Blackboard Tree vs

Alstonia scholaris compared with Chrysococcus cystophorus

Key Differences

Blackboard Tree is Least Concern while is Not Evaluated.

Taxonomic Classification

Rank	Blackboard Tree
Kingdom	Plantae (растения)	Chromista (хромисты)
Phylum	Magnoliophyta (магнолиофиты)	Ochrophyta (охрофитовые водоросли)
Class	Magnoliopsida (Dicots)	Chrysophyceae (Золотистые водоросли)
Order	Gentianales (горечавкоцветные)	Chromulinales (Chromulinales)
Family	Apocynaceae	Dinobryaceae
Genus	Alstonia	Chrysococcus
Species	Alstonia scholaris	Chrysococcus cystophorus

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, inhabiting ecosystems characteristic of the region.

Range

Distributed across Norway 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 cystophorus is a unicellular freshwater chrysophyte microalga in the genus Chrysococcus, family Chromulinaceae, class Chrysophyceae. The specific epithet cystophorus, meaning cyst-bearing, references this species' relationship with siliceous cyst formation — a shared feature across many chrysophytes that produce species-specific resting stages called stomatocysts or statospores. In chrysophytes, the stomatocyst is a silicified internal cyst with a characteristic plug-sealed pore, and its morphology is often used as an additional taxonomic character in species identification. C. cystophorus inhabits freshwater environments and has been recorded from Norwegian waters along with other Scandinavian localities, fitting the pattern of chrysophyte species diversity documented through freshwater surveys in the region. Chrysococcus cells are enclosed within a lorica — a proteinaceous or organic outer vessel — from which flagella emerge for locomotion. The lorica shape and ornamentation, along with the dimensions and flagellar arrangement, are primary characters used for species identification. Like other chrysophytes, C. cystophorus is golden-brown in color owing to chlorophylls a and c together with fucoxanthin pigments in the chloroplast. Chrysococcus species function as primary producers in freshwater plankton communities, particularly in oligotrophic lakes where smaller algae outcompete larger taxa. C. cystophorus has not been evaluated under IUCN Red List criteria and is listed as Not Evaluated, consistent with the general status of freshwater microalgal taxa.