Flora of Northern Ireland
Isoetes lacustris
© Ian Dodkins
Isoetes lacustris
(Map updated: March 2008)

A strange submerged aquatic plant, rather resembling a small spring onion, but actually a relative of the clubmosses and ferns. The stem is very short and completely hidden by the expanded whitish bases of the long, narrow, tubular leaves. The leaves vary in length but are normally between about 2 - 6 inches long. Spores are produced in the bases of the leaves.

The plant grows rooted in the mud of lakes, mainly in upland districts, and is normally not visible to the casual observer, but in autumn, after storms and gales have disturbed the lake waters, many plants are uprooted and float to the surface, where they collect in drifts around the lake margins.

All names: Isoetes lacustris L.