Compact Stonewort vs Dark Stonewort

Nitella tenuissima compared with Nitella opaca

Key Differences

• Compact Stonewort is Extinct while Dark Stonewort is Least Concern.

Taxonomic Classification

Rank	Compact Stonewort	Dark Stonewort
Kingdom same	Plantae (Plants)	Plantae (Plants)
Phylum same	Charophyta (Charophyta)	Charophyta (Charophyta)
Class same	Charophyceae (Charophyceae)	Charophyceae (Charophyceae)
Order same	Charales (Charales)	Charales (Charales)
Family same	Characeae	Characeae
Genus same	Nitella	Nitella
Species	Nitella tenuissima	Nitella opaca

Evolutionary Relationship

Compact Stonewort and Dark Stonewort share a common ancestor at the Genus level: Nitella.

Conservation Status

Compact Stonewort

EX — Extinct

Dark Stonewort

LC — Least Concern

Physical Characteristics

Attribute	Compact Stonewort	Dark Stonewort
Diet	—	—
Average Lifespan	—	—
Average Length	—	—
Average Weight	—	—

Habitat & Geographic Range

Compact Stonewort

Habitat

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

Range

Distributed across Brazil, Norway, Sweden, Taiwan, and United States.

Dark Stonewort

Habitat

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

Range

Distributed across Brazil, Denmark, Norway, Sweden, and United States.

Compact Stonewort

<em>Nitella tenuissima</em>, a stonewort formerly found in fresh and brackish water habitats, was a member of the charophyte family Characeae — the algal lineage most closely related to land plants. Historical records document its occurrence across Brazil, Norway, Sweden, Taiwan, and the United States, where it inhabited clear, oligotrophic lakes, ponds, and slow-flowing water bodies with low nutrient levels. Like other Nitella species, it was a delicate, translucent, submerged aquatic plant lacking the calcium carbonate encrustation of related genera, forming low-growing mats on soft sediments in well-illuminated shallow water. The species played a role in aquatic ecosystems by stabilising lake sediments, contributing to water clarity, and providing microhabitat for invertebrates and small aquatic organisms. <em>Nitella tenuissima</em> is classified as Extinct by the IUCN, having not been recorded from any of its former localities despite targeted searches. The primary causes of its extinction are believed to be widespread eutrophication of freshwater habitats driven by agricultural nutrient runoff and sewage discharge, which eliminated the clear, nutrient-poor conditions on which the species depended. The loss of this stonewort is emblematic of the broader decline of freshwater charophyte diversity across the Northern Hemisphere. Biological traits including historical morphological measurements and reproductive parameters are documented only in sparse historical herbarium specimens and early botanical literature.

Shared Countries

Both species can be found in 4 countries:

🇧🇷 Brazil 🇳🇴 Norway 🇸🇪 Sweden 🇺🇸 United States