Blackboard Tree vs

Alstonia scholaris compared with Chrysococcus radians

Key Differences

• Blackboard Tree is Least Concern while is Not Evaluated.

Taxonomic Classification

Rank	Blackboard Tree
Kingdom	Plantae (Plants)	Chromista (Chromista)
Phylum	Magnoliophyta (Flowering Plants)	Ochrophyta (Ochrophyta)
Class	Magnoliopsida (Dicots)	Chrysophyceae (Chrysophyceae)
Order	Gentianales (Gentianales)	Chromulinales (Chromulinales)
Family	Apocynaceae	Dinobryaceae
Genus	Alstonia	Chrysococcus
Species	Alstonia scholaris	Chrysococcus radians

Conservation Status

Blackboard Tree

LC — Least Concern

NE — Not Evaluated

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 South America, inhabiting ecosystems characteristic of the region.

Range

Distributed across Brazil, Denmark, and Sweden.

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.

Chrysococcus radians is a freshwater chrysophyte microalga in the genus Chrysococcus, class Chrysophyceae, order Chromulinales. The species epithet radians — radiating — describes a lorica with radiating spine-like projections or extensions emanating from the central body of the outer case, a morphological feature readily distinguishable under light microscopy. Radiating processes on chrysophyte loricas are thought to increase the effective surface area of the cell, potentially slowing sinking and maintaining the organism in the illuminated photic zone of freshwater lakes. C. radians has been documented from Norwegian and Swedish freshwater systems, with additional records from Denmark, consistent with a broader northern European distribution of this species. Scandinavian lakes, particularly the oligotrophic highland lakes of Norway and Sweden, harbor diverse chrysophyte communities in which Chrysococcus and related genera are frequently dominant components during spring and autumn mixing periods. The species inhabits the limnetic zone, where it engages in photosynthesis using the characteristic golden-brown chrysophyte pigments — chlorophylls a and c combined with fucoxanthin. Like other genus members, C. radians may also practice mixotrophic feeding on bacteria and dissolved organic matter, providing nutritional flexibility in oligotrophic environments. Siliceous stomatocysts produced by chrysophytes can survive in lake sediments and provide paleolimnological records of past environmental change. C. radians has not been evaluated under IUCN Red List criteria and is classified as Not Evaluated.