Blackboard Tree vs

Alstonia scholaris compared with Cliostomum leprosum

Key Differences

Blackboard Tree is Least Concern while is Vulnerable.

Taxonomic Classification

Rank	Blackboard Tree
Kingdom	Plantae (Plants)	Fungi (Fungi)
Phylum	Magnoliophyta (Flowering Plants)	Ascomycota (Sac Fungi)
Class	Magnoliopsida (Dicots)	Lecanoromycetes (Lecanoromycetes)
Order	Gentianales (Gentianales)	Lecanorales (Lecanorales)
Family	Apocynaceae	Ramalinaceae
Genus	Alstonia	Cliostomum
Species	Alstonia scholaris	Cliostomum leprosum

Conservation Status

Blackboard Tree

LC — Least Concern

VU — Vulnerable

Physical Characteristics

Attribute	Blackboard Tree
Diet	—	—
Average Lifespan	—	—
Average Length	—	—
Average Weight	—	—

Habitat & Geographic Range

Blackboard Tree

Habitat

Inhabits tropical and subtropical moist broadleaf forests and tropical and subtropical dry broadleaf forests within the Oceanian biogeographic realm.

Range

Distributed across Micronesia, Taiwan, and United States.

Habitat

Native to Europe and North America, inhabiting ecosystems characteristic of the region.

Range

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

Blackboard Tree

The Blackboard Tree (Alstonia scholaris) is a species in the genus Alstonia. It is currently classified as Least Concern on the IUCN Red List. Inhabits tropical and subtropical moist broadleaf forests and tropical and subtropical dry broadleaf forests within the Oceanian biogeographic realm.

Cliostomum leprosum is a crustose lichen-forming fungus in the family Ramalinaceae, notable for its powdery, leprose thallus that gives it a granular, mealy appearance on bark and wood substrates. Unlike many lichens that form well-defined, structured thalli, C. leprosum produces a loosely coherent sorediose crust ranging from pale greenish-grey to whitish, often colonizing deeply shaded, moist bark on deciduous and coniferous trees. The species is distributed across boreal and temperate forests of Europe and North America, with confirmed records from Norway, Sweden, and scattered locations in the United States. It photosynthesizes in partnership with green algal partners typical of crustose lichens. Cliostomum leprosum is assessed as Vulnerable due to its sensitivity to air pollution, particularly sulfur dioxide and nitrogen compounds that degrade lichen communities. Its decline is linked to habitat loss from intensive forestry, removal of veteran trees, and acidic deposition. Conservation efforts focus on preserving old-growth and semi-natural forest stands that provide suitable, low-disturbance bark microhabitats where this inconspicuous but ecologically significant lichen can persist.