Alismataceae (muskroot) is a family of perennial, aquatic plants, growing directly in water or on adjacent muddy banks. Stems are prostrate, the leaves simple, floating or held a little way above the water. Flowers are bisexual; a single plant produces both staminate and pistillate blooms. Flowers have three greenish sepals and three petals, colored pink or white. Both stamens and pistils are numerous.

There are six native alismataceae genera in the US, accounting for 42 species; the most widespread genus is sagittaria, with 30 species, the majority in the east of the country.