Tricholoma pardinum
Description
Tricholoma pardinum is a poisonous gilled mushroom widely distributed across North America, Europe, and parts of Asia. It is generally found in beech woodland in summer and autumn. Two subspecies have been described from southern Europe.
The fruit body of Tricholoma pardinum is an imposing mushroom with a pale grey cap up to 15 cm (6 in) in diameter that is covered with dark brownish to grayish scales. The gills are whitish and are not attached to the stout white to pale gray-brown stalk.
The European species appear under conifers. The overall appearance, mealy odor, and fairly large size make Tricholoma pardinum very similar to Tricholoma venenatum, which is a slightly paler, somewhat less scaly, hardwood-loving species, and to Tricholoma Smithii.
Tricholoma Tigrinum and Tricholoma Pardalotum are synonyms.
Common names: Spotted Tricholoma, Tiger Tricholoma, Tigertop, Leopard Knight, Dirty Trich.
Mushroom Identification
Ecology
Mycorrhizal with conifers in northern and montane areas, but associated with tanoak, madrone, and live oak on the West Coast; growing alone, scattered or gregariously; fall (winter on the West Coast); widely distributed in northern and montane North America, and on the West Coast.
Cap
4–15 cm; broadly convex, flat, or broadly bell-shaped; dry; grayish brown when unexpanded, but soon becoming whitish to pale grayish brown underneath small, regularly scattered, gray-brown to nearly black scales.
Gills
Attached to the stem by a notch; close; whitish to dull grayish; short-gills frequent.
Stem
3–12 cm long; 1–3.5 cm thick; equal or somewhat swollen below; covered with silky appressed fibers; dry; white; sometimes discoloring brownish where handled; basal mycelium white.
Flesh
Thick and firm; white to pale grayish; not changing when sliced.
Odor and Taste
Mealy.
Spore Print
White.
Chemical Reactions
KOH negative on cap surface.
Microscopic Features
Spores 7–9 x 4–5 µm; ellipsoid; smooth; hyaline in KOH; inamyloid. Basidia 4-sterigmate. Cheilocystidia, pleurocystidia not found. Pileipellis a cutis of cylindric elements 2.5–7.5 µm wide; hyaline to brownish in KOH. Clamp connections present.
Look-Alikes
Tricholoma pardinum mushrooms may be confused with several edible gray-capped members of the genus Tricholoma, and some authorities recommend leaving all gray-capped Tricholoma mushrooms for experienced hunters.
Several superficially similar European species could be mistaken for T. pardinum.
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The smaller and lacks a mealy smell and cap scales is darker and less robust and has smaller spores measuring 5.0–7.5 by 4.0–5.0 μm.
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The edible and somewhat resembles T. pardinum—but with finer scales, and gills and bruised parts that yellow with age. Unlike the preferentially montane T. pardinum, these lookalikes tend to fruit at lower elevations.
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Is smaller and darker than T. pardinum, and has a peppery aroma.
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Has fine dark scales and pinkish gills, brittle flesh, and is generally smaller.
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Is smaller than T. pardinum, has a thin, fibrous partial veil on young specimens, and elliptical spores measuring 5.0–6.0 by 3.5–4.0 μm. Edible and highly regarded.
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Has a similar size and uniform grey cap that is never scaled.
In North America, Tricholoma pardinum can be confused with T. nigrum and forms of T. virgatum that have more streaked rather than spotted caps. A form of T. pardinum in North America can be nearly white with pale scales, and may be confused with the whitish edible species T. resplendens. Microscopically, the presence of clamp connections sets T. pardinum apart from most other members of the genus; the similar-looking (though more tan-coloured) T. venenatum also has them. According to Alexander H. Smith, T. huronense is closely related, but can be distinguished from T. pardinum by its narrower gills, its tendency to form drops of reddish liquid on the gills and stalk, and an ash-gray and scaly stalk surface.
History
Tricholoma pardinum was described scientifically in 1801 by Christiaan Hendrik Persoon it is clear that others who recorded this species before him also have claims worthy of consideration. Jacob Christian Schaeffer was one such, as also was the Swiss mycologist Louis Gabriel Abraam Samuel Jean Secretan (1758 - 1839). Although Secretan was a lawyer he seems to have had little regard for the rules of botanical naming; as a result, names that he allocated are generally invalid unless they have been subsequently republished by other authors.
The widely accepted scientific name Tricholoma pardinum dates from an 1873 publication by the French mycologist Lucien Quélet.
Synonyms of Tricholoma pardinum include Agaricus myomyces var. pardinus Pers., Gyrophila tigrina Schaeff. ex Quél., and Tricholoma pardalotum Herink & Kotl.
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 pardinum comes from the Latin 'pardus' meaning leopard; it is a reference to the spotted nature of the cap of this mushroom.
Toxicity
Tricholoma pardinum is one of several poisonous members of the genus Tricholoma; its large size, fleshy appearance, and pleasant smell and taste add to the risk of its being accidentally consumed. It was responsible for more than twenty percent of cases of mushroom poisoning in Switzerland in the first half of the 20th century. Many cases of poisoning arise in the Jura Mountains.
Eating it causes highly unpleasant gastrointestinal symptoms of nausea, dizziness, vomiting, and diarrhea. These arise fifteen minutes to two hours after consumption and often persist for several hours; complete recovery usually takes four to six days.
Sweating and anxiety may be evident, and disturbance in liver function has been recorded. Cramping may occur in the calves. In one case, seven people and a cat suffered severe symptoms after sharing a meal that contained only two mushroom caps. The toxin, the identity of which is unknown, appears to cause a sudden inflammation of the mucous membranes lining the stomach and intestines.
These symptoms may be severe enough to warrant hospitalization. Treatment is supportive; antispasmodic medicines may lessen colicky abdominal cramps, and activated charcoal may be administered early on to bind residual toxin. Intravenous fluids may be required if dehydration has been extensive, especially with children and the elderly. Once gastric contents are emptied, metoclopramide may be used in cases of recurrent vomiting.
Photo sources:
Photo 1 - Author: 2012-03-28_Tricholoma_pardinum_Quél_208648.jpg: (CC BY-SA 3.0)
Photo 2 - Author: Ryane Snow (snowman) (CC BY-SA 3.0)
Photo 3 - Author: Jerzy Opioła (CC BY-SA 3.0)
Photo 4 - Author: Eric Steinert (CC BY-SA 2.5)
