Common Silver Hairgrass vs Compact Stonewort

Aira caryophyllea compared with Nitella tenuissima

Key Differences

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

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 tenuissima

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

EX — Extinct

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

Range

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

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 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 3 countries:

🇳🇴 Norway 🇸🇪 Sweden 🇺🇸 United States