibus'], Hist. fung. Halifax (Huddersfield) 2: 55 (1788)

Agaricus contiguus Bull., Herb. Fr. (Paris) 5: pl. 240 (1785)

Agaricus contiguus Bull., Hist. Champ. Fr. (Paris) 2(1): 518 (1792)

Agaricus involutus Batsch, Elench. fung. (Halle): 39 (1783)

Agaricus involutus var. stillans Pers., Mycol. eur. (Erlanga) 3: 63 (1828)

Agaricus involutus var. terrestris Alb. & Schwein., Consp. fung. (Leipzig): 216 (1805)

Agaricus involutus var. truncigenus Alb. & Schwein., Consp. fung. (Leipzig): 216 (1805)

Agaricus involutus ß truncigenus Pers., Syn. meth. fung. (Göttingen) 2: 448 (1801)

Omphalia involuta (Batsch) Gray, Nat. Arr. Brit. Pl. (London) 1: 611 (1821)

Omphalia involuta var. truncigena (Pers.) Gray, Nat. Arr. Brit. Pl. (London) 1: 611 (1821)

Paxillus involutus f. eburneus Gelardi, Segneri & Vizzini, in Gelardi, Segneri, Ercole & Vizzini, Mycosphere 2(5): 548 (2011)

Paxillus involutus f. subrubicundulus Bon, in Bon & Van Haluwyn, Docums Mycol. 11(no. 44): 32 (1981)

Paxillus involutus var. leptopus (Fr.) Quél., Enchir. fung. (Paris): 93 (1886)

Paxillus involutus var. simplex Peck, Ann. Rep. Reg. N.Y. St. Mus. 53: 857 (1901) [1900]

Paxillus leptopus Fr., Monogr. Hymenomyc. Suec. (Upsaliae) 2(2): 311 (1857)

Rhymovis involuta (Batsch) Rabenh., Deutschl. Krypt.-Fl. (Leipzig) 1: 453 (1844)

Habit

Fruiting body

Agaricoid (cap and stipe)

Hymenophore

Lamellate (gills present, including folded or rudimentary)

Fruiting period (list)

JunJune (1st–10th)June (11th–20th)June (21st–30th)JulJuly (1st–10th)July (11th–20th)July (21st–31st)AugAugust (1st–10th)August (11th–20th)August (21st–31st)SepSeptember (1st–10th)September (11th–20th)September (21st–30th)OctOctober (1st–10th)October (11th–20th)October (21st–31st)

Mushroom cap

Cap 3–12 cm in diameter, sometimes larger, fleshy; initially convex with an inrolled margin, later becoming flat with a depressed center and a straight or upturned edge, rarely funnel-shaped. The cap surface is smooth, rarely with small bumps, finely pubescent. The margin is pubescent. In young specimens, the cap is light olive with brownish tones, later becoming brown, dark brown, with a rusty or reddish-brown hue. The cap surface is dry, becoming sticky in wet weather. The hymenophore is decurrent and folded; it is sometimes described as gilled, but this is only a visual resemblance. The folds run down the stipe. The folds are yellowish or olive-colored and often forked. With age, they acquire a brick-reddish tint.

Stem

3–10 cm long, 1–3 cm in diameter, solid, sometimes curved, central or slightly eccentric. Lighter in color than the cap. Brownish-yellow in the upper part, becoming dark brown toward the base. Smooth.

Flesh

Yellowish, loose, darkening when broken. Odor strong, mushroom-like, sometimes with slight fruity notes.

Microscopy

Spore print brown. Spores ellipsoid, smooth.

Ecology and distribution

Grows in groups, on soil in mixed and deciduous forests. Forms mycorrhiza with many tree species, for example Betula, Populus tremula and Pinus sylvestris. Shows a preference for anthropogenically disturbed and ruderal habitats. Can exhibit substrate lability and colonize decaying wood.

Fruiting

June–October.

Nutritional properties

Poisonous

A deadly poisonous mushroom, especially when consumed repeatedly. The substances contained in the Brown Roll-rim have a cumulative effect. Poisoning by this mushroom is known in medicine as "paxillus syndrome." Depending on the amount of mushrooms consumed and the individual's health condition, poisoning can range from mild—abdominal pain and diarrhea—to severe: damage to blood erythrocytes, development of hemolysis and hemolytic anemia. No antidote exists.

Similar species

It has no true look-alikes, but is difficult to distinguish from other species of Paxillus: the Copper Roll-rim (Paxillus cuprinus), the Dark-spored Roll-rim (Paxillus obscurisporus), and the Alder Roll-rim (Paxillus filamentosus).

Notes

Paxillus involutus is a species complex that cannot be distinguished under field conditions. Laboratory crossing experiments and molecular studies are used to determine species affiliation.

Related resources

Jargeat P., Chauneton J-P., Navaud O., Vizzini A., Gryta B. The Paxillus involutus (Boletales, Paxillaceae) complex in Europe: Genetic diversity and morphological description of the new species Paxillus cuprinus, typification of P. involutus s.s., and synthesis of species boundaries. // Fungal Biology. — 2014. — Vol. 118. — P. 12–31.

Breitenbach J, Kränzlin F. Fungi of Switzerland. A contribution to the knowledge of the fungal flora of Switzerland. Vol 3. Boletes and agarics. 1st part. Strobilomycetaceae and Boletaceae, Paxillaceae, Gomphidiaceae, Hygrophoraceae, Tricholomataceae, Polyporaceae (lamellate). — Lucerne: Verlag Mykologia, 1991. — 360 p. — P. 92.

Straus A. Mushroom poisonings in 1946 in Berlin and Brandenburg. // Zeitschrift für Pilzkunde. — 1949. — Vol. 21. — P. 37–41.

Gry J., Andersson C. Mushrooms traded as food. Vol II sec. 2. Nordic Risk assessments and background on edible mushrooms, suitable for commercial marketing and background lists. For industry, trade and food inspection. Risk assessments of mushrooms on the four guidance lists. — Nordic Council of Ministers, 2014. — P. 314.

Sanitary Rules for the Harvesting, Processing and Sale of Mushrooms (No. 2408-81), approved by the Deputy Chief State Sanitary Physician of the USSR A. I. Zaichenko, 30.06.1981.

Sanitary Rules for the Harvesting, Processing and Sale of Mushrooms (SP 2.3.4.009-93), approved by the Resolution of the State Committee for Sanitary and Epidemiological Supervision of Russia dated 20.08.1993, No. 10.

Medical Toxicology: National Guidelines / Ed. by E. A. Luzhnikov. — Moscow: GEOTAR-Media, 2012. — 928 p. — P. 752.

Pohle W. Paxillus involutus — a dangerous mushroom? // Czech Mycology. — 1995. — Vol. 48 (1). — P. 31–38.

Henrici A., Kibby G. Paxillus — an end to confusion? // Field Mycology. — 2014. — Vol. 15 (4). — P. 121–127. DOI: 10.1016/j.fldmyc.2014.09.007.

Hedh J., Samson P., Erland S., Tunlid A. Multiple gene genealogies and species recognition in the ectomycorrhizal fungus Paxillus involutus. // Mycological Research. — 2008. — Vol. 112. — P. 965–975.

Link to this page for printed editions

Shipovalov A.G. Brown Roll-rim, Common Roll-rim, Poison Pax (Paxillus involutus) - Mushrooms of Vologda Region [Electronic resource] URL: https://xn----7sbancweblffgklubds60aja.xn--p1ai/en/brown-roll-rim-common-roll-rim-poison-pax-paxillus-involutus (accessed: 13.04.2026).