Old plants were lost in the grass

An obscure family of small, narrow-leaved water plants that have for years been classified as oddball relatives of grasses turns out to represent one of the most ancient surviving lineages of flowering plants, researchers say.

NEWEST ANCIENTS. What look like individual flowers on Trithuria submersa, a member of the Hydatellaceae family, are actually bouquets of several stripped-down flowers surrounded by modified leaflike structures.