Ruppia cirrhosa is a species of aquatic plant known by the common names spiral ditchgrass[2] and spiral tasselweed.

It is a thread-thin, grasslike perennial herb which grows from a rhizome anchored in the wet substrate.

It produces a long, narrow inflorescence tipped with two tiny flowers.

As the fruit develops the peduncle of the inflorescence curls into a neat spiral.

[4] Consequently, R. spiralis has nomenclatural priority over R. cirrhosa for the long- and coiled-pedunculate Ruppia.