Isoetes lacustris

About this plant

Isoetes lacustris, the lake quillwort, is a submerged lycophyte of cool, clear northern lakes rather than a conventional tropical aquarium plant. It is native from Greenland through Europe to Siberia and forms a compact crown of stiff, quill-like green leaves. In nature it is associated with nutrient-poor, often soft and acidic water and grows slowly from a short corm-like base. Long-term culture is best attempted in an unheated specialist aquarium with clean, oxygen-rich water, a stable mineral substrate and minimal disturbance. Warm tropical conditions and nutrient-rich water are poor matches for its natural ecology. Propagation occurs through spores; established clumps may also be divided carefully when separate growing points are present. Because reliable aquarium-specific pH, hardness and fertiliser ranges are scarce, generic nutrient values are not used in this profile. Isoetes lacustris is primarily of interest for cold-water, native-plant and botanical displays.