Common Quillwort vs Sardinian Quillwort

Isoetes lacustris compared with Isoetes tiguliana

Taxonomic Classification

Rank	Common Quillwort	Sardinian 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 lacustris	Isoetes tiguliana

Evolutionary Relationship

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

Conservation Status

Common Quillwort

LC — Least Concern

Sardinian Quillwort

LC — Least Concern

Physical Characteristics

Attribute	Common Quillwort	Sardinian Quillwort
Diet	—	—
Average Lifespan	—	—
Average Length	—	—
Average Weight	—	—

Habitat & Geographic Range

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).

Sardinian Quillwort

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.