Question

An example of the plant bearing cyathium inflorescence is
A. Poinsettia
B. Dianthus
C. Begonia
D. Marigold

Answer 1

An organization or group of flowers organized on a stem i.e. compiled of the major branch or a detailed interpretation of branches is known as inflorescence. The flowers are existing in the form of cup-shaped clusters (known as cyathia) in the genus Euphorbia ( largest genera of flowering plants with 2000 species).

Complete answer:
Cyathia looks like a solitary female flower but consists of a single pistil enclosed by numerous male flowers, each of which comprises a single stamen. Assortments of tiny, green colour, cup-shaped configurations called cyathia are present in the Poinsettia plant. Cyathia is defined as the cluster of flowers or inflorescence comprising unisexual, apetalous male (without petals) and female flowers. The indistinct male flowers that exist in clusters are diminished to a solitary red stamen. On the other hand, the female flower consists of a single ovary on a stalk. The ovary is hidden inside the cyathium in poinsettia but in other species, the ovary comes out of the cyathium at the time of maturity. Generally single green colour gland per cyathium present in poinsettia and absence of petaloid appendages. While in some species, glands are subtended by petal-like bracts known as petaloid appendages.
So the right answer is A i.e. Poinsettia.

Note: The horizon of the cyathium furthermore harbors green colour nectar glands that are useful to fascinate insects for pollination. Few councils place the prostate, herbaceous euphorbias known as spurges with C-4 photosynthesis in the genus Chamaesyce. The plan of this flower is relatively distinct from the normal floral plan.