Ruppiaceae

Submersed aquatic non-woody (herbaceous) annuals or rarely perennials of salty or brackish water in pools in salt marshes and in ditches. Stems often rooting at lower nodes. Leaves alternate to nearly opposite, leaf blade linear, very narrow, with 1 vein; leaf edges smooth near base of leaf blade, with tiny teeth toward tip.

Flowers very small, usually 2 in spikes at top of stem. Each spike initially enclosed with the sheath of the uppermost leaf, on a stalk that becomes longer and more and more spiral twisted after fertilization. Each flower producing both pollen and seeds. Sepals and petal none. Stamens 2, separate. Carpels 4, separate, pistils mostly 4 (sometimes up to 16), separate, each on a stalk that becomes longer in fruit; ovary located above point of attachment of other flower parts (superior); style none; stigma 1. Fruits form an umbel-like cluster, each fruit resembling a stone fruit, with a beak that is upright to curved outward, and 1 seed.