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Summary: Features include very convoluted, yellow brown to red brown cap, slightly grooved stem that is whitish to cap-colored, and fruiting in spring. Despite its name, Gyromitra esculenta can be very poisonous when eaten raw, although toxicity varies with the individual, and certain individuals who have eaten Gyromitra mushrooms without effect have had severe reactions on another exposure. In a 1967 report of 513 cases of this kind of poisoning, 14% were fatal. Gyromitra esculenta contains hydrazones such as gyromitrin with chemical name N-methyl-N-formylhydrazone acetaldehyde, which is metabolized to what appear to be the major toxin, monomethylhydrazine (that has been used as a rocket fuel). Much but not all of this becomes a vapor during cooking and can be poisonous as vapor. Poisoning starts between 2 and 24 hours and may start with vomiting, diarrhea, abdominal pain and headache. Sometimes there is fever. Liver toxicity occurs about 36-48 hours, and then neurological symptoms including seizures and coma. Sometimes there is intravascular hemolysis, kidney failure, or methemoglobinemia. With lower doses, there is still concern that these mushrooms are carcinogenic. (Benjamin, from "Despite"). Collections of Gyromitra esculenta were examined from BC, WA, OR, ID, and also AB, MB, ON, PQ, YT, AK, WY, Belgium, Czechoslovakia, United Kingdom, Norway, and Sweden (Abbott). It is also reported from Asia (Abbott).
Cap: 2-10cm, rounded or sometimes more or less flat or saddle-shaped, irregularly three- to five-lobed; sometimes yellowish to yellowish brown, more commonly light to dark reddish brown and becoming darker on drying; sometimes nearly smooth, but typically strongly wrinkled to folded into many convolutions and appearing more or less brain-like, (Ammirati(11)), 0.5-9cm across, 0.5-5.5cm high, up to 14 x 11cm when fresh, irregularly lobed, highly convoluted, margin reflexed, fused to stem in several locations, rarely free when young; medium to dark red brown, sometimes orange brown or with paler red to orange brown regions, dark red brown to blackish red brown when dry, (Abbott), "varies from dull red to rusty red, reddish brown, or darker brown, sometimes with yellow or orange tints", when old often black, (Trudell)
Flesh: rather thin and brittle, (Arora), whitish to pallid (Ammirati(11))
Underside: paler than outer surface of cap, (Arora), white to pale yellow brown or pale red brown, finely pubescent, (Abbott)
Stem: 2-15cm x 1-2.5cm, often widening downward and enlarged at base, more or less round in cross-section, often longitudinally grooved, hollow, typically with a single channel; white to pale brown or tinted the color of the cap, (Ammirati(11)), 0.5-9cm x 0.3-3cm, 4in long and 7cm wide fresh, equal, enlarged at base, or tapered to base, slightly to strongly fluted at base or along entire stem, often round in cross-section when young, solid or with hollow chambers; cream, yellow brown, or red brown, typically with strong purple tints; pubescent (with finely hairs), (Abbott), tinted with cap color "but often also with pinkish or grayish purple tones near the base", (Trudell), stuffed or hollow (or with two narrow hollows) in cross-section, smooth or grooved vertically but not ribbed, (Arora)
Odor: mild (Ammirati(11))
Taste: mild (Ammirati(11))
Microscopic: spores 16.7-23.4 x 7.3-9.4 microns, elliptic, smooth, 8 spores per ascus, (Ammirati(11)), spores (17)19.1-28 x 10-13.1(14) microns, elliptic to subfusoid (somewhat spindle-shaped), smooth, with 2 droplets, apiculus absent or apices slightly thickened to 1 micron; asci 180-220 x 15-17 microns; paraphyses 2-9(10) microns diameter at apex, clavate, gradually enlarging or abruptly swollen, pale brown, brown in mass, contents granular, apical cell 39-77 microns long, (Abbott)
Spore Deposit: white to ochraceous (Abbott)
Habitat / Range
single, gregarious, subcespitose [somewhat tufted], or scattered on ground in soil, litter, woody debris, occasionally on well-rotted wood or burnt debris, under conifers or in mixed woods, in spring, (Abbott), typically found with conifers, especially pine, but has also been reported with aspen, (Ammirati(11)), March to May, (Phillips), on ground in disturbed or undisturbed mixed conifer and hardwood forests and occasionally in urban lawns, (Castellano), "associated with conifers and hardwoods and may be found on soil or rotten wood"; spring or early summer, (Trudell)
Gyromitra infula and Gyromitra ambigua are somewhat similar but G. esculenta is more convoluted, fruits in spring and differs microscopically. Gyromitra montana has an irregular hollow stem with several internal anastomosing channels, whereas the hollow stem of Gyromitra esculenta is more or less round in cross-section, typically with one internal channel, or sometimes somewhat flattened with two internal channels.
Recommended citation: Author, Date. Page title. In Klinkenberg, Brian. (Editor) 2019. E-Flora BC:
Electronic Atlas of the Plants of British Columbia [eflora.bc.ca]. Lab for
Advanced Spatial Analysis, Department of Geography, University of British
Columbia, Vancouver. [Accessed:
2020-02-20 8:26:27 PM
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