See text Alisma is a genus of flowering plants in the family Alismataceae, members of which are commonly known as water-plantains.

The genus consists of aquatic plants with leaves either floating or submerged, found in a variety of still water habitats around the world (nearly worldwide).

Alisma flowers have six stamens, numerous free carpels in a single whorl, each with 1 ovule, and subventral styles.

The nineteenth century British art and social critic John Ruskin believed that the particular curve of the leaf-ribs of Alisma represented a model of 'divine proportion' and helped shape his theory of Gothic architecture.

These herbs usually flower in late May to early September, but this can vary with conditions.