A hypanthium is a floral structure consisting of the bases of the sepals, petals, and stamens fused together. Its presence is diagnostic of many families, including the Rosaceae, Grossulariaceae, and Fabaceae. In some cases, it can be so deep, with such a narrow top, that the flower can look like it has an inferior ovary.
In eucalyptus this structure is commonly known as the 'gum nut'.
External links
Hypanthium images on MorphBank, a biological image database
