Archaefructus

Archaefructus is an extinct genus of herbaceous aquatic seed plants. Its fossils come from the Yixian Formation in northeastern China, about 125 million years ago in the early Cretaceous. "Archaefructus" is the earliest known genus of flowering plants.
It lacks sepals and petals. Its reproductive organs, carpels and stamens, are produced on an elongate stem rather than condensed into a flower as in modern angiosperms. Archaefructaceae has been proposed as a new basal angiosperm family. 
An alternate interpretation of the same fossil has the long stem as an inflorescence rather than a flower, with staminate (male) flowers below and pistillate (female) flower above. The discovery of "Archaefructus eoflora" supports this interpretation, because a bisexual flower is present between staminate and pistillate organs. If this is correct, "Archaefructus" may not be basal within angiosperms, but it may be close to the Nymphaeales or the basal eudicots.