Hypanthium

A hypanthium is a floral

Flower

A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants . The biological function of a flower is to effect reproduction, usually by providing a mechanism for the union of sperm with eggs...

 structure consisting of the bases of the sepals, petals, and stamens fused together. Its presence is diagnostic of many families, including the Rosaceae

Rosaceae

Rosaceae are a medium-sized family of flowering plants, including about 2830 species in 95 genera. The name is derived from the type genus Rosa. Among the largest genera are Alchemilla , Sorbus , Crataegus , Cotoneaster , and Rubus...

, Grossulariaceae, and Fabaceae

Fabaceae

The Fabaceae or Leguminosae, commonly known as the legume, pea, or bean family, is a large and economically important family of flowering plants. The group is the third largest land plant family, behind only the Orchidaceae and Asteraceae, with 730 genera and over 19,400 species...

. In some cases, it can be so deep, with such a narrow top, that the flower can appear to have an inferior ovary

Ovary (plants)

In the flowering plants, an ovary is a part of the female reproductive organ of the flower or gynoecium. Specifically, it is the part of the pistil which holds the ovule and is located above or below or at the point of connection with the base of the petals and sepals...

.

In eucalyptus

Eucalyptus

Eucalyptus is a diverse genus of flowering trees in the myrtle family, Myrtaceae. Members of the genus dominate the tree flora of Australia...

 this structure is commonly known as the gum nut.

Geometrics

The various shapes of the hypanthium structure are useful in species identification. A diversity of geometric forms are associated with the hypanthium including obconic

Obconic

In botany, an obconic is an inverted cone shape. The term is most frequently applied to certain fruit or hypanthium structures with the apical end attached to the stem; however, less frequently the usage may apply to the pistil structure. In the case of fungi the designation is often made to the...

 forms such as found in Toyon

Toyon

Heteromeles arbutifolia , and commonly known as Toyon, is a common perennial shrub native to California down to Baja California....

 or saucer-shaped as found in some species of the genus Mitellastra.

External links

• Hypanthium images on MorphBank, a biological image database