Question

The inflorescence in which-of the following plants is a dichasial cyme
A. Mustard
B. Banana
C. Coriander
D. Jasmine

Answer 1

Inflorescence is a flowering part of the plant, a cluster of flowers on a branch or a system of branches. An inflorescence is categorized based on the arrangement of flowers on the main axis (peduncle) and by the timing of its flowering (determinate and indeterminate). The inflorescence of the flower that belongs to the order Lamiales has a dichasial cyme.

Complete answer: The inflorescence of Jasmine are born with a minimum of three flowers in cymose clusters, although they may also be solitary on the ends of the branchlets. They possess a dichasial cyme, i.e. a determinate inflorescence in which growth of the central axis is terminated by a flower that opens first and each pair of branches subtending this flower then is terminated by a single flower. There are about four to nine petals for each flower, two locules, and one to four ovules. With very short filaments, they have two stamens. The bracts are ovate or linear. The calyx is bell-shaped and usually, they are very fragrant.
a) Mustard: The inflorescence, with each flower attached to a short stalk (pedicel), is called a raceme. The ovaries of older flowers enlarge into slender silica (red arrow) as the blossoms mature and the petals wither and fall down. In deciding such mustard species, the shape of the silique (flattened vs. rounded or terete) is important.
b) Banana: Banana inflorescence is a thyrse (an inflorescence in which the main axis continues to grow and the lateral branches have determinate growth). In cultured bananas, the ovary begins to develop into a seedless fruit by parthenocarpy (without being pollinated).
c) Coriander: The flowers are born in tiny umbels, asymmetrical, white or very light pink, with the petals pointing longer from the middle of the umbel than those pointing toward it. A globular, dry schizocarp 3-5 mm in diameter is the fruit. The size of the pollen is about 33 microns.
Hence, the correct answer is option D.

Note: An inflorescence is a group or cluster of flowers consisting of the main branch or a complex arrangement of branches arranged on a stem. Cyme is a flower cluster arrangement with a central stem bearing a single terminal flower that first grows and the other flowers grow as terminal buds of lateral stems in the cluster.