Common Silver Hairgrass vs Compact Stonewort

Aira caryophyllea compared with Nitella mucronata

Key Differences

• Common Silver Hairgrass is Endangered while Compact Stonewort is Vulnerable.

Taxonomic Classification

Rank	Common Silver Hairgrass	Compact Stonewort
Kingdom same	Plantae (Plants)	Plantae (Plants)
Phylum	Magnoliophyta (Flowering Plants)	Charophyta (Charophyta)
Class	Liliopsida (Monocots)	Charophyceae (Charophyceae)
Order	Poales (Grasses)	Charales (Charales)
Family	Poaceae (Grass Family)	Characeae
Genus	Aira	Nitella
Species	Aira caryophyllea	Nitella mucronata

Evolutionary Relationship

Common Silver Hairgrass and Compact Stonewort share a common ancestor at the Kingdom level: Plantae. (Plants)

Conservation Status

Common Silver Hairgrass

EN — Endangered

Compact Stonewort

VU — Vulnerable

Physical Characteristics

Attribute	Common Silver Hairgrass	Compact Stonewort
Diet	—	—
Average Lifespan	—	—
Average Length	—	—
Average Weight	—	—

Habitat & Geographic Range

Common Silver Hairgrass

Habitat

Found across multiple habitat types including tropical and subtropical moist broadleaf forests, tropical and subtropical grasslands and savannas, and flooded grasslands and savannas, among 11 distinct biome types. Populations are also found in montane and highland environments at higher elevations.

Range

Widely distributed across Africa (Cameroon), Asia (Japan, South Korea), Europe (6 countries), North America (4 countries), Oceania and the Pacific (Australia), and South America (4 countries). Currently classified as Endangered on the IUCN Red List, this species faces significant conservation challenges across its range.

Compact Stonewort

Habitat

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

Range

Widely distributed across Europe (4 countries), North America (United States), and South America (Brazil). Currently classified as Vulnerable on the IUCN Red List, this species faces significant conservation challenges across its range.

Common Silver Hairgrass

<em>Aira caryophyllea</em>, commonly known as Common Silver Hairgrass, is a slender annual grass belonging to the family Poaceae within the order Poales. This delicate grass is currently classified as Endangered on the IUCN Red List, reflecting significant conservation concern despite its historically broad distribution. It is typically found across a remarkable diversity of biome types, including tropical and subtropical moist broadleaf forests, grasslands, savannas, and flooded habitats, demonstrating notable ecological versatility. Its geographic range spans multiple continents, with documented populations in Africa (Cameroon), Asia (Japan, South Korea), Europe, North America, Australia, and South America. As an annual grass, it completes its life cycle within a single growing season, reproducing via wind-dispersed seeds. The inflorescence typically bears silvery, shimmering spikelets that give the species its common name. Biological traits such as average lifespan, body dimensions, and dietary specifics follow typical patterns for annual grasses — drawing nutrients from soil through root absorption rather than consuming other organisms. The endangered status suggests populations may be declining due to habitat loss, land-use change, or invasive species pressure across parts of its range.

Compact Stonewort

<em>Nitella mucronata</em>, compact stonewort, is a freshwater macroalga in the family Characeae, belonging to the charophyte lineage considered the closest algal relatives of land plants. It has been recorded from fresh and brackish water bodies in Belgium, Brazil, Denmark, Norway, Sweden, and the United States, inhabiting clear, nutrient-poor lakes, ponds, and slow-moving streams. Stoneworts of the genus Nitella are delicate, translucent plants lacking the calcium carbonate encrustation typical of the related genus Chara, growing submerged in well-lit, oligotrophic aquatic environments. They typically form dense underwater meadows that provide important habitat for invertebrates and small fish, while also stabilising sediments and contributing to water clarity through nutrient uptake. <em>Nitella mucronata</em> is classified as Vulnerable by the IUCN, reflecting sensitivity to water quality deterioration, eutrophication from agricultural runoff and sewage, and the loss of clear, unpolluted water bodies across its range in Europe and beyond. The species is particularly vulnerable to increased phosphorus and nitrogen loading, which promotes algal blooms that shade out submerged macrophytes. Biological traits including average lifespan, reproduction rates, and morphological measurements remain poorly documented compared to more widespread charophyte species. Conservation of <em>Nitella mucronata</em> depends on improving water quality in its freshwater habitats and protecting oligotrophic water bodies from nutrient pollution.

Shared Countries

Both species can be found in 5 countries:

🇧🇪 Belgium 🇩🇰 Denmark 🇳🇴 Norway 🇸🇪 Sweden 🇺🇸 United States