Isoetes lacustris (Lake Quillwort) Care Guide
Isoetes lacustris, the lake quillwort, is a cold-water rosette lycophyte of clean European and North American lakes, kept as a slow biotope accent plant.
Overview
Isoetes lacustris, the lake quillwort or Merlin's grass, is a boreal lycophyte that forms a rosette of hollow, quill-like leaves arising from a central corm. It is a slow-growing spore-producing plant suited to biotope-style aquaria with cold, soft, oxygen-rich water.
Taxonomy
- Family: Isoetaceae
- Genus: Isoetes
- Scientific name: Isoetes lacustris
- Common names: lake quillwort, Merlin's grass
Habitat
The species is native to both sides of the northern Atlantic, including Scandinavia, the British Isles, Iceland, parts of continental Europe, eastern Canada, the Great Lakes region and the northeastern United States. It grows submerged in clear, oligotrophic lakes. NatureServe lists its conservation status as Secure.
Tank requirements
- Temperature: 8-20 °C (46-68 °F)
- pH: 6.0-7.0
- GH: 2-8 °dGH
- Maximum height: about 20 cm
- Lighting: medium
- CO2: not required
- Substrate: sand
- Placement: midground
Growth and care
Growth is slow and the plant is considered demanding, requiring soft, well-oxygenated and cool water that mirrors its native lakes. Like other quillworts it uses crassulacean acid metabolism and aquatic species can absorb carbon dioxide through the roots from the sediment rather than from the leaves.
Propagation
The genus is heterosporous, reproducing by megaspores and microspores rather than seeds; the gametophytes develop inside the spores, and dispersal is water-dependent.