Inflorescence varies in different plants, it is the way the flowers are arranged on the floral axis of plants. Inflorescence are of three types, mainly:
- Racemose – indeterminate or indefinite
- Cymose – determinate or definite
- Mixed
Cyathium is a special type of cymose inflorescence.
Cyathium Inflorescence Definition
Cyathium is one of the specialised pseudanthium or false flowers which forms the inflorescence of plants. It can be seen in the genus of the Euphorbia. Here, the brackets fuse to form a cup-shaped structure. Some secretory glands can be seen on the margin or the periphery of the cup. Here, in this cup, the female flowers are engirdled by great numbers of male flowers, appearing as a single flower.
The axis in this type of inflorescence gets suppressed, which forms a convex receptacle. The receptacle’s centre shows a long-stalked and naked female flower which has a tricarpellary gynoecium, wrapped by huge numbers of male flowers arranged in a scorpioid cyme.
The cyathium comprises:
- Five bracteoles (four rarely)
They are united and small bracts forming a cup-like involucre. The upper tips are free and at the state cover the opening of the involucre. It alternates with –
- Five nectary glands (one to ten)
At times these are fused.
- One female flower
It is extremely reduced and positioned in the centre, at the base of the involucre. It comprises an ovary on a short stem having pistil. It is surrounded by –
- Five groups of male flowers
These are extremely reduced (one group is at the base of each of the bracteole). Each of these reduced male flowers has a single anther on the stem.
The flower-like features of Cyathia are marked by vibrant coloured nectar glands and usually by petal-like appendages to the nectar glands or the brightly coloured petal-like bracts found under the cyathia. Sometimes, the cyathia are solitary, in cymes usually, wherein the inflorescences are of the second order in the pseudumbels on the dichotomously branched stalks or in the simple cymes comprising one cyathium at the centre and two lateral.
Cyathium Inflorescence Example
Cyathium inflorescence can be seen in the Euphorbia species and Poinsettia.
Where can Cyathium Inflorescence be seen?
Cyathium: Inflorescence of the Euphorbia Family
Euphorbia is one of the largest genera of flowering plants, with close to 2000 species. This huge genus is part of the extremely diverse Euphorbia family (Euphorbiaceae), having close to 75 species. This genus shows an incredible diversity. The red, showy modified leaves of the poinsettia are mistaken for petals while they are not even part of true flowers.
It surrounds clusters of greenish, small and cup-shaped structures referred to as cyathia. Each of the cyathia is an inflorescence or flower cluster actually, which contains apetalous, unisexual female and male flowers. The inconspicuous male flowers are seen in clusters and reduced to a single red stamen. The female flowers, on the other hand, comprise a single ovary on the stalk. The ovary in poinsettia is concealed inside the cyathium. However, in other species, the ovary projects out of the cyathium at the time of maturity.
The cyathium’s rim has numerous greenish nectar glands which appear attractive to the insect pollinators. The glands in some species are subtended by the petaloid appendages (petal-like bracts). Usually, the Poinsettias show only one greenish gland for each cyathium with the absence of petaloid appendages.
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Frequently Asked Questions on Cyathium Inflorescence
What is cyathium inflorescence?
Cyathium inflorescence is a special type of cymose inflorescence; wherein there is a cup-like cluster of altered leaves that surrounds a female flower and many male flowers. It appears as a single flower.
Where can cyathium inflorescence be seen?
Cyathium inflorescence can be seen in Poinsettia.
Give an example of cyathium inflorescence.
The Euphorbia species shows cyathium inflorescence.
Which family has cyathium inflorescence?
The Euphorbia family (Euphorbiaceae) shows cyathium inflorescence.
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