Bitter Knight vs Coalman

Tricholoma acerbum compared with Tricholoma portentosum

Key Differences

• Bitter Knight is Endangered while Coalman is Data Deficient.

Taxonomic Classification

Rank	Bitter Knight	Coalman
Kingdom same	Fungi (เห็ดรา)	Fungi (เห็ดรา)
Phylum same	Basidiomycota (Club Fungi)	Basidiomycota (Club Fungi)
Class same	Agaricomycetes (Mushrooms)	Agaricomycetes (Mushrooms)
Order same	Agaricales (Gilled Mushrooms)	Agaricales (Gilled Mushrooms)
Family same	Tricholomataceae	Tricholomataceae
Genus same	Tricholoma	Tricholoma
Species	Tricholoma acerbum	Tricholoma portentosum

Evolutionary Relationship

Bitter Knight and Coalman share a common ancestor at the Genus level: Tricholoma.

Conservation Status

Bitter Knight

EN — Endangered

Coalman

DD — Data Deficient

Physical Characteristics

Attribute	Bitter Knight	Coalman
Diet	—	—
Average Lifespan	—	—
Average Length	—	—
Average Weight	—	—

Habitat & Geographic Range

Bitter Knight

Habitat

Typically found in forest floors, decomposing wood, and soil ecosystems.

Range

Distributed across Belgium, Norway, and Sweden. Currently classified as Endangered on the IUCN Red List, this species faces significant conservation challenges across its range.

Coalman

Habitat

Typically found in forest floors, decomposing wood, and soil ecosystems.

Range

Found across Europe (5 countries) and North America (United States).

Bitter Knight

The Bitter Knight (Tricholoma acerbum) is a species in the genus Tricholoma. It is currently classified as Endangered on the IUCN Red List. Typically found in forest floors, decomposing wood, and soil ecosystems.

Coalman

Tricholoma portentosum, commonly called the coalman or soapy knight, is a large, prized edible mushroom in the family Tricholomataceae forming ectomycorrhizal associations with conifers, especially pines and spruces, across temperate forests of Europe and North America. The fruiting body features a grey to blackish fibrous cap 6–12 centimeters in diameter with a wavy, often undulating margin, white to pale yellow gills with a slightly soapy odour, and a white stem with grey streaks. It typically fruits in autumn in pine forests and mixed coniferous-deciduous woodland, where its underground mycorrhizal network supports tree health and nutrient uptake. Tricholoma portentosum is considered a fine edible species in several European countries, particularly in Spain, Poland, and Italy, where it is collected commercially and sold in markets. The genus Tricholoma contains numerous similar grey or silvery species, making field identification challenging and requiring careful attention to habitat, odour, and microscopic features. The species is classified as Data Deficient by the IUCN, reflecting insufficient baseline population data to determine whether it is declining. Broader declines in fruiting body abundance of ectomycorrhizal fungi across Europe have been documented through long-term monitoring, attributed primarily to atmospheric nitrogen deposition altering forest nitrogen dynamics.

Shared Countries

Both species can be found in 3 countries:

🇧🇪 Belgium 🇳🇴 Norway 🇸🇪 Sweden