In Alisma, sepals are typically broadly ovate or nearly round, featuring a distinct translucent or light green (like here) border contrasted with greener, thicker center. Unlike the delicate petals, sepals persist on the plant into the fruiting stage. In this species, petals relatively small (at most 2.5 × 2 mm), only a little longer than sepals (in the other species they are noticeably longer).