Question

Which of the following is true' Which of the following is true?
A. Umbel is a racemose inflorescence where all stalked flowers aggregate on the flat receptacle.
B. Raceme is a racemose inflorescence having main axis shortened & flower born acropetally.
C. Spadix is a racemose inflorescence having a pendulous spike with the main axis much flattened.
D. Spike is a racemose inflorescence having sessile flowers.

Answer 1

Hint: Racemose is a form of inflorescence in which the main axis keeps growing indefinitely and does not end in flower. That's why it is also known as an indefinite or indefinite inflorescence.

Complete step by step answer: Spike is a racemose inflorescence which grows sessile flowers in the acropetal fashion, e.g., chiffon flower also called as Achyranthes, bottle brush also called as Callisteinon, Adhatoda vasica, Amaranthus. The compound spike is known as the spike spike. Sessile flowers (spikelets) are present on the branched main axis. Examples are: wheat , barley, sorghum, oats, etc.
Hence, with this we can conclude that option D is the correct answer.

Additional Information: Racemose inflorescence main features:
-The development of the main axis (peduncle) is indefinite and tends to produce a bud of flowers.
-The peduncle seldom ends up in a flower.
-Peduncle is a monopodal
-The first flowers produced are produced at the base of the peduncle.
-The flowers are borne laterally in acropetal succession, i.e. the older flowers are at the base and the younger flowers at the top.
-The flower group is arranged centripetal, i.e. the younger flowers in the centre and the older flowers in the periphery.
-The newly shaped fruit is not covered by flowers.
-Flower grouping is less common

Note: If the axis is short or stunted, the flowers come from a common point and tend to be at about the same height. This pattern, labeled umbel (see photo), is actually a flattened raceme, since the inner circles of the axis, or peduncle (the origin of the leaves and flower axes), are reduced so that the pedicels are of the same length ( e.g. the carrot family). The head is a raceme in which the peduncle is flattened and the flowers are directly attached to it. This results in smaller flower grouping in such a way that it appears as a single flower. In several members of the Asteraceae, for example, the outer (or ray) flowers have a well-developed zygomorphic corolla, and the inner (disc) flowers have a small actinomorphic corolla. The inner disc flowers are usually full flowers, and the ray flowers are usually sterile.