Clustered Stonewort vs Common Least Skipper

Tolypella glomerata compared with Ancyloxypha numitor

Key Differences

• Clustered Stonewort is Vulnerable while Common Least Skipper is Least Concern.

Taxonomic Classification

Rank	Clustered Stonewort	Common Least Skipper
Kingdom	Plantae (Plants)	Animalia (Animals)
Phylum	Charophyta (Charophyta)	Arthropoda (Arthropods)
Class	Charophyceae (Charophyceae)	Insecta (Insects)
Order	Charales (Charales)	Lepidoptera (Butterflies & Moths)
Family	Characeae	Hesperiidae
Genus	Tolypella	Ancyloxypha
Species	Tolypella glomerata	Ancyloxypha numitor

Conservation Status

Clustered Stonewort

VU — Vulnerable

Common Least Skipper

LC — Least Concern

Physical Characteristics

Attribute	Clustered Stonewort	Common Least Skipper
Diet	—	—
Average Lifespan	—	—
Average Length	—	—
Average Weight	—	—

Habitat & Geographic Range

Clustered Stonewort

Habitat

Native to Europe, inhabiting ecosystems characteristic of the region.

Range

Distributed across Denmark, Norway, and Sweden. Currently classified as Vulnerable on the IUCN Red List, this species faces significant conservation challenges across its range.

Common Least Skipper

Habitat

Typically found in virtually all terrestrial and freshwater habitats.

Range

Distributed across Canada and United States.

Clustered Stonewort

Tolypella glomerata, the clustered stonewort, is a charophyte alga in the family Characeae, found in calcareous, nutrient-poor freshwater habitats including lakes, ponds, ditches, and slow-flowing water in northwestern and northern Europe. Charophytes are macroscopic green algae with a distinctive whorl-like arrangement of branches and a complex, plant-like structure that distinguishes them from other algae. T. glomerata is encrusted with calcium carbonate deposits (hence 'stonewort'), giving it a pale, grey-green appearance and rough texture. The species colonizes clear, low-nutrient water over fine sediment or gravel substrates where competition from vascular plants is reduced by nutrient limitation. It is listed as Vulnerable by the IUCN, reflecting significant declines driven by eutrophication (nutrient enrichment from agriculture and sewage), which promotes the growth of vascular plants and phytoplankton that shade out stoneworts. Drainage, water abstraction, and peat cutting also threaten its habitats. Charophyte diversity has declined substantially across lowland Europe and North America over the past century, with many species becoming locally extinct from sites they once colonized.

Common Least Skipper

The Common Least Skipper (<em>Ancyloxypha numitor</em>) is a small butterfly in the family Hesperiidae, classified as Least Concern on the IUCN Red List. It is native to Canada and the United States, where it typically inhabits virtually all terrestrial and freshwater habitats within its range, showing a particular affinity for moist, grassy areas near water. The species is among the smallest skippers in North America, characterized by orange and brown wing coloration and a rapid, low-flying flight pattern close to vegetation. Adults typically nectar on small flowers while larvae feed on grasses, particularly those in wet meadows, marshes, stream margins, and disturbed grassy areas. The Common Least Skipper is frequently observed in wetland margins, wet prairies, and roadsides with rank grass growth. Its wide distribution across North America and habitat generalism across moist grassland and wetland types support its stable population and Least Concern conservation status. Biological traits of this species remain poorly documented in the scientific literature.