coastal quillwort vs Common Quillwort

Isoetes maritima compared with Isoetes lacustris

Taxonomic Classification

Rank	coastal quillwort	Common Quillwort
Kingdom same	Plantae (พืช)	Plantae (พืช)
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 lacustris

Evolutionary Relationship

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

Conservation Status

coastal quillwort

LC — Least Concern

Common Quillwort

LC — Least Concern

Physical Characteristics

Attribute	coastal quillwort	Common 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.

Common Quillwort

Habitat

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

Range

Found across Europe (5 countries) and North America (Canada, United States).

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.

Common Quillwort

The Common Quillwort, <em>Isoetes lacustris</em>, is an aquatic vascular plant in the family Isoetaceae, a relict lineage representing one of the most ancient groups of vascular plants, related to the giant lycopsid trees of the Carboniferous period. It is native to Europe and North America, where it typically grows submerged in cool, clear, oligotrophic lakes and slow rivers on sandy or gravelly substrates at low to mid elevations. <em>Isoetes lacustris</em> is characterized by its rosette of quill-like, hollow, dark green leaves emerging from a lobed corm-like base, typically reaching 10 to 20 centimeters in length. The sporangia, which produce megaspores and microspores, are embedded at the swollen bases of the leaves. The species reproduces via spores and is entirely submerged, absorbing carbon dioxide and nutrients from the sediment and water column. It is highly sensitive to water quality deterioration, including eutrophication and acidification, and its presence is considered an indicator of pristine lacustrine conditions. The Common Quillwort is assessed as Least Concern on the IUCN Red List. Biological traits such as average lifespan, body size, and specific dietary preferences remain poorly documented for this species.

Shared Countries

Both species can be found in 2 countries:

🇨🇦 Canada 🇳🇴 Norway