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.