Brook Alder vs Common Tarcrust

Alnus maritima compared with Diatrype stigma

Key Differences

Brook Alder is Endangered while Common Tarcrust is Not Evaluated.

Taxonomic Classification

Rank	Brook Alder	Common Tarcrust
Kingdom	Plantae (Plants)	Fungi (Fungi)
Phylum	Magnoliophyta (Flowering Plants)	Ascomycota (Sac Fungi)
Class	Magnoliopsida (Dicots)	Sordariomycetes (Sordariomycetes)
Order	Fagales (Beeches & Oaks)	Xylariales (Xylariales)
Family	Betulaceae	Diatrypaceae
Genus	Alnus	Diatrype
Species	Alnus maritima	Diatrype stigma

Conservation Status

Brook Alder

EN — Endangered

Common Tarcrust

NE — Not Evaluated

Physical Characteristics

Attribute	Brook Alder	Common Tarcrust
Diet	—	—
Average Lifespan	—	—
Average Length	—	—
Average Weight	—	—

Habitat & Geographic Range

Brook Alder

Habitat

Typically found in diverse terrestrial habitats from tropical forests to temperate regions.

Range

Distributed across Belgium, France, Netherlands, and United Kingdom. Currently classified as Endangered on the IUCN Red List, this species faces significant conservation challenges across its range.

Common Tarcrust

Habitat

Native to Europe, inhabiting ecosystems characteristic of the region.

Range

Distributed across Belgium, Denmark, Norway, Portugal, and Sweden.

Brook Alder

The Brook Alder (Alnus maritima) is a species in the genus Alnus. It is currently classified as Endangered on the IUCN Red List. Typically found in diverse terrestrial habitats from tropical forests to temperate regions.

Common Tarcrust

<em>Diatrype stigma</em>, the common tarcrust, is a saprotrophic fungus in the family Diatrypaceae, found across Belgium, Denmark, Norway, Portugal, and Sweden, as well as more broadly in Europe and temperate regions globally. It grows as a crust-like, charcoal-black stromata on the dead bark and branches of deciduous hardwoods, particularly hazel, beech, and alder. The fruiting bodies are typically flat to slightly raised, dark gray to black patches that contain numerous embedded perithecia in which ascospores are produced. This fungus plays an important ecological role as a decomposer, breaking down dead woody material and recycling nutrients in forest ecosystems. It is Not Evaluated on the IUCN Red List; given its broad distribution on common substrates, it is generally considered widespread. The species reproduces via wind-dispersed ascospores released from the perithecia. Diet, as a saprotrophic organism, consists of dead organic woody matter. Biological traits such as colony growth rates, spore output, and longevity remain poorly documented in standardized quantitative assessments.