Tricholoma portentosum

Description

Tricholoma portentosum can be distinguished by a dark grey to gray-brown, streaked viscid cap with conspicuous radiating fibrils, a faintly farinaceous odor, and taste, growth with conifers, and a cap, gills, and stipe that develop yellow tones at maturity. It is found in woodlands in Europe and North America.

Common names: Charbonnier, Sooty Head.

Mushroom Identification

1. Cap

   5-8 (12) cm, initially conical-campanulate, then convex and finally flat, corrugated, wide and obtuse umbo; curved (non-inrolled) margin, then extended, lobed, fissured, with the age it can be even revolute. The cuticle is partially separable, with radial fibrils, sticky and glossy when the weather is humid, sericious and bright when the same is dry, the color is variable, steel grey, ochre grey, blackish grey, slate grey.

2. Hymenium

   Trimmed on the margin gills, little thick, wide, and sinuous, intercalated by several lamellulas, the thread is irregular and at times serrate, white with yellow hues, grayish when mature.

3. Stipe

   6-11 x 1,5-2 cm, cylindraceous, at times enlarged downwards, often curved laterally, robust, firm, full, then fibrous, fibrillose-semi glossy, whitish with slight yellowish shades, furfuraceous white at the apex.

4. Spore Print

   White.

5. Flesh

   Firm, compact, consistent in the cap, fibrous in the stipe, white, yellowish in the outer part, turns to grayish at the air, after a long time. Floury and pleasant smell and taste.

6. Habitat

   Grows in late autumn, preferably in the pine woods, but also in the mixed woods of spruce and beech or even in the pure beech wood.

7. Microscopy

   Ovoid, guttulate, smooth spores, 5,5-6,05 × 4-4,4 µm. Clavate, tetrasporic basidia, without joints to buckle, 31,9-35, × 6,6-7,15 µm. Parallel trama with elongated hyphae wide from 5,5 to 9,9 µm. Epicutis formed by more or less parallel hyphae weakly gelatinous, wide from 3 to 6 µm.

Look-Alikes

1. Tricholoma pardinum

   Toxic and has a dry cap with dark grayish brown to black squamules over a pale gray ground color, larger spores, conspicuous cheilocystidia, and clamp connections.

2. Tricholoma equestre

   Has a yellow cap with a brown-olive central area; it has no significant odor.

3. Tricholoma virgatum

   Has a white or grayish stem and flesh having a sour or pungent taste.

4. Tricholoma sejunctum

   When, on the contrary, the cap is faded and the yellow hues do appear, it could be mistaken with T. portentosum, however, has the flesh with a bitter taste.

5. Tricholoma josserandii

   Has the flesh smelling of bedbug and sour taste which, however, comes sometime after the tasting.

Medicinal Properties

Antitumor effects

An extract of the fruit bodies inhibited the growth of Sarcoma 180 and Ehrlich solid cancers in mice by 70% and 60%, respectively (Ohtsuka et al., 1973).

Antioxidant/free radical scavenging activity

The total phenolic content of T. portentosum (in mg/g) was determined to be 6.57±0.31 in the cap, 3.91±0.17 in the stem, and 10.80±0.47 in the entire fruitbody. In the entire fruit body, this total included 0.40 mg/g flavonoids and 0.52 mg/g ascorbic acid (Barros et al., 2007a).

The antioxidant properties of T. portentosum have been evaluated (Ferreira et al., 2007a). Methanolic extracts from the entire mushroom, the cap and the stipe, separately, were screened for their reducing power and free radical scavenging capacity by chemical assays. The methanolic extract (at a concentration of 50 mg/ml) was shown to have excellent reducing power compared to the positive controls BHA and α-tocopherol. Specifically, expressed as an EC50 (mg/ml), the reducing power was 3.12, 3.69, and 4.82 for the entire fruit body, the cap, and the stem, respectively. In terms of free radical scavenging activity (FRSA), methanolic extracts from T. portentosum were only moderate in activity (22.9, 40.2 and >50% for the entire fruit body, the cap, and the stem, respectively).

Antibacterial/antifungal activity

A DMSO extract of T. portentosum was tested for its antibiotic activity against various bacteria. The extract was effective only against Gram+ bacteria (Bacillus cereus, B. subtilis) as well as the fungus Cryptococcus neoformans (causative agent of cryptococcosis) (Barros et al., 2007b).

History

When he described this species in 1821, the great Swedish mycologist Elias Magnus Fries named it Agaricus portentosus. Lucien Quélet transferred it to the genus Tricholoma in 1872, since when it has retained the name Tricholoma portentosum.

Synonyms of this Tricholoma portentosum include Agaricus portentosus Fr., Gyrophila portentosa (Fr.) Quél., and Melanoleuca portentosa (Fr.) Murill.

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 portentosum is Latin and according to my dictionary translates to portentous (an omen or sign of something important about to happen); however, some authorities state that it means prodigious, wonderful, or marvelous.

Photo sources:

Photo 1 - Author: Jerzy Opioła (CC BY-SA 4.0)

Photo 2 - Author: Mycowalt (CC BY-SA 4.0)

Photo 3 - Author: Adrien BENOIT à la GUILLAUME (CC BY-SA 4.0)

Photo 4 - Author: Adrien BENOIT à la GUILLAUME (CC BY-SA 4.0)

Photo 5 - Author: Jerzy Opioła (CC BY-SA 3.0)