angiosperms Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (), commonly called angiosperms. The term "angiosperm" is derived from the Greek words ('container, vessel') and ('seed'), and refers to those plants th ...

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

stamen The stamen (plural ''stamina'' or ''stamens'') is the pollen-producing reproductive organ of a flower. Collectively the stamens form the androecium., p. 10 Morphology and terminology A stamen typically consists of a stalk called the filame ...

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

corolla tube Petals are modified leaves that surround the reproductive parts of flowers. They are often brightly colored or unusually shaped to attract pollinators. All of the petals of a flower are collectively known as the ''corolla''. Petals are usuall ...

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 The term ''sepalum'' was coine ...

. It often contains the nectaries of the

plant Plants are predominantly photosynthetic eukaryotes of the kingdom Plantae. Historically, the plant kingdom encompassed all living things that were not animals, and included algae and fungi; however, all current definitions of Plantae exclud ...

. 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. Some geometric 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 arbutifolia'' (; more commonly by Californian botanists), commonly known as toyon, is a common perennial shrub native to extreme southwest Oregon, California, and the Baja California Peninsula. It is the sole species in the genus ...

, whereas some are saucer-shaped as in '' Mitella caulescens''. Its presence is diagnostic of many

families Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Ideal ...

, including the Rosaceae,

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 various species are known as currants or gooseberries, and some are cultivated for their edible ...

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

eucalypt Eucalypt is a descriptive name for woody plants with capsule fruiting bodies belonging to seven closely related genera (of the tribe Eucalypteae) found across Australasia: ''Eucalyptus'', ''Corymbia'', ''Angophora'', '' Stockwellia'', ''Allosyn ...

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

hip In vertebrate anatomy, hip (or "coxa"Latin ''coxa'' was used by Celsus in the sense "hip", but by Pliny the Elder in the sense "hip bone" (Diab, p 77) in medical terminology) refers to either an anatomical region or a joint. The hip region is ...

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, petals and either the stamen or multiple stamen that are attached at one or two points. The flowers of the family Rosaceae, or the

rose A rose is either a woody perennial flowering plant of the genus ''Rosa'' (), in the family Rosaceae (), or the flower it bears. There are over three hundred species and tens of thousands of cultivars. They form a group of plants that can be ...

family, always have some type of hypanthium or at least a floral cup from which the sepals, petals and stamens all arise, and which is lined with nectar-producing tissue known as nectaries. The nectar is a sugary substance that attracts

bird Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweigh ...

s and bees to the flower, who then take the pollen from the lining of the hypanthium and transfer it to the next flower they visit, usually a neighbouring plant. The stamens borne on the hypanthium are the pollen-producing

reproductive organs A sex organ (or reproductive organ) is any part of an animal or plant that is involved in sexual reproduction. The reproductive organs together constitute the reproductive system. In animals, the testis in the male, and the ovary in the female, a ...

of the flower. The hypanthium helps in many ways with the reproduction and

cross pollination Pollination is the transfer of pollen from an anther of a plant to the stigma of a plant, later enabling fertilisation and the production of seeds, most often by an animal or by wind. Pollinating agents can be animals such as insects, birds, a ...

pathways of most plants. It provides

weather Weather is the state of the atmosphere, describing for example the degree to which it is hot or cold, wet or dry, calm or stormy, clear or cloudy. On Earth, most weather phenomena occur in the lowest layer of the planet's atmosphere, the ...

protection and a medium to sustain the lost pollen, increasing the probability of fertility and cross-pollination. The retained pollen can then attach to pollinators such as

s, bees,

moth Moths are a paraphyletic group of insects that includes all members of the order Lepidoptera that are not butterflies, with moths making up the vast majority of the order. There are thought to be approximately 160,000 species of moth, many of w ...

beetle Beetles are insects that form the order Coleoptera (), in the superorder Endopterygota. Their front pair of wings are hardened into wing-cases, elytra, distinguishing them from most other insects. The Coleoptera, with about 400,000 describ ...

bat Bats are mammals of the order Chiroptera.''cheir'', "hand" and πτερόν''pteron'', "wing". With their forelimbs adapted as wings, they are the only mammals capable of true and sustained flight. Bats are more agile in flight than most ...

butterflies Butterflies are insects in the macrolepidopteran clade Rhopalocera from the Order (biology), order Lepidoptera, which also includes moths. Adult butterflies have large, often brightly coloured wings, and conspicuous, fluttering flight. The ...

and other

animal Animals are multicellular, eukaryotic organisms in the Kingdom (biology), biological kingdom Animalia. With few exceptions, animals Heterotroph, consume organic material, Cellular respiration#Aerobic respiration, breathe oxygen, are Motilit ...

Wind Wind is the natural movement of air or other gases relative to a planet's surface. Winds occur on a range of scales, from thunderstorm flows lasting tens of minutes, to local breezes generated by heating of land surfaces and lasting a few ho ...

can act as an instigator for fertilisation. The hypanthium is also an adaptive feature for structural support. It helps the stem fuse with the flower, in turn strengthening the bond and overall stability and integrity.

References

Bibliography

Books

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Websites

External links

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