Hydatellaceae, an obscure family of dwarf, aquatic flowering plants. is a survivor from before the evolutionary split between dicot and monocot plants. (A monocot has one leaf in the seed, like grass, and a dicot has two, like a bean.)
Previously, the Hydatellaceae were thought to be in the Poales (the order of flowering plants including grasses, sedges, bromeliads, etc.). Instead, they are early angiosperm plant family that belongs near the very root of the evolutionary tree of flowering plants. (The flowering plants began to diversify at least 135 million years ago, in the age of the dinosaurs.)
Through DNA analysis and morphological investigations, the researchers found evidence that the Hydatellaceae are more closely related to the Nymphaeaceae, or water lilies.
The research team was led by scientists at the UBC Botanical Garden & Centre for Plant Research. The researchers, led by UBC Associate Professor Sean Graham and his graduate students Jeffery M. Saarela (now at the Canadian Museum of Nature) and Hardeep Rai.
The discovery was announced in the March 15, 2007 issue of Nature. As noted in the abstract to the article, this discovery rewrites our understanding of angiosperm structural and reproductive biology, physiology, ecology and taxonomy”.