coastal quillwort vs River Quillwort

Isoetes maritima compared with Isoetes fluitans

Key Differences

• coastal quillwort is Least Concern while River Quillwort is Endangered.

Taxonomic Classification

Rank	coastal quillwort	River Quillwort
Kingdom same	Plantae (Plants)	Plantae (Plants)
Phylum same	Tracheophyta	Tracheophyta
Class same	Lycopodiopsida (Lycopodiopsida)	Lycopodiopsida (Lycopodiopsida)
Order same	Isoetales (Isoetales)	Isoetales (Isoetales)
Family same	Isoetaceae	Isoetaceae
Genus same	Isoetes	Isoetes
Species	Isoetes maritima	Isoetes fluitans

Evolutionary Relationship

coastal quillwort and River Quillwort share a common ancestor at the Genus level: Isoetes.

Conservation Status

coastal quillwort

LC — Least Concern

River Quillwort

EN — Endangered

Physical Characteristics

Attribute	coastal quillwort	River Quillwort
Diet	—	—
Average Lifespan	—	—
Average Length	—	—
Average Weight	—	—

Habitat & Geographic Range

coastal quillwort

Habitat

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

Range

Distributed across Canada and Norway.

River Quillwort

coastal quillwort

Coastal quillwort (Isoetes maritima) is an aquatic or semi-aquatic lycophyte in the family Isoetaceae, native to Atlantic coastal regions of North America and western Europe, including eastern Canada, the northeastern United States, Ireland, the United Kingdom, and northern France. It grows in shallow brackish or slightly saline pools, coastal lagoons, rock crevices, and wet hollows that experience seasonal drying. Like all Isoetes species, it has quill-like leaves arising from a corm-like base and reproduces via spores produced in sporangia embedded at leaf bases. Coastal quillwort occupies a specialised niche at the intersection of marine and freshwater habitats, tolerating fluctuating salinity levels. Its populations are often small and localised, making them vulnerable to habitat modification, drainage, and coastal development. The IUCN assesses coastal quillwort as Least Concern overall, but many regional populations are protected or listed as threatened. As an ancient lineage of vascular plants, Isoetes species represent living relicts of the Carboniferous-era lycopsid forests and hold significant evolutionary interest for botanists.