angiosperms Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (). The term angiosperm is derived from the Greek words (; 'container, vessel') and (; 'seed'), meaning that the seeds are enclosed within a fruit. T ...

, a hypanthium or floral cup is a structure where basal portions of the calyx, the corolla, and the

stamen The stamen (: stamina or stamens) is a part consisting of the male reproductive organs of a flower. Collectively, the stamens form the androecium., p. 10 Morphology and terminology A stamen typically consists of a stalk called the filament ...

s form a cup-shaped tube. It is sometimes called a floral tube, a term that is also used for corolla tube and

calyx tube A sepal () is a part of the flower of angiosperms (flowering plants). Usually green, sepals typically function as protection for the flower in bud, and often as support for the petals when in bloom., p. 106 Etymology The term ''sepalum'' ...

."Lecture 7 – Pharmacognosy and Botany (1st Semester)" ''Azerbaijan Medical University'', n.d. Accessed May 9, 2025. It often contains the

nectar Nectar is a viscous, sugar-rich liquid produced by Plant, plants in glands called nectaries, either within the flowers with which it attracts pollination, pollinating animals, or by extrafloral nectaries, which provide a nutrient source to an ...

ies of the plant. It is present in many plant families, although varies in structural dimensions and appearance. This differentiation between the hypanthium in particular species is useful for

identification Identification or identify may refer to: *Identity document, any document used to verify a person's identity Arts, entertainment and media * ''Identify'' (album) by Got7, 2014 * "Identify" (song), by Natalie Imbruglia, 1999 * ''Identification ...

. Some

geometric Geometry (; ) is a branch of mathematics concerned with properties of space such as the distance, shape, size, and relative position of figures. Geometry is, along with arithmetic, one of the oldest branches of mathematics. A mathematician w ...

forms are

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 ca ...

shapes, as in toyon (''Heteromeles''), whereas some are saucer-shaped, as in '' Mitella caulescens''. Its presence is diagnostic of many

families Family (from ) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictability, structure, and safety as ...

, including the

Rosaceae Rosaceae (), the rose family, is a family of flowering plants that includes 4,828 known species in 91 genera. The name is derived from the type genus '' Rosa''. The family includes herbs, shrubs, and trees. Most species are deciduous, but som ...

Grossulariaceae ''Ribes'' () is a genus of about 200 known species of flowering plants, most of them native to the temperate regions of the Northern Hemisphere. The species may be known as various kinds of currants, such as redcurrants, blackcurrants, and whi ...

, and

Fabaceae Fabaceae () or Leguminosae,International Code of Nomen ...

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

ovary The ovary () is a gonad in the female reproductive system that produces ova; when released, an ovum travels through the fallopian tube/ oviduct into the uterus. There is an ovary on the left and the right side of the body. The ovaries are end ...

the ovary is below the other attached floral parts. The hypanthium is known by different common names in differing species. In the

eucalypt Eucalypt is any woody plant with Capsule (fruit), capsule fruiting bodies belonging to one of seven closely related genera (of the tribe Eucalypteae) found across Australia: ''Eucalyptus'', ''Corymbia'', ''Angophora'', ''Stockwellia'', ''Allosyn ...

s, it is referred to as the ''gum nut''; in roses it is called the '' hip''.

Variations in plant species

In myrtles, the hypanthium can either surround the ovary loosely or tightly; in some cases, it can be fused to the walls of the ovary. It can vary in length. The rims around the outside of the hypanthium contain the calyx lobes or free sepals,

petal Petals are modified leaves that form an inner whorl surrounding the reproductive parts of flowers. They are often brightly coloured or unusually shaped to attract pollinators. All of the petals of a flower are collectively known as the ''corol ...

s and either the stamen or multiple stamen that are attached at one or two points. The flowers of the

rose A rose is either a woody perennial plant, perennial flowering plant of the genus ''Rosa'' (), in the family Rosaceae (), or the flower it bears. There are over three hundred Rose species, species and Garden roses, tens of thousands of cultivar ...

family (

) always have some type of hypanthium or at least a floral cup from which the sepals, petals and stamens all arise, which is lined with tissue known as ''nectaries'', which produce

, a

sweet Sweetness is a basic taste most commonly perceived when eating foods rich in sugars. Sweet tastes are generally regarded as pleasurable. In addition to sugars like sucrose, many other chemical compounds are sweet, including aldehydes, ketones, ...

substance that attracts to the flower birds and bees, which receive

pollen Pollen is a powdery substance produced by most types of flowers of seed plants for the purpose of sexual reproduction. It consists of pollen grains (highly reduced Gametophyte#Heterospory, microgametophytes), which produce male gametes (sperm ...

from the lining of the hypanthium, subsequently transferring it to the next flower they visit, usually a neighbouring plant, facilitating

pollination Pollination is the transfer of pollen from an anther of a plant to the stigma (botany), stigma of a plant, later enabling fertilisation and the production of seeds. Pollinating agents can be animals such as insects, for example bees, beetles or bu ...

. The stamens borne on the hypanthium are the pollen-producing reproductive organs of the flower. The hypanthium helps in many ways with the reproduction pathways of most plants. It provides weather protection and a medium to sustain the lost pollen, increasing the probability of fertility and cross-pollination. The retained pollen can then attach to

pollinator A pollinator is an animal that moves pollen from the male anther of a flower to the female carpel, stigma of a flower. This helps to bring about fertilization of the ovules in the flower by the male gametes from the pollen grains. Insects are ...

s such as birds, bees, moths, beetles, bats, butterflies and other animals. Wind can act as an instigator for

fertilisation Fertilisation or fertilization (see spelling differences), also known as generative fertilisation, syngamy and impregnation, is the fusion of gametes to give rise to a zygote and initiate its development into a new individual organism or of ...

. The hypanthium is also an adaptive feature for structural support. It helps the

stem Stem or STEM most commonly refers to: * Plant stem, a structural axis of a vascular plant * Stem group * Science, technology, engineering, and mathematics Stem or STEM can also refer to: Language and writing * Word stem, part of a word respon ...

fuse with the flower, in turn strengthening the bond and overall stability and integrity.

References

Bibliography

Books

* * * * *

Websites

External links

* Hypanthium images o
MorphBank
a biological image database {{Botany Plant morphology